When a buffered read fails, iomap_finish_folio_read() reports the error
with fserror_report_io(folio->mapping->host, ...). This is called after
ifs->read_bytes_pending has been decremented by the bytes attempted to
be read.
For a folio split across multiple read completions, the folio is only
guaranteed to stay locked while read_bytes_pending > 0. Once
iomap_finish_folio_read() decrements read_bytes_pending, another
in-flight read can complete and end the read on the folio, which unlocks
it. This allows truncate logic to run and detach the folio (set
folio->mapping to NULL). The error reporting path then can dereference a
NULL folio->mapping. As reported by Sam Sun, this is the race that can
occur:
CPU0: failed completion CPU1: final completion CPU2: truncate
----------------------- ---------------------- --------------
read_bytes_pending -= len
finished = false
/* preempted before
fserror_report_io() */
read_bytes_pending -= len
finished = true
folio_end_read()
truncate clears
folio->mapping
fserror_report_io(
folio->mapping->host, ...)
^ NULL deref
Fix this by reporting the error first before decrementing
ifs->read_bytes_pending.
Fixes: a9d573ee88 ("iomap: report file I/O errors to the VFS")
Cc: stable@vger.kernel.org
Reported-by: Sam Sun <samsun1006219@gmail.com>
Closes: https://lore.kernel.org/linux-fsdevel/CAEkJfYPhWdd59RKmuNLJg-bkypHz7xiOwaWyNVu3A8CUqQCnvg@mail.gmail.com/
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://patch.msgid.link/20260604011858.2297561-1-joannelkoong@gmail.com
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
may_decode_fh() accesses mount::mnt_ns without holding any locks; that
means the mount can concurrently be unmounted, and the mnt_namespace can
concurrently be freed after an RCU grace period.
This race can happens as follows, assuming that the mount point was
created by open_tree(..., OPEN_TREE_CLONE):
thread 1 thread 2 RCU
__do_sys_open_by_handle_at
do_handle_open
handle_to_path
may_decode_fh
is_mounted
[mount::mnt_ns access]
[mount::mnt_ns access]
__do_sys_close
fput_close_sync
__fput
dissolve_on_fput
umount_tree
class_namespace_excl_destructor
namespace_unlock
free_mnt_ns
mnt_ns_tree_remove
call_rcu(mnt_ns_release_rcu)
mnt_ns_release_rcu
mnt_ns_release
kfree
[mnt_namespace::user_ns access] **UAF**
Fix it by taking rcu_read_lock() around the mount::mnt_ns access, like
in __prepend_path().
Additionally, document the semantics of mount::mnt_ns, and use WRITE_ONCE()
for writers that can race with lockless readers.
This bug is unreachable unless one of the following is set:
- CONFIG_PREEMPTION
- CONFIG_RCU_STRICT_GRACE_PERIOD
because it requires an RCU grace period to happen during a syscall without
an explicit preemption.
This doesn't seem to have interesting security impact; worst-case, it could
leak the result of an integer comparison to userspace (from the level
check in cap_capable()), cause an endless loop, or crash the kernel by
dereferencing an invalid address.
Fixes: 620c266f39 ("fhandle: relax open_by_handle_at() permission checks")
Cc: stable@vger.kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Link: https://patch.msgid.link/20260603-vfs-fhandle-uaf-fix-v2-1-d05db76a5084@google.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Lorenzo Bianconi says:
====================
Fix use-after-free in metadata dst teardown in airoha_eth and mtk_eth_soc drivers
airoha_metadata_dst_free() and mtk_free_dev() call metadata_dst_free()
which frees the metadata_dst with kfree() immediately, bypassing the RCU
grace period.
Replace metadata_dst_free() with dst_release() which properly goes
through the refcount path and runs call_rcu_hurry() if refcount goes to
zero.
====================
Link: https://patch.msgid.link/20260602-airoha-mtk-metadata-uaf-fix-v1-0-3aaa99d83351@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
mtk_free_dev() calls metadata_dst_free() which frees the metadata_dst
with kfree() immediately, bypassing the RCU grace period.
In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from
the skb to the metadata_dst. This function requires RCU read-side
protection and the dst must remain valid until all RCU readers complete.
Since metadata_dst_free() calls kfree() directly, a use-after-free can
occur if any skb still holds a noref pointer to the dst when the driver
tears it down.
Replace metadata_dst_free() with dst_release() which properly goes
through the refcount path: when the refcount drops to zero, it schedules
the actual free via call_rcu_hurry(), ensuring all RCU readers have
completed before the memory is freed.
Fixes: 2d7605a729 ("net: ethernet: mtk_eth_soc: enable hardware DSA untagging")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20260602-airoha-mtk-metadata-uaf-fix-v1-2-3aaa99d83351@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
airoha_metadata_dst_free() runs metadata_dst_free() which frees the
metadata_dst with kfree() immediately, bypassing the RCU grace period.
