Commit Graph

13311 Commits

Author SHA1 Message Date
Linus Torvalds
0923fd0419 Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "Lock debugging:

   - Implement compiler-driven static analysis locking context checking,
     using the upcoming Clang 22 compiler's context analysis features
     (Marco Elver)

     We removed Sparse context analysis support, because prior to
     removal even a defconfig kernel produced 1,700+ context tracking
     Sparse warnings, the overwhelming majority of which are false
     positives. On an allmodconfig kernel the number of false positive
     context tracking Sparse warnings grows to over 5,200... On the plus
     side of the balance actual locking bugs found by Sparse context
     analysis is also rather ... sparse: I found only 3 such commits in
     the last 3 years. So the rate of false positives and the
     maintenance overhead is rather high and there appears to be no
     active policy in place to achieve a zero-warnings baseline to move
     the annotations & fixers to developers who introduce new code.

     Clang context analysis is more complete and more aggressive in
     trying to find bugs, at least in principle. Plus it has a different
     model to enabling it: it's enabled subsystem by subsystem, which
     results in zero warnings on all relevant kernel builds (as far as
     our testing managed to cover it). Which allowed us to enable it by
     default, similar to other compiler warnings, with the expectation
     that there are no warnings going forward. This enforces a
     zero-warnings baseline on clang-22+ builds (Which are still limited
     in distribution, admittedly)

     Hopefully the Clang approach can lead to a more maintainable
     zero-warnings status quo and policy, with more and more subsystems
     and drivers enabling the feature. Context tracking can be enabled
     for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
     disabled), but this will generate a lot of false positives.

     ( Having said that, Sparse support could still be added back,
       if anyone is interested - the removal patch is still
       relatively straightforward to revert at this stage. )

  Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)

    - Add support for Atomic<i8/i16/bool> and replace most Rust native
      AtomicBool usages with Atomic<bool>

    - Clean up LockClassKey and improve its documentation

    - Add missing Send and Sync trait implementation for SetOnce

    - Make ARef Unpin as it is supposed to be

    - Add __rust_helper to a few Rust helpers as a preparation for
      helper LTO

    - Inline various lock related functions to avoid additional function
      calls

  WW mutexes:

    - Extend ww_mutex tests and other test-ww_mutex updates (John
      Stultz)

  Misc fixes and cleanups:

    - rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
      Bergmann)

    - locking/local_lock: Include more missing headers (Peter Zijlstra)

    - seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)

    - rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
      Duberstein)"

* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
  locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
  rcu: Mark lockdep_assert_rcu_helper() __always_inline
  compiler-context-analysis: Remove __assume_ctx_lock from initializers
  tomoyo: Use scoped init guard
  crypto: Use scoped init guard
  kcov: Use scoped init guard
  compiler-context-analysis: Introduce scoped init guards
  cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
  seqlock: fix scoped_seqlock_read kernel-doc
  tools: Update context analysis macros in compiler_types.h
  rust: sync: Replace `kernel::c_str!` with C-Strings
  rust: sync: Inline various lock related methods
  rust: helpers: Move #define __rust_helper out of atomic.c
  rust: wait: Add __rust_helper to helpers
  rust: time: Add __rust_helper to helpers
  rust: task: Add __rust_helper to helpers
  rust: sync: Add __rust_helper to helpers
  rust: refcount: Add __rust_helper to helpers
  rust: rcu: Add __rust_helper to helpers
  rust: processor: Add __rust_helper to helpers
  ...
2026-02-10 12:28:44 -08:00
Linus Torvalds
f17b474e36 Merge tag 'bpf-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:

 - Support associating BPF program with struct_ops (Amery Hung)

 - Switch BPF local storage to rqspinlock and remove recursion detection
   counters which were causing false positives (Amery Hung)

 - Fix live registers marking for indirect jumps (Anton Protopopov)

 - Introduce execution context detection BPF helpers (Changwoo Min)

 - Improve verifier precision for 32bit sign extension pattern
   (Cupertino Miranda)

 - Optimize BTF type lookup by sorting vmlinux BTF and doing binary
   search (Donglin Peng)

 - Allow states pruning for misc/invalid slots in iterator loops (Eduard
   Zingerman)

 - In preparation for ASAN support in BPF arenas teach libbpf to move
   global BPF variables to the end of the region and enable arena kfuncs
   while holding locks (Emil Tsalapatis)

 - Introduce support for implicit arguments in kfuncs and migrate a
   number of them to new API. This is a prerequisite for cgroup
   sub-schedulers in sched-ext (Ihor Solodrai)

 - Fix incorrect copied_seq calculation in sockmap (Jiayuan Chen)

 - Fix ORC stack unwind from kprobe_multi (Jiri Olsa)

 - Speed up fentry attach by using single ftrace direct ops in BPF
   trampolines (Jiri Olsa)

 - Require frozen map for calculating map hash (KP Singh)

 - Fix lock entry creation in TAS fallback in rqspinlock (Kumar
   Kartikeya Dwivedi)

 - Allow user space to select cpu in lookup/update operations on per-cpu
   array and hash maps (Leon Hwang)

 - Make kfuncs return trusted pointers by default (Matt Bobrowski)

 - Introduce "fsession" support where single BPF program is executed
   upon entry and exit from traced kernel function (Menglong Dong)

 - Allow bpf_timer and bpf_wq use in all programs types (Mykyta
   Yatsenko, Andrii Nakryiko, Kumar Kartikeya Dwivedi, Alexei
   Starovoitov)

 - Make KF_TRUSTED_ARGS the default for all kfuncs and clean up their
   definition across the tree (Puranjay Mohan)

 - Allow BPF arena calls from non-sleepable context (Puranjay Mohan)

 - Improve register id comparison logic in the verifier and extend
   linked registers with negative offsets (Puranjay Mohan)

 - In preparation for BPF-OOM introduce kfuncs to access memcg events
   (Roman Gushchin)

 - Use CFI compatible destructor kfunc type (Sami Tolvanen)

 - Add bitwise tracking for BPF_END in the verifier (Tianci Cao)

 - Add range tracking for BPF_DIV and BPF_MOD in the verifier (Yazhou
   Tang)

 - Make BPF selftests work with 64k page size (Yonghong Song)

* tag 'bpf-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (268 commits)
  selftests/bpf: Fix outdated test on storage->smap
  selftests/bpf: Choose another percpu variable in bpf for btf_dump test
  selftests/bpf: Remove test_task_storage_map_stress_lookup
  selftests/bpf: Update task_local_storage/task_storage_nodeadlock test
  selftests/bpf: Update task_local_storage/recursion test
  selftests/bpf: Update sk_storage_omem_uncharge test
  bpf: Switch to bpf_selem_unlink_nofail in bpf_local_storage_{map_free, destroy}
  bpf: Support lockless unlink when freeing map or local storage
  bpf: Prepare for bpf_selem_unlink_nofail()
  bpf: Remove unused percpu counter from bpf_local_storage_map_free
  bpf: Remove cgroup local storage percpu counter
  bpf: Remove task local storage percpu counter
  bpf: Change local_storage->lock and b->lock to rqspinlock
  bpf: Convert bpf_selem_unlink to failable
  bpf: Convert bpf_selem_link_map to failable
  bpf: Convert bpf_selem_unlink_map to failable
  bpf: Select bpf_local_storage_map_bucket based on bpf_local_storage
  selftests/xsk: fix number of Tx frags in invalid packet
  selftests/xsk: properly handle batch ending in the middle of a packet
  bpf: Prevent reentrance into call_rcu_tasks_trace()
  ...
2026-02-10 11:26:21 -08:00
Jibin Zhang
426ca15c7f net: fix segmentation of forwarding fraglist GRO
This patch enhances GSO segment handling by properly checking
the SKB_GSO_DODGY flag for frag_list GSO packets, addressing
low throughput issues observed when a station accesses IPv4
servers via hotspots with an IPv6-only upstream interface.

Specifically, it fixes a bug in GSO segmentation when forwarding
GRO packets containing a frag_list. The function skb_segment_list
cannot correctly process GRO skbs that have been converted by XLAT,
since XLAT only translates the header of the head skb. Consequently,
skbs in the frag_list may remain untranslated, resulting in protocol
inconsistencies and reduced throughput.

To address this, the patch explicitly sets the SKB_GSO_DODGY flag
for GSO packets in XLAT's IPv4/IPv6 protocol translation helpers
(bpf_skb_proto_4_to_6 and bpf_skb_proto_6_to_4). This marks GSO
packets as potentially modified after protocol translation. As a
result, GSO segmentation will avoid using skb_segment_list and
instead falls back to skb_segment for packets with the SKB_GSO_DODGY
flag. This ensures that only safe and fully translated frag_list
packets are processed by skb_segment_list, resolving protocol
inconsistencies and improving throughput when forwarding GRO packets
converted by XLAT.

Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com>
Fixes: 9fd1ff5d2a ("udp: Support UDP fraglist GRO/GSO.")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260126152114.1211-1-jibin.zhang@mediatek.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-01-29 14:40:12 +01:00
Jiayuan Chen
929e30f931 bpf, sockmap: Fix FIONREAD for sockmap
A socket using sockmap has its own independent receive queue: ingress_msg.
This queue may contain data from its own protocol stack or from other
sockets.

Therefore, for sockmap, relying solely on copied_seq and rcv_nxt to
calculate FIONREAD is not enough.