In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from
the skb to the metadata_dst. This function requires RCU read-side
protection and the dst must remain valid until all RCU readers complete.
Since metadata_dst_free() calls kfree() directly, an use-after-free can
occur if any skb still holds a noref pointer to the dst when the driver
tears it down.
Replace metadata_dst_free() with dst_release() which properly goes
through the refcount path: when the refcount drops to zero, it schedules
the actual free via call_rcu_hurry(), ensuring all RCU readers have
completed before the memory is freed.
Fixes: af3cf757d5 ("net: airoha: Move DSA tag in DMA descriptor")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20260602-airoha-mtk-metadata-uaf-fix-v1-1-3aaa99d83351@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Luiz Augusto von Dentz says:
====================
bluetooth pull request for net:
- hci_core: fix memory leak in error path of hci_alloc_dev()
- hci_sync: reject oversized Broadcast Announcement prepend
- MGMT: Fix backward compatibility with userspace
- MGMT: validate advertising TLV before type checks
- L2CAP: reject BR/EDR signaling packets over MTUsig
- RFCOMM: validate skb length in MCC handlers
- RFCOMM: hold listener socket in rfcomm_connect_ind()
- ISO: Fix not releasing hdev reference on iso_conn_big_sync
- ISO: Fix a use-after-free of the hci_conn pointer
- ISO: Fix data-race on iso_pi fields in hci_get_route calls
- SCO: Fix data-race on sco_pi fields in sco_connect
- BNEP: reject short frames before parsing
* tag 'for-net-2026-06-03' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth:
Bluetooth: MGMT: Fix backward compatibility with userspace
Bluetooth: SCO: Fix data-race on sco_pi fields in sco_connect
Bluetooth: ISO: Fix data-race on iso_pi fields in hci_get_route calls
Bluetooth: ISO: Fix a use-after-free of the hci_conn pointer
Bluetooth: ISO: Fix not releasing hdev reference on iso_conn_big_sync
Bluetooth: fix memory leak in error path of hci_alloc_dev()
Bluetooth: bnep: reject short frames before parsing
Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend
Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig
Bluetooth: RFCOMM: validate skb length in MCC handlers
Bluetooth: MGMT: validate advertising TLV before type checks
Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()
====================
Link: https://patch.msgid.link/20260603162714.342496-1-luiz.dentz@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Johannes Berg says:
====================
Things are finally quieting down:
- iwlwifi:
- FW reset handshake removal for older devices
- NIC access fix in fast resume
- avoid too large command for some BIOSes
- fix TX power constraints in AP mode
- cfg80211:
- fix netlink parse overflow
- fix potential 6 GHz scan memory leak
- enforce HE/EHT consistency to avoid mac80211 crash
- mac80211: guard radiotap antenna parsing
* tag 'wireless-2026-06-03' of https://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless:
wifi: cfg80211: enforce HE/EHT cap/oper consistency
wifi: fix leak if split 6 GHz scanning fails
wifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap
wifi: nl80211: reject oversized EMA RNR lists
wifi: iwlwifi: pcie: simplify the resume flow if fast resume is not used
wifi: iwlwifi: mvm: avoid oversized UATS command copy
wifi: iwlwifi: mld: send tx power constraints before link activation
wifi: iwlwifi: mvm: don't support the reset handshake for old firmwares
====================
Link: https://patch.msgid.link/20260603113208.171874-3-johannes@sipsolutions.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Matthieu Baerts says:
====================
mptcp: misc fixes for v7.1-rc7
Here are various unrelated fixes:
- Patch 1: fix missing wakeups when multiple threads are reading from
the same fd. A fix for v5.7.
- Patch 2: fix retransmission loop when MPTCP checksum is enabled. A fix
for v5.14.
- Patch 3: fix a TOCTOU race while computing rcv_wnd. A fix for v5.11.
- Patch 4: allow subflows receive window to shrink if needed. A fix for
v5.19.
- Patches 5-6: avoid 'extra_subflows' to underflow with the userspace
PM. A fix for v5.19.
- Patch 7: report errors if one subflow cannot set SO_TIMESTAMPING. A
fix for v5.14.
- Patch 8: try to set TCP_MAXSEG on all subflows, before reporting
errors, if any. A fix for v6.17.
- Patch 9: check desc->count in read_sock, to act as expected. A fix
for v7.0.
- Patch 10: fix an uninit value in mptcp_established_options, reported
by syzbot. A fix for v7.1-rc1.
- Patch 11: fix a similar issue than the previous patch, exposed by the
same modification from v7.1-rc1, but was already causing issues since
v5.15.
====================
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-0-856831229976@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When an ADD_ADDR needs to be sent, it could be prepared if there is
enough remaining space and even if the packet is not a pure ACK. But it
would be dropped soon after.