This patch adds a new msg_tot_len field in the psock structure to record
the data length in ingress_msg. Additionally, we implement new ioctl
interfaces for TCP and UDP to intercept FIONREAD operations.

Note that we intentionally do not include sk_receive_queue data in the
FIONREAD result. Data in sk_receive_queue has not yet been processed by
the BPF verdict program, and may be redirected to other sockets or
dropped. Including it would create semantic ambiguity since this data
may never be readable by the user.

Unix and VSOCK sockets have similar issues, but fixing them is outside
the scope of this patch as it would require more intrusive changes.

Previous work by John Fastabend made some efforts towards FIONREAD support:
commit e5c6de5fa0 ("bpf, sockmap: Incorrectly handling copied_seq")
Although the current patch is based on the previous work by John Fastabend,
it is acceptable for our Fixes tag to point to the same commit.

                                                      FD1:read()
                                                      --  FD1->copied_seq++
                                                          |  [read data]
                                                          |
                                   [enqueue data]         v
                  [sockmap]     -> ingress to self ->  ingress_msg queue
FD1 native stack  ------>                                 ^
-- FD1->rcv_nxt++               -> redirect to other      | [enqueue data]
                                       |                  |
                                       |             ingress to FD1
                                       v                  ^
                                      ...                 |  [sockmap]
                                                     FD2 native stack

Fixes: 04919bed94 ("tcp: Introduce tcp_read_skb()")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20260124113314.113584-3-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-27 09:11:30 -08:00
Jiayuan Chen
b40cc5adaa bpf, sockmap: Fix incorrect copied_seq calculation
A socket using sockmap has its own independent receive queue: ingress_msg.
This queue may contain data from its own protocol stack or from other
sockets.

The issue is that when reading from ingress_msg, we update tp->copied_seq
by default. However, if the data is not from its own protocol stack,
tcp->rcv_nxt is not increased. Later, if we convert this socket to a
native socket, reading from this socket may fail because copied_seq might
be significantly larger than rcv_nxt.

This fix also addresses the syzkaller-reported bug referenced in the
Closes tag.

This patch marks the skmsg objects in ingress_msg. When reading, we update
copied_seq only if the data is from its own protocol stack.

                                                     FD1:read()
                                                     --  FD1->copied_seq++
                                                         |  [read data]
                                                         |
                                [enqueue data]           v
                  [sockmap]     -> ingress to self ->  ingress_msg queue
FD1 native stack  ------>                                 ^
-- FD1->rcv_nxt++               -> redirect to other      | [enqueue data]
                                       |                  |
                                       |             ingress to FD1
                                       v                  ^
                                      ...                 |  [sockmap]
                                                     FD2 native stack

Closes: https://syzkaller.appspot.com/bug?extid=06dbd397158ec0ea4983
Fixes: 04919bed94 ("tcp: Introduce tcp_read_skb()")
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20260124113314.113584-2-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-27 09:11:30 -08:00
Kuniyuki Iwashima
7a9bc9e3f4 fou: Don't allow 0 for FOU_ATTR_IPPROTO.
fou_udp_recv() has the same problem mentioned in the previous
patch.

If FOU_ATTR_IPPROTO is set to 0, skb is not freed by
fou_udp_recv() nor "resubmit"-ted in ip_protocol_deliver_rcu().

Let's forbid 0 for FOU_ATTR_IPPROTO.

Fixes: 23461551c0 ("fou: Support for foo-over-udp RX path")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260115172533.693652-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-17 16:00:24 -08:00
Kuniyuki Iwashima
9a56796ad2 gue: Fix skb memleak with inner IP protocol 0.
syzbot reported skb memleak below. [0]

The repro generated a GUE packet with its inner protocol 0.

gue_udp_recv() returns -guehdr->proto_ctype for "resubmit"
in ip_protocol_deliver_rcu(), but this only works with
non-zero protocol number.

Let's drop such packets.

Note that 0 is a valid number (IPv6 Hop-by-Hop Option).

I think it is not practical to encap HOPOPT in GUE, so once
someone starts to complain, we could pass down a resubmit
flag pointer to distinguish two zeros from the upper layer:

  * no error
  * resubmit HOPOPT

[0]
BUG: memory leak
unreferenced object 0xffff888109695a00 (size 240):
  comm "syz.0.17", pid 6088, jiffies 4294943096
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00  .@..............
  backtrace (crc a84b336f):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4958 [inline]
    slab_alloc_node mm/slub.c:5263 [inline]
    kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270
    __build_skb+0x23/0x60 net/core/skbuff.c:474
    build_skb+0x20/0x190 net/core/skbuff.c:490
    __tun_build_skb drivers/net/tun.c:1541 [inline]
    tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636
    tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770
    tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999
    new_sync_write fs/read_write.c:593 [inline]
    vfs_write+0x45d/0x710 fs/read_write.c:686
    ksys_write+0xa7/0x170 fs/read_write.c:738
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: 37dd024779 ("gue: Receive side for Generic UDP Encapsulation")
Reported-by: syzbot+4d8c7d16b0e95c0d0f0d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6965534b.050a0220.38aacd.0001.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260115172533.693652-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-17 16:00:23 -08:00
Paolo Abeni
5ce234a8fe Merge tag 'ipsec-2026-01-14' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec
Steffen Klassert says:

====================
pull request (net): ipsec 2026-01-14

1) Fix inner mode lookup in tunnel mode GSO segmentation.
   The protocol was taken from the wrong field.

2) Set ipv4 no_pmtu_disc flag only on output SAs. The
   insertation of input SAs can fail if no_pmtu_disc
   is set.

Please pull or let me know if there are problems.

ipsec-2026-01-14

* tag 'ipsec-2026-01-14' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
  xfrm: set ipv4 no_pmtu_disc flag only on output sa when direction is set
  xfrm: Fix inner mode lookup in tunnel mode GSO segmentation
====================

Link: https://patch.msgid.link/20260114121817.1106134-1-steffen.klassert@secunet.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-01-15 12:46:12 +01:00
Eric Dumazet
9a6f0c4d57 dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()
syzbot was able to crash the kernel in rt6_uncached_list_flush_dev()
in an interesting way [1]

Crash happens in list_del_init()/INIT_LIST_HEAD() while writing
list->prev, while the prior write on list->next went well.

static inline void INIT_LIST_HEAD(struct list_head *list)
{
	WRITE_ONCE(list->next, list); // This went well
	WRITE_ONCE(list->prev, list); // Crash, @list has been freed.
}

Issue here is that rt6_uncached_list_del() did not attempt to lock
ul->lock, as list_empty(&rt->dst.rt_uncached) returned
true because the WRITE_ONCE(list->next, list) happened on the other CPU.

We might use list_del_init_careful() and list_empty_careful(),
or make sure rt6_uncached_list_del() always grabs the spinlock
whenever rt->dst.rt_uncached_list has been set.

A similar fix is neeed for IPv4.

[1]

 BUG: KASAN: slab-use-after-free in INIT_LIST_HEAD include/linux/list.h:46 [inline]
 BUG: KASAN: slab-use-after-free in list_del_init include/linux/list.h:296 [inline]
 BUG: KASAN: slab-use-after-free in rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]
 BUG: KASAN: slab-use-after-free in rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020
Write of size 8 at addr ffff8880294cfa78 by task kworker/u8:14/3450

CPU: 0 UID: 0 PID: 3450 Comm: kworker/u8:14 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
  dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
  print_address_description mm/kasan/report.c:378 [inline]
  print_report+0xca/0x240 mm/kasan/report.c:482
  kasan_report+0x118/0x150 mm/kasan/report.c:595
  INIT_LIST_HEAD include/linux/list.h:46 [inline]
  list_del_init include/linux/list.h:296 [inline]
  rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]
  rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020
  addrconf_ifdown+0x143/0x18a0 net/ipv6/addrconf.c:3853
 addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1
  notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
  call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
  call_netdevice_notifiers net/core/dev.c:2282 [inline]
  netif_close_many+0x29c/0x410 net/core/dev.c:1785
  unregister_netdevice_many_notify+0xb50/0x2330 net/core/dev.c:12353
  ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
  ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248
  cleanup_net+0x4de/0x7b0 net/core/net_namespace.c:696
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 803:
  kasan_save_stack mm/kasan/common.c:57 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
  unpoison_slab_object mm/kasan/common.c:340 [inline]
  __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
  kasan_slab_alloc include/linux/kasan.h:253 [inline]
  slab_post_alloc_hook mm/slub.c:4953 [inline]
  slab_alloc_node mm/slub.c:5263 [inline]
  kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
  dst_alloc+0x105/0x170 net/core/dst.c:89
  ip6_dst_alloc net/ipv6/route.c:342 [inline]
  icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333
  mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844
  mld_send_cr net/ipv6/mcast.c:2154 [inline]
  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Freed by task 20:
  kasan_save_stack mm/kasan/common.c:57 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
  kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
  poison_slab_object mm/kasan/common.c:253 [inline]
  __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
  kasan_slab_free include/linux/kasan.h:235 [inline]
  slab_free_hook mm/slub.c:2540 [inline]
  slab_free mm/slub.c:6670 [inline]
  kmem_cache_free+0x18f/0x8d0 mm/slub.c:6781
  dst_destroy+0x235/0x350 net/core/dst.c:121
  rcu_do_batch kernel/rcu/tree.c:2605 [inline]
  rcu_core kernel/rcu/tree.c:2857 [inline]
  rcu_cpu_kthread+0xba5/0x1af0 kernel/rcu/tree.c:2945
  smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Last potentially related work creation:
  kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
  kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
  __call_rcu_common kernel/rcu/tree.c:3119 [inline]
  call_rcu+0xee/0x890 kernel/rcu/tree.c:3239
  refdst_drop include/net/dst.h:266 [inline]
  skb_dst_drop include/net/dst.h:278 [inline]
  skb_release_head_state+0x71/0x360 net/core/skbuff.c:1156
  skb_release_all net/core/skbuff.c:1180 [inline]
  __kfree_skb net/core/skbuff.c:1196 [inline]
  sk_skb_reason_drop+0xe9/0x170 net/core/skbuff.c:1234
  kfree_skb_reason include/linux/skbuff.h:1322 [inline]
  tcf_kfree_skb_list include/net/sch_generic.h:1127 [inline]
  __dev_xmit_skb net/core/dev.c:4260 [inline]
  __dev_queue_xmit+0x26aa/0x3210 net/core/dev.c:4785
  NF_HOOK_COND include/linux/netfilter.h:307 [inline]
  ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
  NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
  mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
  mld_send_cr net/ipv6/mcast.c:2154 [inline]
  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

The buggy address belongs to the object at ffff8880294cfa00
 which belongs to the cache ip6_dst_cache of size 232
The buggy address is located 120 bytes inside of
 freed 232-byte region [ffff8880294cfa00, ffff8880294cfae8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x294cf
memcg:ffff88803536b781
flags: 0x80000000000000(node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000000 ffff88802ff1c8c0 ffffea0000bf2bc0 dead000000000006
raw: 0000000000000000 00000000800c000c 00000000f5000000 ffff88803536b781
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 9, tgid 9 (kworker/0:0), ts 91119585830, free_ts 91088628818
  set_page_owner include/linux/page_owner.h:32 [inline]
  post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857
  prep_new_page mm/page_alloc.c:1865 [inline]
  get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915
  __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
  alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
  alloc_slab_page mm/slub.c:3075 [inline]
  allocate_slab+0x86/0x3b0 mm/slub.c:3248
  new_slab mm/slub.c:3302 [inline]
  ___slab_alloc+0xb10/0x13e0 mm/slub.c:4656
  __slab_alloc+0xc6/0x1f0 mm/slub.c:4779
  __slab_alloc_node mm/slub.c:4855 [inline]
  slab_alloc_node mm/slub.c:5251 [inline]
  kmem_cache_alloc_noprof+0x101/0x6c0 mm/slub.c:5270
  dst_alloc+0x105/0x170 net/core/dst.c:89
  ip6_dst_alloc net/ipv6/route.c:342 [inline]
  icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333
  mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844
  mld_send_cr net/ipv6/mcast.c:2154 [inline]
  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
page last free pid 5859 tgid 5859 stack trace:
  reset_page_owner include/linux/page_owner.h:25 [inline]
  free_pages_prepare mm/page_alloc.c:1406 [inline]
  __free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2943
  discard_slab mm/slub.c:3346 [inline]
  __put_partials+0x149/0x170 mm/slub.c:3886
  __slab_free+0x2af/0x330 mm/slub.c:5952
  qlink_free mm/kasan/quarantine.c:163 [inline]
  qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
  kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
  __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
  kasan_slab_alloc include/linux/kasan.h:253 [inline]
  slab_post_alloc_hook mm/slub.c:4953 [inline]
  slab_alloc_node mm/slub.c:5263 [inline]
  kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
  getname_flags+0xb8/0x540 fs/namei.c:146
  getname include/linux/fs.h:2498 [inline]
  do_sys_openat2+0xbc/0x200 fs/open.c:1426
  do_sys_open fs/open.c:1436 [inline]
  __do_sys_openat fs/open.c:1452 [inline]
  __se_sys_openat fs/open.c:1447 [inline]
  __x64_sys_openat+0x138/0x170 fs/open.c:1447
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94

Fixes: 8d0b94afdc ("ipv6: Keep track of DST_NOCACHE routes in case of iface down/unregister")
Fixes: 78df76a065 ("ipv4: take rt_uncached_lock only if needed")
Reported-by: syzbot+179fc225724092b8b2b2@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6964cdf2.050a0220.eaf7.009d.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260112103825.3810713-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-13 19:08:18 -08:00
Eric Dumazet
e67c577d89 ipv4: ip_gre: make ipgre_header() robust
Analog to commit db5b4e39c4 ("ip6_gre: make ip6gre_header() robust")

Over the years, syzbot found many ways to crash the kernel
in ipgre_header() [1].

This involves team or bonding drivers ability to dynamically
change their dev->needed_headroom and/or dev->hard_header_len

In this particular crash mld_newpack() allocated an skb
with a too small reserve/headroom, and by the time mld_sendpack()
was called, syzbot managed to attach an ipgre device.

[1]
skbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000 data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0
 kernel BUG at net/core/skbuff.c:213 !
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: mld mld_ifc_work
 RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213
Call Trace:
 <TASK>
  skb_under_panic net/core/skbuff.c:223 [inline]
  skb_push+0xc3/0xe0 net/core/skbuff.c:2641
  ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897
  dev_hard_header include/linux/netdevice.h:3436 [inline]
  neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
  NF_HOOK_COND include/linux/netfilter.h:307 [inline]
  ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
  NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
  mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
  mld_send_cr net/ipv6/mcast.c:2154 [inline]
  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Fixes: c544193214 ("GRE: Refactor GRE tunneling code.")
Reported-by: syzbot+7c134e1c3aa3283790b9@syzkaller.appspotmail.com
Closes: https://www.spinics.net/lists/netdev/msg1147302.html
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260108190214.1667040-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-10 12:06:22 -08:00
Eric Dumazet
872ac785e7 ipv4: ip_tunnel: spread netdev_lockdep_set_classes()
Inspired by yet another syzbot report.

IPv6 tunnels call netdev_lockdep_set_classes() for each tunnel type,
while IPv4 currently centralizes netdev_lockdep_set_classes() call from
ip_tunnel_init().

Make ip_tunnel_init() a macro, so that we have different lockdep
classes per tunnel type.

Fixes: 0bef512012 ("net: add netdev_lockdep_set_classes() to virtual drivers")
Reported-by: syzbot+1240b33467289f5ab50b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/695d439f.050a0220.1c677c.0347.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260106172426.1760721-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-08 18:02:35 -08:00
Eric Dumazet
c92510f5e3 arp: do not assume dev_hard_header() does not change skb->head
arp_create() is the only dev_hard_header() caller
making assumption about skb->head being unchanged.

A recent commit broke this assumption.

Initialize @arp pointer after dev_hard_header() call.

Fixes: db5b4e39c4 ("ip6_gre: make ip6gre_header() robust")
Reported-by: syzbot+58b44a770a1585795351@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260107212250.384552-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-08 09:04:24 -08:00
Willem de Bruijn
7d11e047ed net: do not write to msg_get_inq in callee
NULL pointer dereference fix.

msg_get_inq is an input field from caller to callee. Don't set it in
the callee, as the caller may not clear it on struct reuse.

This is a kernel-internal variant of msghdr only, and the only user
does reinitialize the field. So this is not critical for that reason.
But it is more robust to avoid the write, and slightly simpler code.
And it fixes a bug, see below.

Callers set msg_get_inq to request the input queue length to be
returned in msg_inq. This is equivalent to but independent from the
SO_INQ request to return that same info as a cmsg (tp->recvmsg_inq).
To reduce branching in the hot path the second also sets the msg_inq.
That is WAI.

This is a fix to commit 4d1442979e ("af_unix: don't post cmsg for
SO_INQ unless explicitly asked for"), which fixed the inverse.

Also avoid NULL pointer dereference in unix_stream_read_generic if
state->msg is NULL and msg->msg_get_inq is written. A NULL state->msg
can happen when splicing as of commit 2b514574f7 ("net: af_unix:
implement splice for stream af_unix sockets").

Also collapse two branches using a bitwise or.

Cc: stable@vger.kernel.org
Fixes: 4d1442979e ("af_unix: don't post cmsg for SO_INQ unless explicitly asked for")
Link: https://lore.kernel.org/netdev/willemdebruijn.kernel.24d8030f7a3de@gmail.com/
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260106150626.3944363-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-08 08:45:13 -08:00
Eric Dumazet
e5c8eda39a udp: call skb_orphan() before skb_attempt_defer_free()
Standard UDP receive path does not use skb->destructor.

But skmsg layer does use it, since it calls skb_set_owner_sk_safe()
from udp_read_skb().

This then triggers this warning in skb_attempt_defer_free():

    DEBUG_NET_WARN_ON_ONCE(skb->destructor);

We must call skb_orphan() to fix this issue.

Fixes: 6471658dc6 ("udp: use skb_attempt_defer_free()")
Reported-by: syzbot+3e68572cf2286ce5ebe9@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/695b83bd.050a0220.1c9965.002b.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260105093630.1976085-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-06 17:05:17 -08:00
Marco Elver
38f1311a22 compiler-context-analysis: Change __cond_acquires to take return value
While Sparse is oblivious to the return value of conditional acquire
functions, Clang's context analysis needs to know the return value
which indicates successful acquisition.

Add the additional argument, and convert existing uses.

Notably, Clang's interpretation of the value merely relates to the use
in a later conditional branch, i.e. 1 ==> context lock acquired in
branch taken if condition non-zero, and 0 ==> context lock acquired in
branch taken if condition is zero. Given the precise value does not
matter, introduce symbolic variants to use instead of either 0 or 1,
which should be more intuitive.