Indeed, in mptcp_pm_add_addr_signal(), there is enough space to fit a
DSS of 20 octets and an ADD_ADDR echo containing an IPv4 address on 8
octets for example. In this case, the packet would be prepared, the
MPTCP_ADD_ADDR_ECHO bit would be removed from pm->addr_signal, but the
option would be silently dropped in mptcp_established_options_add_addr()
not to override DSS info in the union from 'struct mptcp_out_options',
and also because mptcp_write_options() will enforce mutually exclusion
with DSS.
Instead, don't even try to send an ADD_ADDR if it is not a pure ACK.
Retry for each new packet until a pure-ACK is emitted. That's fine to do
that, because each time an ADD_ADDR (echo) is scheduled, a pure ACK is
queued.
This also simplifies the code, and the skb checks can be done earlier,
before the lock.
Note: also, since commit 6d0060f600 ("mptcp: Write MPTCP DSS headers
to outgoing data packets"), opts->ahmac would not have been set to 0
when other suboptions were not dropped, and when sending an ADD_ADDR
echo. That would have resulted in sending an ADD_ADDR using garbage
info, where there was not enough space, instead of an echo one without
the ADD_ADDR HMAC.
Fixes: 1bff1e43a3 ("mptcp: optimize out option generation")
Cc: stable@vger.kernel.org
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-11-856831229976@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The userspace PM increments extra_subflows after __mptcp_subflow_connect()
succeeds, but __mptcp_subflow_connect() calls mptcp_pm_close_subflow()
on failure to roll back the pre-increment done by the kernel PM's fill_*()
helpers. Because the userspace PM hasn't incremented yet at that point,
this decrement is spurious and causes extra_subflows to underflow.
Fix it by aligning the userspace PM with the kernel PM: increment
extra_subflows before calling __mptcp_subflow_connect(), so the existing
error path in subflow.c correctly rolls it back on failure. Also simplify
the error handling by taking pm.lock only when needed for cleanup.
Fixes: 77e4b94a3d ("mptcp: update userspace pm infos")
Cc: stable@vger.kernel.org
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-5-856831229976@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In MPTCP connection, the `window` field in the TCP header refers to the
MPTCP-level rcv_nxt and it's right edge should not move backward. Such
constraint is enforced at DSS option generation time.
At the same time, the TCP stack ensures independently that the TCP-level
rcv wnd right's edge does not move backward. That in turn causes artificial
inflating of the MPTCP rcv window when the incoming data is acked at the
TCP level and is OoO in the MPTCP sequence space (or lands in the backlog).
As a consequence, the incoming traffic can exceed the receiver rcvbuf size
even when the sender is not misbehaving.
Prevent such scenario forcibly allowing the TCP subflow to shrink the
TCP-level rcv wnd regardless of the current netns setting.
Fixes: f3589be0c4 ("mptcp: never shrink offered window")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-4-856831229976@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The MPTCP output path access locklessly the MPTCP-level ack_seq
in multiple times, using possibly different values for the data_ack
in the DSS option and to compute the announced rcv wnd for the same
packet.
Refactor the cote to avoid inconsistencies which may confuse the
peer. Also ensure that the MPTCP level rcv wnd is updated only when
the egress packet actually contains a DSS ack.
Fixes: fa3fe2b150 ("mptcp: track window announced to peer")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-3-856831229976@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch restricts setting Loose Source and Record Route (LSRR)
and Strict Source and Record Route (SSRR) IP options to users
with CAP_NET_RAW capability.
This prevents unprivileged applications from forcing packets to route
through attacker-controlled nodes to leak TCP ISN and possibly other
protocol information.
While LSRR and SSRR are commonly filtered in many network environments,
they may still be supported and forwarded along some network paths.
RFC 7126 (Recommendations on Filtering of IPv4 Packets Containing
IPv4 Options) recommend to drop these options in 4.3 and 4.4.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Tamir Shahar <tamirthesis@gmail.com>
Reported-by: Amit Klein <aksecurity@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260602161547.2642155-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add test to verify that when a skb is partially consumed,
unix_inq_len() return correct remaining byte count.
Before:
# RUN scm_inq.stream.partial_read ...
# scm_inq.c:165:partial_read:Expected remain (512) == *(int *)CMSG_DATA(cmsg) (768)
# partial_read: Test terminated by assertion
# FAIL scm_inq.stream.partial_read
not ok 2 scm_inq.stream.partial_read
After:
# RUN scm_inq.stream.partial_read ...
# OK scm_inq.stream.partial_read
ok 2 scm_inq.stream.partial_read
Signed-off-by: Jianyu Li <jianyu.li@mediatek.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260601113640.231897-3-jianyu.li@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently inq_len is updated only when the whole skb is consumed.