No functional change intended.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-10-elver@google.com
2026-01-05 16:43:29 +01:00
Florian Westphal
2ef02ac38d inet: frags: drop fraglist conntrack references
Jakub added a warning in nf_conntrack_cleanup_net_list() to make debugging
leaked skbs/conntrack references more obvious.

syzbot reports this as triggering, and I can also reproduce this via
ip_defrag.sh selftest:

 conntrack cleanup blocked for 60s
 WARNING: net/netfilter/nf_conntrack_core.c:2512
 [..]

conntrack clenups gets stuck because there are skbs with still hold nf_conn
references via their frag_list.

   net.core.skb_defer_max=0 makes the hang disappear.

Eric Dumazet points out that skb_release_head_state() doesn't follow the
fraglist.

ip_defrag.sh can only reproduce this problem since
commit 6471658dc6 ("udp: use skb_attempt_defer_free()"), but AFAICS this
problem could happen with TCP as well if pmtu discovery is off.

The relevant problem path for udp is:
1. netns emits fragmented packets
2. nf_defrag_v6_hook reassembles them (in output hook)
3. reassembled skb is tracked (skb owns nf_conn reference)
4. ip6_output refragments
5. refragmented packets also own nf_conn reference (ip6_fragment
   calls ip6_copy_metadata())
6. on input path, nf_defrag_v6_hook skips defragmentation: the
   fragments already have skb->nf_conn attached
7. skbs are reassembled via ipv6_frag_rcv()
8. skb_consume_udp -> skb_attempt_defer_free() -> skb ends up
   in pcpu freelist, but still has nf_conn reference.

Possible solutions:
 1 let defrag engine drop nf_conn entry, OR
 2 export kick_defer_list_purge() and call it from the conntrack
   netns exit callback, OR
 3 add skb_has_frag_list() check to skb_attempt_defer_free()

2 & 3 also solve ip_defrag.sh hang but share same drawback:

Such reassembled skbs, queued to socket, can prevent conntrack module
removal until userspace has consumed the packet. While both tcp and udp
stack do call nf_reset_ct() before placing skb on socket queue, that
function doesn't iterate frag_list skbs.

Therefore drop nf_conn entries when they are placed in defrag queue.
Keep the nf_conn entry of the first (offset 0) skb so that reassembled
skb retains nf_conn entry for sake of TX path.

Note that fixes tag is incorrect; it points to the commit introducing the
'ip_defrag.sh reproducible problem': no need to backport this patch to
every stable kernel.

Reported-by: syzbot+4393c47753b7808dac7d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/693b0fa7.050a0220.4004e.040d.GAE@google.com/
Fixes: 6471658dc6 ("udp: use skb_attempt_defer_free()")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260102140030.32367-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-04 10:58:04 -08:00
yuan.gao
4c0856c225 inet: ping: Fix icmp out counting
When the ping program uses an IPPROTO_ICMP socket to send ICMP_ECHO
messages, ICMP_MIB_OUTMSGS is counted twice.

    ping_v4_sendmsg
      ping_v4_push_pending_frames
        ip_push_pending_frames
          ip_finish_skb
            __ip_make_skb
              icmp_out_count(net, icmp_type); // first count
      icmp_out_count(sock_net(sk), user_icmph.type); // second count

However, when the ping program uses an IPPROTO_RAW socket,
ICMP_MIB_OUTMSGS is counted correctly only once.

Therefore, the first count should be removed.

Fixes: c319b4d76b ("net: ipv4: add IPPROTO_ICMP socket kind")
Signed-off-by: yuan.gao <yuan.gao@ucloud.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20251224063145.3615282-1-yuan.gao@ucloud.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-04 09:48:53 -08:00
Vadim Fedorenko
6e17474aa9 net: fib: restore ECMP balance from loopback
Preference of nexthop with source address broke ECMP for packets with
source addresses which are not in the broadcast domain, but rather added
to loopback/dummy interfaces. Original behaviour was to balance over
nexthops while now it uses the latest nexthop from the group. To fix the
issue introduce next hop scoring system where next hops with source
address equal to requested will always have higher priority.

For the case with 198.51.100.1/32 assigned to dummy0 and routed using
192.0.2.0/24 and 203.0.113.0/24 networks:

2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether d6:54:8a:ff:78:f5 brd ff:ff:ff:ff:ff:ff
    inet 198.51.100.1/32 scope global dummy0
       valid_lft forever preferred_lft forever
7: veth1@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 06:ed:98:87:6d:8a brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.0.2.2/24 scope global veth1
       valid_lft forever preferred_lft forever
    inet6 fe80::4ed:98ff:fe87:6d8a/64 scope link proto kernel_ll
       valid_lft forever preferred_lft forever
9: veth3@if8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether ae:75:23:38:a0:d2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 203.0.113.2/24 scope global veth3
       valid_lft forever preferred_lft forever
    inet6 fe80::ac75:23ff:fe38:a0d2/64 scope link proto kernel_ll
       valid_lft forever preferred_lft forever

~ ip ro list:
default
	nexthop via 192.0.2.1 dev veth1 weight 1
	nexthop via 203.0.113.1 dev veth3 weight 1
192.0.2.0/24 dev veth1 proto kernel scope link src 192.0.2.2
203.0.113.0/24 dev veth3 proto kernel scope link src 203.0.113.2

before:
   for i in {1..255} ; do ip ro get 10.0.0.$i; done | grep veth | awk ' {print $(NF-2)}' | sort | uniq -c:
    255 veth3

after:
   for i in {1..255} ; do ip ro get 10.0.0.$i; done | grep veth | awk ' {print $(NF-2)}' | sort | uniq -c:
    122 veth1
    133 veth3

Fixes: 32607a332c ("ipv4: prefer multipath nexthop that matches source address")
Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20251221192639.3911901-1-vadim.fedorenko@linux.dev
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-30 11:07:38 +01:00
Ido Schimmel
ac782f4e3b ipv4: Fix reference count leak when using error routes with nexthop objects
When a nexthop object is deleted, it is marked as dead and then
fib_table_flush() is called to flush all the routes that are using the
dead nexthop.

The current logic in fib_table_flush() is to only flush error routes
(e.g., blackhole) when it is called as part of network namespace
dismantle (i.e., with flush_all=true). Therefore, error routes are not
flushed when their nexthop object is deleted:

 # ip link add name dummy1 up type dummy
 # ip nexthop add id 1 dev dummy1
 # ip route add 198.51.100.1/32 nhid 1
 # ip route add blackhole 198.51.100.2/32 nhid 1
 # ip nexthop del id 1
 # ip route show
 blackhole 198.51.100.2 nhid 1 dev dummy1

As such, they keep holding a reference on the nexthop object which in
turn holds a reference on the nexthop device, resulting in a reference
count leak:

 # ip link del dev dummy1
 [   70.516258] unregister_netdevice: waiting for dummy1 to become free. Usage count = 2

Fix by flushing error routes when their nexthop is marked as dead.

IPv6 does not suffer from this problem.

Fixes: 493ced1ac4 ("ipv4: Allow routes to use nexthop objects")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Closes: https://lore.kernel.org/netdev/d943f806-4da6-4970-ac28-b9373b0e63ac@I-love.SAKURA.ne.jp/
Reported-by: syzbot+881d65229ca4f9ae8c84@syzkaller.appspotmail.com
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20251221144829.197694-1-idosch@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-30 10:39:22 +01:00
Frode Nordahl
35ddf66c65 erspan: Initialize options_len before referencing options.
The struct ip_tunnel_info has a flexible array member named
options that is protected by a counted_by(options_len)
attribute.

The compiler will use this information to enforce runtime bounds
checking deployed by FORTIFY_SOURCE string helpers.

As laid out in the GCC documentation, the counter must be
initialized before the first reference to the flexible array
member.

After scanning through the files that use struct ip_tunnel_info
and also refer to options or options_len, it appears the normal
case is to use the ip_tunnel_info_opts_set() helper.

Said helper would initialize options_len properly before copying
data into options, however in the GRE ERSPAN code a partial
update is done, preventing the use of the helper function.

Before this change the handling of ERSPAN traffic in GRE tunnels
would cause a kernel panic when the kernel is compiled with
GCC 15+ and having FORTIFY_SOURCE configured:

memcpy: detected buffer overflow: 4 byte write of buffer size 0

Call Trace:
 <IRQ>
 __fortify_panic+0xd/0xf
 erspan_rcv.cold+0x68/0x83
 ? ip_route_input_slow+0x816/0x9d0
 gre_rcv+0x1b2/0x1c0
 gre_rcv+0x8e/0x100
 ? raw_v4_input+0x2a0/0x2b0
 ip_protocol_deliver_rcu+0x1ea/0x210
 ip_local_deliver_finish+0x86/0x110
 ip_local_deliver+0x65/0x110
 ? ip_rcv_finish_core+0xd6/0x360
 ip_rcv+0x186/0x1a0

Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-counted_005fby-variable-attribute
Reported-at: https://launchpad.net/bugs/2129580
Fixes: bb5e62f2d5 ("net: Add options as a flexible array to struct ip_tunnel_info")
Signed-off-by: Frode Nordahl <fnordahl@ubuntu.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20251213101338.4693-1-fnordahl@ubuntu.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-23 09:21:00 +01:00
Jakub Kicinski
006a5035b4 inet: frags: flush pending skbs in fqdir_pre_exit()
We have been seeing occasional deadlocks on pernet_ops_rwsem since
September in NIPA. The stuck task was usually modprobe (often loading
a driver like ipvlan), trying to take the lock as a Writer.
lockdep does not track readers for rwsems so the read wasn't obvious
from the reports.

On closer inspection the Reader holding the lock was conntrack looping
forever in nf_conntrack_cleanup_net_list(). Based on past experience
with occasional NIPA crashes I looked thru the tests which run before
the crash and noticed that the crash follows ip_defrag.sh. An immediate
red flag. Scouring thru (de)fragmentation queues reveals skbs sitting
around, holding conntrack references.

The problem is that since conntrack depends on nf_defrag_ipv6,
nf_defrag_ipv6 will load first. Since nf_defrag_ipv6 loads first its
netns exit hooks run _after_ conntrack's netns exit hook.

Flush all fragment queue SKBs during fqdir_pre_exit() to release
conntrack references before conntrack cleanup runs. Also flush
the queues in timer expiry handlers when they discover fqdir->dead
is set, in case packet sneaks in while we're running the pre_exit
flush.

The commit under Fixes is not exactly the culprit, but I think
previously the timer firing would eventually unblock the spinning
conntrack.

Fixes: d5dd88794a ("inet: fix various use-after-free in defrags units")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251207010942.1672972-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-10 01:15:27 -08:00
Jakub Kicinski
1231eec699 inet: frags: add inet_frag_queue_flush()
Instead of exporting inet_frag_rbtree_purge() which requires that
caller takes care of memory accounting, add a new helper. We will
need to call it from a few places in the next patch.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251207010942.1672972-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-10 01:15:27 -08:00
Jakub Kicinski
8ef522c8a5 inet: frags: avoid theoretical race in ip_frag_reinit()
In ip_frag_reinit() we want to move the frag timeout timer into
the future. If the timer fires in the meantime we inadvertently
scheduled it again, and since the timer assumes a ref on frag_queue
we need to acquire one to balance things out.

This is technically racy, we should have acquired the reference
_before_ we touch the timer, it may fire again before we take the ref.
Avoid this entire dance by using mod_timer_pending() which only modifies
the timer if its pending (and which exists since Linux v2.6.30)

Note that this was the only place we ever took a ref on frag_queue
since Eric's conversion to RCU. So we could potentially replace
the whole refcnt field with an atomic flag and a bit more RCU.

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251207010942.1672972-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-10 01:15:27 -08:00
Jianbo Liu
3d5221af9c xfrm: Fix inner mode lookup in tunnel mode GSO segmentation
Commit 61fafbee6c ("xfrm: Determine inner GSO type from packet inner
protocol") attempted to fix GSO segmentation by reading the inner
protocol from XFRM_MODE_SKB_CB(skb)->protocol. This was incorrect
because the field holds the inner L4 protocol (TCP/UDP) instead of the
required tunnel protocol. Also, the memory location (shared by
XFRM_SKB_CB(skb) which could be overwritten by xfrm_replay_overflow())
is prone to corruption. This combination caused the kernel to select
the wrong inner mode and get the wrong address family.

The correct value is in xfrm_offload(skb)->proto, which is set from
the outer tunnel header's protocol field by esp[4|6]_gso_encap(). It
is initialized by xfrm[4|6]_tunnel_encap_add() to either IPPROTO_IPIP
or IPPROTO_IPV6, using xfrm_af2proto() and correctly reflects the
inner packet's address family.

Fixes: 61fafbee6c ("xfrm: Determine inner GSO type from packet inner protocol")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2025-12-04 09:54:53 +01:00
Thorsten Blum
ff736a2861 net: ipconfig: Replace strncpy with strscpy in ic_proto_name
strncpy() is deprecated [1] for NUL-terminated destination buffers
because it does not guarantee NUL termination. Replace it with strscpy()
to ensure the destination buffer is always NUL-terminated and to avoid
any additional NUL padding.

Although the identifier buffer has 252 usable bytes, strncpy() copied
only up to 251 bytes to the zero-initialized buffer, relying on the last
byte to act as an implicit NUL terminator. Switching to strscpy() avoids
this implicit behavior and does not use magic numbers.

The source string is also NUL-terminated and satisfies the
__must_be_cstr() requirement of strscpy().

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://patch.msgid.link/20251126220804.102160-2-thorsten.blum@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-28 20:19:16 -08:00
Jakub Kicinski
840a64710e Merge tag 'nf-next-25-11-28' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next
Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following batch contains Netfilter updates for net-next:

0) Add sanity check for maximum encapsulations in bridge vlan,
   reported by the new AI robot.

1) Move the flowtable path discovery code to its own file, the
   nft_flow_offload.c mixes the nf_tables evaluation with the path
   discovery logic, just split this in two for clarity.

2) Consolidate flowtable xmit path by using dev_queue_xmit() and the
   real device behind the layer 2 vlan/pppoe device. This allows to
   inline encapsulation. After this update, hw_ifidx can be removed
   since both ifidx and hw_ifidx now point to the same device.

3) Support for IPIP encapsulation in the flowtable, extend selftest
   to cover for this new layer 3 offload, from Lorenzo Bianconi.

4) Push down the skb into the conncount API to fix duplicates in the
   conncount list for packets with non-confirmed conntrack entries,
   this is due to an optimization introduced in d265929930
   ("netfilter: nf_conncount: reduce unnecessary GC").
   From Fernando Fernandez Mancera.

5) In conncount, disable BH when performing garbage collection
   to consolidate existing behaviour in the conncount API, also
   from Fernando.

6) A matching packet with a confirmed conntrack invokes GC if
   conncount reaches the limit in an attempt to release slots.
   This allows the existing extensions to be used for real conntrack
   counting, not just limiting new connections, from Fernando.

7) Support for updating ct count objects in nf_tables, from Fernando.

8) Extend nft_flowtables.sh selftest to send IPv6 TCP traffic,
   from Lorenzo Bianconi.

9) Fixes for UAPI kernel-doc documentation, from Randy Dunlap.

* tag 'nf-next-25-11-28' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next:
  netfilter: nf_tables: improve UAPI kernel-doc comments
  netfilter: ip6t_srh: fix UAPI kernel-doc comments format
  selftests: netfilter: nft_flowtable.sh: Add the capability to send IPv6 TCP traffic
  netfilter: nft_connlimit: add support to object update operation
  netfilter: nft_connlimit: update the count if add was skipped
  netfilter: nf_conncount: make nf_conncount_gc_list() to disable BH
  netfilter: nf_conncount: rework API to use sk_buff directly
  selftests: netfilter: nft_flowtable.sh: Add IPIP flowtable selftest
  netfilter: flowtable: Add IPIP tx sw acceleration
  netfilter: flowtable: Add IPIP rx sw acceleration
  netfilter: flowtable: use tuple address to calculate next hop
  netfilter: flowtable: remove hw_ifidx
  netfilter: flowtable: inline pppoe encapsulation in xmit path
  netfilter: flowtable: inline vlan encapsulation in xmit path
  netfilter: flowtable: consolidate xmit path
  netfilter: flowtable: move path discovery infrastructure to its own file
  netfilter: flowtable: check for maximum number of encapsulations in bridge vlan
====================

Link: https://patch.msgid.link/20251128002345.29378-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-28 20:08:39 -08:00
Byungchul Park
df59bb5b9a netmem, devmem, tcp: access pp fields through @desc in net_iov
Convert all the legacy code directly accessing the pp fields in net_iov
to access them through @desc in net_iov.

Signed-off-by: Byungchul Park <byungchul@sk.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-27 17:41:51 -08:00
Lorenzo Bianconi
ab427db178 netfilter: flowtable: Add IPIP rx sw acceleration
Introduce sw acceleration for rx path of IPIP tunnels relying on the
netfilter flowtable infrastructure. Subsequent patches will add sw
acceleration for IPIP tunnels tx path.
This series introduces basic infrastructure to accelerate other tunnel
types (e.g. IP6IP6).
IPIP rx sw acceleration can be tested running the following scenario where
the traffic is forwarded between two NICs (eth0 and eth1) and an IPIP
tunnel is used to access a remote site (using eth1 as the underlay device):

ETH0 -- TUN0 <==> ETH1 -- [IP network] -- TUN1 (192.168.100.2)

$ip addr show
6: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:00:22:33:11:55 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.2/24 scope global eth0
       valid_lft forever preferred_lft forever
7: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:11:22:33:11:55 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.1/24 scope global eth1
       valid_lft forever preferred_lft forever
8: tun0@NONE: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1480 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ipip 192.168.1.1 peer 192.168.1.2
    inet 192.168.100.1/24 scope global tun0
       valid_lft forever preferred_lft forever

$ip route show
default via 192.168.100.2 dev tun0
192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.2
192.168.1.0/24 dev eth1 proto kernel scope link src 192.168.1.1
192.168.100.0/24 dev tun0 proto kernel scope link src 192.168.100.1

$nft list ruleset
table inet filter {
        flowtable ft {
                hook ingress priority filter
                devices = { eth0, eth1 }
        }

        chain forward {
                type filter hook forward priority filter; policy accept;
                meta l4proto { tcp, udp } flow add @ft
        }
}

Reproducing the scenario described above using veths I got the following
results:
- TCP stream received from the IPIP tunnel:
  - net-next: (baseline)		~ 71Gbps
  - net-next + IPIP flowtbale support:	~101Gbps

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2025-11-28 00:00:38 +00:00
Eric Dumazet
9a5e5334ad tcp: remove icsk->icsk_retransmit_timer
Now sk->sk_timer is no longer used by TCP keepalive, we can use
its storage for TCP and MPTCP retransmit timers for better
cache locality.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:28:29 -08:00
Eric Dumazet
08dfe37023 tcp: introduce icsk->icsk_keepalive_timer
sk->sk_timer has been used for TCP keepalives.

Keepalive timers are not in fast path, we want to use sk->sk_timer
storage for retransmit timers, for better cache locality.

Create icsk->icsk_keepalive_timer and change keepalive
code to no longer use sk->sk_timer.

Added space is reclaimed in the following patch.

This includes changes to MPTCP, which was also using sk_timer.

Alias icsk->mptcp_tout_timer and icsk->icsk_keepalive_timer
for inet_sk_diag_fill() sake.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:28:29 -08:00
Eric Dumazet
3a6e8fd0bf tcp: rename icsk_timeout() to tcp_timeout_expires()
In preparation of sk->tcp_timeout_timer introduction,
rename icsk_timeout() helper and change its argument to plain
'const struct sock *sk'.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:28:28 -08:00
Asbjørn Sloth Tønnesen
68e83f3472 tools: ynl-gen: add regeneration comment
Add a comment on regeneration to the generated files.

The comment is placed after the YNL-GEN line[1], as to not interfere
with ynl-regen.sh's detection logic.

[1] and after the optional YNL-ARG line.

Link: https://lore.kernel.org/r/aR5m174O7pklKrMR@zx2c4.com/
Suggested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251120174429.390574-3-ast@fiberby.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:20:42 -08:00
Paolo Abeni
075b19c211 net: factor-out _sk_charge() helper
Move out of __inet_accept() the code dealing charging newly
accepted socket to memcg. MPTCP will soon use it to on a per
subflow basis, in different contexts.

No functional changes intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Geliang Tang <geliang@kernel.org>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-1-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:40 -08:00
Eric Dumazet
ecfea98b7d tcp: add net.ipv4.tcp_rcvbuf_low_rtt
This is a follow up of commit aa251c8463 ("tcp: fix too slow
tcp_rcvbuf_grow() action") which brought again the issue that I tried
to fix in commit 65c5287892 ("tcp: fix sk_rcvbuf overshoot")

We also recently increased tcp_rmem[2] to 32 MB in commit 572be9bf9d
("tcp: increase tcp_rmem[2] to 32 MB")

Idea of this patch is to not let tcp_rcvbuf_grow() grow sk->sk_rcvbuf
too fast for small RTT flows. If sk->sk_rcvbuf is too big, this can
force NIC driver to not recycle pages from their page pool, and also
can cause cache evictions for DDIO enabled cpus/NIC, as receivers
are usually slower than senders.

Add net.ipv4.tcp_rcvbuf_low_rtt sysctl, set by default to 1000 usec (1 ms)

If RTT if smaller than the sysctl value, use the RTT/tcp_rcvbuf_low_rtt
ratio to control sk_rcvbuf inflation.

Tested:

Pair of hosts with a 200Gbit IDPF NIC. Using netperf/netserver

Client initiates 8 TCP bulk flows, asking netserver to use CPU #10 only.

super_netperf 8 -H server -T,10 -l 30

On server, use perf -e tcp:tcp_rcvbuf_grow while test is running.

Before:

sysctl -w net.ipv4.tcp_rcvbuf_low_rtt=1
perf record -a -e tcp:tcp_rcvbuf_grow sleep 30 ; perf script|tail -20|cut -c30-230
 1153.051201: tcp:tcp_rcvbuf_grow: time=398 rtt_us=382 copied=6905856 inq=180224 space=6115328 ooo=0 scaling_ratio=240 rcvbuf=27666235 rcv_ssthresh=25878235 window_clamp=25937095 rcv_wnd=25600000 famil
 1153.138752: tcp:tcp_rcvbuf_grow: time=446 rtt_us=413 copied=5529600 inq=180224 space=4505600 ooo=0 scaling_ratio=240 rcvbuf=23068672 rcv_ssthresh=21571860 window_clamp=21626880 rcv_wnd=21286912 famil
 1153.361484: tcp:tcp_rcvbuf_grow: time=415 rtt_us=380 copied=7061504 inq=204800 space=6725632 ooo=0 scaling_ratio=240 rcvbuf=27666235 rcv_ssthresh=25878235 window_clamp=25937095 rcv_wnd=25600000 famil
 1153.457642: tcp:tcp_rcvbuf_grow: time=483 rtt_us=421 copied=5885952 inq=720896 space=4407296 ooo=0 scaling_ratio=240 rcvbuf=23763511 rcv_ssthresh=22223271 window_clamp=22278291 rcv_wnd=21430272 famil
 1153.466002: tcp:tcp_rcvbuf_grow: time=308 rtt_us=281 copied=3244032 inq=180224 space=2883584 ooo=0 scaling_ratio=240 rcvbuf=44854314 rcv_ssthresh=41992059 window_clamp=42050919 rcv_wnd=41713664 famil
 1153.747792: tcp:tcp_rcvbuf_grow: time=394 rtt_us=332 copied=4460544 inq=585728 space=3063808 ooo=0 scaling_ratio=240 rcvbuf=44854314 rcv_ssthresh=41992059 window_clamp=42050919 rcv_wnd=41373696 famil
 1154.260747: tcp:tcp_rcvbuf_grow: time=652 rtt_us=226 copied=10977280 inq=737280 space=9486336 ooo=0 scaling_ratio=240 rcvbuf=31165538 rcv_ssthresh=29197743 window_clamp=29217691 rcv_wnd=28368896 fami
 1154.375019: tcp:tcp_rcvbuf_grow: time=461 rtt_us=443 copied=7573504 inq=507904 space=6856704 ooo=0 scaling_ratio=240 rcvbuf=27666235 rcv_ssthresh=25878235 window_clamp=25937095 rcv_wnd=25288704 famil
 1154.463072: tcp:tcp_rcvbuf_grow: time=494 rtt_us=408 copied=7983104 inq=200704 space=7065600 ooo=0 scaling_ratio=240 rcvbuf=27666235 rcv_ssthresh=25878235 window_clamp=25937095 rcv_wnd=25579520 famil
 1154.474658: tcp:tcp_rcvbuf_grow: time=507 rtt_us=459 copied=5586944 inq=540672 space=4718592 ooo=0 scaling_ratio=240 rcvbuf=17852266 rcv_ssthresh=16692999 window_clamp=16736499 rcv_wnd=16056320 famil
 1154.584657: tcp:tcp_rcvbuf_grow: time=494 rtt_us=427 copied=8126464 inq=204800 space=7782400 ooo=0 scaling_ratio=240 rcvbuf=27666235 rcv_ssthresh=25878235 window_clamp=25937095 rcv_wnd=25600000 famil
 1154.702117: tcp:tcp_rcvbuf_grow: time=480 rtt_us=406 copied=5734400 inq=180224 space=5349376 ooo=0 scaling_ratio=240 rcvbuf=23068672 rcv_ssthresh=21571860 window_clamp=21626880 rcv_wnd=21286912 famil
 1155.941595: tcp:tcp_rcvbuf_grow: time=717 rtt_us=670 copied=11042816 inq=3784704 space=7159808 ooo=0 scaling_ratio=240 rcvbuf=19581357 rcv_ssthresh=18333222 window_clamp=18357522 rcv_wnd=14614528 fam
 1156.384735: tcp:tcp_rcvbuf_grow: time=529 rtt_us=473 copied=9011200 inq=180224 space=7258112 ooo=0 scaling_ratio=240 rcvbuf=19581357 rcv_ssthresh=18333222 window_clamp=18357522 rcv_wnd=18018304 famil
 1157.821676: tcp:tcp_rcvbuf_grow: time=529 rtt_us=272 copied=8224768 inq=602112 space=6545408 ooo=0 scaling_ratio=240 rcvbuf=67000000 rcv_ssthresh=62793576 window_clamp=62812500 rcv_wnd=62115840 famil
 1158.906379: tcp:tcp_rcvbuf_grow: time=710 rtt_us=445 copied=11845632 inq=540672 space=10240000 ooo=0 scaling_ratio=240 rcvbuf=31165538 rcv_ssthresh=29205935 window_clamp=29217691 rcv_wnd=28536832 fam
 1164.600160: tcp:tcp_rcvbuf_grow: time=841 rtt_us=430 copied=12976128 inq=1290240 space=11304960 ooo=0 scaling_ratio=240 rcvbuf=31165538 rcv_ssthresh=29212591 window_clamp=29217691 rcv_wnd=27856896 fa
 1165.163572: tcp:tcp_rcvbuf_grow: time=845 rtt_us=800 copied=12632064 inq=540672 space=7921664 ooo=0 scaling_ratio=240 rcvbuf=27666235 rcv_ssthresh=25912795 window_clamp=25937095 rcv_wnd=25260032 fami
 1165.653464: tcp:tcp_rcvbuf_grow: time=388 rtt_us=309 copied=4493312 inq=180224 space=3874816 ooo=0 scaling_ratio=240 rcvbuf=44854314 rcv_ssthresh=41995899 window_clamp=42050919 rcv_wnd=41713664 famil
 1166.651211: tcp:tcp_rcvbuf_grow: time=556 rtt_us=553 copied=6328320 inq=540672 space=5554176 ooo=0 scaling_ratio=240 rcvbuf=23068672 rcv_ssthresh=21571860 window_clamp=21626880 rcv_wnd=20946944 famil

After:

sysctl -w net.ipv4.tcp_rcvbuf_low_rtt=1000
perf record -a -e tcp:tcp_rcvbuf_grow sleep 30 ; perf script|tail -20|cut -c30-230
 1457.053149: tcp:tcp_rcvbuf_grow: time=128 rtt_us=24 copied=1441792 inq=40960 space=1269760 ooo=0 scaling_ratio=240 rcvbuf=2960741 rcv_ssthresh=2605474 window_clamp=2775694 rcv_wnd=2568192 family=AF_I
 1458.000778: tcp:tcp_rcvbuf_grow: time=128 rtt_us=31 copied=1441792 inq=24576 space=1400832 ooo=0 scaling_ratio=240 rcvbuf=3060163 rcv_ssthresh=2810042 window_clamp=2868902 rcv_wnd=2674688 family=AF_I
 1458.088059: tcp:tcp_rcvbuf_grow: time=190 rtt_us=110 copied=3227648 inq=385024 space=2781184 ooo=0 scaling_ratio=240 rcvbuf=6728240 rcv_ssthresh=6252705 window_clamp=6307725 rcv_wnd=5799936 family=AF
 1458.148549: tcp:tcp_rcvbuf_grow: time=232 rtt_us=129 copied=3956736 inq=237568 space=2842624 ooo=0 scaling_ratio=240 rcvbuf=6731333 rcv_ssthresh=6252705 window_clamp=6310624 rcv_wnd=5918720 family=AF
 1458.466861: tcp:tcp_rcvbuf_grow: time=193 rtt_us=83 copied=2949120 inq=180224 space=2457600 ooo=0 scaling_ratio=240 rcvbuf=5751438 rcv_ssthresh=5357689 window_clamp=5391973 rcv_wnd=5054464 family=AF_
 1458.775476: tcp:tcp_rcvbuf_grow: time=257 rtt_us=127 copied=4304896 inq=352256 space=3346432 ooo=0 scaling_ratio=240 rcvbuf=8067131 rcv_ssthresh=7523275 window_clamp=7562935 rcv_wnd=7061504 family=AF
 1458.776631: tcp:tcp_rcvbuf_grow: time=200 rtt_us=96 copied=3260416 inq=143360 space=2768896 ooo=0 scaling_ratio=240 rcvbuf=6397256 rcv_ssthresh=5938567 window_clamp=5997427 rcv_wnd=5828608 family=AF_
 1459.707973: tcp:tcp_rcvbuf_grow: time=215 rtt_us=96 copied=2506752 inq=163840 space=1388544 ooo=0 scaling_ratio=240 rcvbuf=3068867 rcv_ssthresh=2768282 window_clamp=2877062 rcv_wnd=2555904 family=AF_
 1460.246494: tcp:tcp_rcvbuf_grow: time=231 rtt_us=80 copied=3756032 inq=204800 space=3117056 ooo=0 scaling_ratio=240 rcvbuf=7288091 rcv_ssthresh=6773725 window_clamp=6832585 rcv_wnd=6471680 family=AF_
 1460.714596: tcp:tcp_rcvbuf_grow: time=270 rtt_us=110 copied=4714496 inq=311296 space=3719168 ooo=0 scaling_ratio=240 rcvbuf=8957739 rcv_ssthresh=8339020 window_clamp=8397880 rcv_wnd=7933952 family=AF
 1462.029977: tcp:tcp_rcvbuf_grow: time=101 rtt_us=19 copied=1105920 inq=40960 space=1036288 ooo=0 scaling_ratio=240 rcvbuf=2338970 rcv_ssthresh=2091684 window_clamp=2192784 rcv_wnd=1986560 family=AF_I
 1462.802385: tcp:tcp_rcvbuf_grow: time=89 rtt_us=45 copied=1069056 inq=0 space=1064960 ooo=0 scaling_ratio=240 rcvbuf=2338970 rcv_ssthresh=2091684 window_clamp=2192784 rcv_wnd=2035712 family=AF_INET6
 1462.918648: tcp:tcp_rcvbuf_grow: time=105 rtt_us=33 copied=1441792 inq=180224 space=1069056 ooo=0 scaling_ratio=240 rcvbuf=2383282 rcv_ssthresh=2091684 window_clamp=2234326 rcv_wnd=1896448 family=AF_
 1463.222533: tcp:tcp_rcvbuf_grow: time=273 rtt_us=144 copied=4603904 inq=385024 space=3469312 ooo=0 scaling_ratio=240 rcvbuf=8422564 rcv_ssthresh=7891053 window_clamp=7896153 rcv_wnd=7409664 family=AF
 1466.519312: tcp:tcp_rcvbuf_grow: time=130 rtt_us=23 copied=1343488 inq=0 space=1261568 ooo=0 scaling_ratio=240 rcvbuf=2780158 rcv_ssthresh=2493778 window_clamp=2606398 rcv_wnd=2494464 family=AF_INET6
 1466.681003: tcp:tcp_rcvbuf_grow: time=128 rtt_us=21 copied=1441792 inq=12288 space=1343488 ooo=0 scaling_ratio=240 rcvbuf=2932027 rcv_ssthresh=2578555 window_clamp=2748775 rcv_wnd=2568192 family=AF_I
 1470.689959: tcp:tcp_rcvbuf_grow: time=255 rtt_us=122 copied=3932160 inq=204800 space=3551232 ooo=0 scaling_ratio=240 rcvbuf=8182038 rcv_ssthresh=7647384 window_clamp=7670660 rcv_wnd=7442432 family=AF
 1471.754154: tcp:tcp_rcvbuf_grow: time=188 rtt_us=95 copied=2138112 inq=577536 space=1429504 ooo=0 scaling_ratio=240 rcvbuf=3113650 rcv_ssthresh=2806426 window_clamp=2919046 rcv_wnd=2248704 family=AF_
 1476.813542: tcp:tcp_rcvbuf_grow: time=269 rtt_us=99 copied=3088384 inq=180224 space=2564096 ooo=0 scaling_ratio=240 rcvbuf=6219470 rcv_ssthresh=5771893 window_clamp=5830753 rcv_wnd=5509120 family=AF_
 1477.738309: tcp:tcp_rcvbuf_grow: time=166 rtt_us=54 copied=1777664 inq=180224 space=1417216 ooo=0 scaling_ratio=240 rcvbuf=3117118 rcv_ssthresh=2874958 window_clamp=2922298 rcv_wnd=2613248 family=AF_

We can see sk_rcvbuf values are much smaller, and that rtt_us (estimation of rtt
from a receiver point of view) is kept small, instead of being bloated.

No difference in throughput.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Tested-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/20251119084813.3684576-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-20 17:44:23 -08:00
Jakub Kicinski
9e203721ec Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.18-rc7).

No conflicts, adjacent changes:

tools/testing/selftests/net/af_unix/Makefile
  e1bb28bf13 ("selftest: af_unix: Add test for SO_PEEK_OFF.")
  45a1cd8346 ("selftests: af_unix: Add tests for ECONNRESET and EOF semantics")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-20 09:13:26 -08:00
Kuniyuki Iwashima
932478bf9f tcp: Don't reinitialise tw->tw_transparent in tcp_time_wait().
tw->tw_transparent is initialised twice in inet_twsk_alloc()
and tcp_time_wait().

Let's remove the latter.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20251118000445.4091280-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-18 18:00:38 -08:00
Jakub Kicinski
c3995fc1a8 Merge tag 'ipsec-2025-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec
Steffen Klassert says:

====================
pull request (net): ipsec 2025-11-18

1) Misc fixes for xfrm_state creation/modification/deletion.
   Patchset from Sabrina Dubroca.

2) Fix inner packet family determination for xfrm offloads.
   From Jianbo Liu.

3) Don't push locally generated packets directly to L2 tunnel
   mode offloading, they still need processing from the standard
   xfrm path. From Jianbo Liu.

4) Fix memory leaks in xfrm_add_acquire for policy offloads and policy
   security contexts. From Zilin Guan.

* tag 'ipsec-2025-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
  xfrm: fix memory leak in xfrm_add_acquire()
  xfrm: Prevent locally generated packets from direct output in tunnel mode
  xfrm: Determine inner GSO type from packet inner protocol
  xfrm: Check inner packet family directly from skb_dst
  xfrm: check all hash buckets for leftover states during netns deletion
  xfrm: set err and extack on failure to create pcpu SA
  xfrm: call xfrm_dev_state_delete when xfrm_state_migrate fails to add the state
  xfrm: make state as DEAD before final put when migrate fails
  xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added
  xfrm: drop SA reference in xfrm_state_update if dir doesn't match
====================

Link: https://patch.msgid.link/20251118085344.2199815-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-18 17:58:44 -08:00
Eric Dumazet
ca412f25d6 tcp: reduce tcp_comp_sack_slack_ns default value to 10 usec
net.ipv4.tcp_comp_sack_slack_ns current default value is too high.

When a flow has many drops (1 % or more), and small RTT, adding 100 usec
before sending SACK stalls the sender relying on getting SACK
fast enough to keep the pipe busy.

Decrease the default to 10 usec.

This is orthogonal to Congestion Control heuristics to determine
if drops are caused by congestion or not.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251114135141.3810964-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-17 17:02:43 -08:00
Eric Dumazet
6d650ae928 tcp: gro: inline tcp_gro_pull_header()
tcp_gro_pull_header() is used in GRO fast path, inline it.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251113140358.58242-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-14 18:00:08 -08:00
Jakub Kicinski
c99ebb6132 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.18-rc6).

No conflicts, adjacent changes in:

drivers/net/phy/micrel.c
  96a9178a29 ("net: phy: micrel: lan8814 fix reset of the QSGMII interface")
  61b7ade9ba ("net: phy: micrel: Add support for non PTP SKUs for lan8814")

and a trivial one in tools/testing/selftests/drivers/net/Makefile.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-13 12:35:38 -08:00
Chuang Wang
ac1499fcd4 ipv4: route: Prevent rt_bind_exception() from rebinding stale fnhe
The sit driver's packet transmission path calls: sit_tunnel_xmit() ->
update_or_create_fnhe(), which lead to fnhe_remove_oldest() being called
to delete entries exceeding FNHE_RECLAIM_DEPTH+random.

The race window is between fnhe_remove_oldest() selecting fnheX for
deletion and the subsequent kfree_rcu(). During this time, the
concurrent path's __mkroute_output() -> find_exception() can fetch the
soon-to-be-deleted fnheX, and rt_bind_exception() then binds it with a
new dst using a dst_hold(). When the original fnheX is freed via RCU,
the dst reference remains permanently leaked.

CPU 0                             CPU 1
__mkroute_output()
  find_exception() [fnheX]
                                  update_or_create_fnhe()
                                    fnhe_remove_oldest() [fnheX]
  rt_bind_exception() [bind dst]
                                  RCU callback [fnheX freed, dst leak]

This issue manifests as a device reference count leak and a warning in
dmesg when unregistering the net device:

  unregister_netdevice: waiting for sitX to become free. Usage count = N

Ido Schimmel provided the simple test validation method [1].

The fix clears 'oldest->fnhe_daddr' before calling fnhe_flush_routes().
Since rt_bind_exception() checks this field, setting it to zero prevents
the stale fnhe from being reused and bound to a new dst just before it
is freed.

[1]
ip netns add ns1
ip -n ns1 link set dev lo up
ip -n ns1 address add 192.0.2.1/32 dev lo
ip -n ns1 link add name dummy1 up type dummy
ip -n ns1 route add 192.0.2.2/32 dev dummy1
ip -n ns1 link add name gretap1 up arp off type gretap \
    local 192.0.2.1 remote 192.0.2.2
ip -n ns1 route add 198.51.0.0/16 dev gretap1
taskset -c 0 ip netns exec ns1 mausezahn gretap1 \
    -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
taskset -c 2 ip netns exec ns1 mausezahn gretap1 \
    -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
sleep 10
ip netns pids ns1 | xargs kill
ip netns del ns1

Cc: stable@vger.kernel.org
Fixes: 67d6d681e1 ("ipv4: make exception cache less predictible")
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251111064328.24440-1-nashuiliang@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-12 06:46:36 -08:00
D. Wythe
15f295f556 net/smc: bpf: Introduce generic hook for handshake flow
The introduction of IPPROTO_SMC enables eBPF programs to determine
whether to use SMC based on the context of socket creation, such as
network namespaces, PID and comm name, etc.

As a subsequent enhancement, to introduce a new generic hook that
allows decisions on whether to use SMC or not at runtime, including
but not limited to local/remote IP address or ports.

User can write their own implememtion via bpf_struct_ops now to choose
whether to use SMC or not before TCP 3rd handshake to be comleted.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://patch.msgid.link/20251107035632.115950-3-alibuda@linux.alibaba.com
2025-11-10 11:19:41 -08:00
Eric Dumazet
416dd649f3 tcp: add net.ipv4.tcp_comp_sack_rtt_percent
TCP SACK compression has been added in 2018 in commit
5d9f4262b7 ("tcp: add SACK compression").

It is working great for WAN flows (with large RTT).
Wifi in particular gets a significant boost _when_ ACK are suppressed.

Add a new sysctl so that we can tune the very conservative 5 % value
that has been used so far in this formula, so that small RTT flows
can benefit from this feature.

delay = min ( 5 % of RTT, 1 ms)

This patch adds new tcp_comp_sack_rtt_percent sysctl
to ease experiments and tuning.

Given that we cap the delay to 1ms (tcp_comp_sack_delay_ns sysctl),
set the default value to 33 %.

Quoting Neal Cardwell ( https://lore.kernel.org/netdev/CADVnQymZ1tFnEA1Q=vtECs0=Db7zHQ8=+WCQtnhHFVbEOzjVnQ@mail.gmail.com/ )

The rationale for 33% is basically to try to facilitate pipelining,
where there are always at least 3 ACKs and 3 GSO/TSO skbs per SRTT, so
that the path can maintain a budget for 3 full-sized GSO/TSO skbs "in
flight" at all times:

+ 1 skb in the qdisc waiting to be sent by the NIC next
+ 1 skb being sent by the NIC (being serialized by the NIC out onto the wire)
+ 1 skb being received and aggregated by the receiver machine's
aggregation mechanism (some combination of LRO, GRO, and sack
compression)

Note that this is basically the same magic number (3) and the same
rationales as:

(a) tcp_tso_should_defer() ensuring that we defer sending data for no
longer than cwnd/tcp_tso_win_divisor (where tcp_tso_win_divisor = 3),
and
(b) bbr_quantization_budget() ensuring that cwnd is at least 3 GSO/TSO
skbs to maintain pipelining and full throughput at low RTTs

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251106115236.3450026-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07 18:41:44 -08:00
Kuniyuki Iwashima
207ce0f6bc tcp: Remove timeout arg from reqsk_timeout().
reqsk_timeout() is always called with @timeout being TCP_RTO_MAX.

Let's remove the arg.

As a prep for the next patch, reqsk_timeout() is moved to tcp.h
and renamed to tcp_reqsk_timeout().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251106003357.273403-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07 18:05:26 -08:00
Kuniyuki Iwashima
6fbf648d5c tcp: Remove redundant init for req->num_timeout.
Commit 5903123f66 ("tcp: Use BPF timeout setting for SYN ACK
RTO") introduced req->timeout and initialised it in 3 places:

  1. reqsk_alloc() sets 0
  2. inet_reqsk_alloc() sets TCP_TIMEOUT_INIT
  3. tcp_conn_request() sets tcp_timeout_init()

1. has been always redundant as 2. overwrites it immediately.

2. was necessary for TFO SYN+ACK but is no longer needed after
commit 8ea731d4c2 ("tcp: Make SYN ACK RTO tunable by BPF
programs with TFO").

3. was moved to reqsk_queue_hash_req() in the previous patch.

Now, we always initialise req->timeout just before scheduling
the SYN+ACK timer:

  * For non-TFO SYN+ACK : reqsk_queue_hash_req()
  * For TFO SYN+ACK     : tcp_fastopen_create_child()

Let's remove the redundant initialisation of req->timeout in
reqsk_alloc() and inet_reqsk_alloc().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251106003357.273403-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07 18:05:25 -08:00
Kuniyuki Iwashima
3ce5dd8161 tcp: Remove timeout arg from reqsk_queue_hash_req().
inet_csk_reqsk_queue_hash_add() is no longer shared by DCCP.

We do not need to pass req->timeout down to reqsk_queue_hash_req().

Let's move tcp_timeout_init() from tcp_conn_request() to
reqsk_queue_hash_req().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251106003357.273403-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07 18:05:25 -08:00
Kuniyuki Iwashima
be88c549e9 tcp: Call tcp_syn_ack_timeout() directly.
Since DCCP has been removed, we do not need to use
request_sock_ops.syn_ack_timeout().

Let's call tcp_syn_ack_timeout() directly.

Now other function pointers of request_sock_ops are
protocol-dependent.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251106003357.273403-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-07 18:05:25 -08:00
Kees Cook
2b5e9f9b7e net: Convert struct sockaddr to fixed-size "sa_data[14]"
Revert struct sockaddr from flexible array to fixed 14-byte "sa_data",
to solve over 36,000 -Wflex-array-member-not-at-end warnings, since
struct sockaddr is embedded within many network structs.

With socket/proto sockaddr-based internal APIs switched to use struct
sockaddr_unsized, there should be no more uses of struct sockaddr that
depend on reading beyond the end of struct sockaddr::sa_data that might
trigger bounds checking.

Comparing an x86_64 "allyesconfig" vmlinux build before and after this
patch showed no new "ud1" instructions from CONFIG_UBSAN_BOUNDS nor any
new "field-spanning" memcpy CONFIG_FORTIFY_SOURCE instrumentations.

Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-8-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:33 -08:00
Kees Cook
8116d803e7 bpf: Convert cgroup sockaddr filters to use sockaddr_unsized consistently
Update BPF cgroup sockaddr filtering infrastructure to use sockaddr_unsized
consistently throughout the call chain, removing redundant explicit casts
from callers.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-6-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:33 -08:00
Kees Cook
449f68f8ff net: Convert proto callbacks from sockaddr to sockaddr_unsized
Convert struct proto pre_connect(), connect(), bind(), and bind_add()
callback function prototypes from struct sockaddr to struct sockaddr_unsized.
This does not change per-implementation use of sockaddr for passing around
an arbitrarily sized sockaddr struct. Those will be addressed in future
patches.

Additionally removes the no longer referenced struct sockaddr from
include/net/inet_common.h.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-5-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:33 -08:00