If only part of the data is read, following SIOCINQ query would
get value greater than what actually left.
This change update inq_len timely in unix_stream_read_generic(),
and adjust unix_stream_read_skb() accordingly to prevent
repetitive update.
Fixes: f4e1fb04c1 ("af_unix: Use cached value for SOCK_STREAM in unix_inq_len().")
Signed-off-by: Jianyu Li <jianyu.li@mediatek.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260601113640.231897-2-jianyu.li@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
NPC mcam entry stores a mapping between mcam entry and target pcifunc.
During initialization of this field, API kmalloc_array has been used which
caused some junk values to array. Whereas, the array is expected to be
initialized by 0. This patch fixes the same by using kcalloc instead of
kmalloc_array.
Fixes: 55307fcb92 ("octeontx2-af: Add mbox messages to install and delete MCAM rules")
Signed-off-by: Suman Ghosh <sumang@marvell.com>
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/1780054625-17090-1-git-send-email-sbhatta@marvell.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sfp->i2c_block_size is only assigned in sfp_sm_mod_probe(), which runs
from the state machine timer after SFP_F_PRESENT has been set. Between
those two points, sfp_module_eeprom() (the ethtool -m callback) gates
only on SFP_F_PRESENT and can be entered with i2c_block_size still at
its kzalloc'd value of 0.
On a pure-I2C adapter, sfp_i2c_read() then issues an i2c_transfer()
with msgs[1].len = 0 inside a loop that subtracts this_len from len
each iteration; on adapters that succeed a zero-length read the loop
never advances, spinning while holding rtnl_lock.
This was previously addressed by initializing i2c_block_size in
sfp_alloc() (commit 813c2dd786), but the initialization was dropped
when i2c_block_size was split from i2c_max_block_size.
Initialize sfp->i2c_block_size from sfp->i2c_max_block_size in
sfp_i2c_configure(), so the field is valid as soon as the adapter is
known. sfp_sm_mod_probe() still reassigns it on each module insertion
to recover from a per-module clamp to 1 (sfp_id_needs_byte_io).
Fixes: 7662abf4db ("net: phy: sfp: Add support for SMBus module access")
Cc: stable@vger.kernel.org
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Link: https://patch.msgid.link/20260528205242.971410-2-jelonek.jonas@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The TX metadata area resides in the UMEM buffer which is memory-mapped
and concurrently writable by userspace. In xsk_skb_metadata(),
csum_start and csum_offset are read from shared memory for bounds
validation, then read again for skb assignment. A malicious userspace
application can race to overwrite these values between the two reads,
bypassing the bounds check and causing out-of-bounds memory access
during checksum computation in the transmit path.
Fix this by reading csum_start and csum_offset into local variables
once, then using the local copies for both validation and assignment.
Note that other metadata fields (flags, launch_time) and the cached
csum fields may be mutually inconsistent due to concurrent userspace
writes, but this is benign: the only security-critical invariant is
that each field's validated value is the same one used, which local
caching guarantees.
Closes: https://lore.kernel.org/all/20260503200927.73EA1C2BCB4@smtp.kernel.org/
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Fixes: 48eb03dd26 ("xsk: Add TX timestamp and TX checksum offload support")
Link: https://patch.msgid.link/20260530042630.80626-1-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since 5e8eb9aeed ("arm64: mm: always call PTE/PMD ctor in
__create_pgd_mapping()") page-table allocation on ARM64 always calls
pagetable_{pte,pmd,pud,p4d}_ctor(). This sets the page_type to
PGTY_table, increments NR_PAGETABLE and possible allocates a PTL. However
the matching pagetable_dtor() calls were never added.
With DEBUG_VM enabled on kernel versions prior to v6.17 without
2dfcd1608f ("mm/page_alloc: let page freeing clear any set page type")
this leads to the following warning when freeing these pages due to
page->page_type sharing page->_mapcount:
BUG: Bad page state in process ... pfn:284fbb
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x284fbb
flags: 0x17fffc000000000(node=0|zone=2|lastcpupid=0x1ffff)
page_type: f2(table)
page dumped because: nonzero mapcount
Call trace:
bad_page+0x13c/0x160
__free_frozen_pages+0x6cc/0x860
___free_pages+0xf4/0x180
free_pages+0x54/0x80
free_hotplug_page_range.part.0+0x58/0x90
free_empty_tables+0x438/0x500
__remove_pgd_mapping.constprop.0+0x60/0xa8
arch_remove_memory+0x48/0x80
try_remove_memory+0x158/0x1d8
offline_and_remove_memory+0x138/0x180
It can also lead to leaking the ptl allocation if ALLOC_SPLIT_PTLOCKS is
defined and incorrect NR_PAGETABLE stats. Fix this by calling
pagetable_dtor() in free_hotplug_pgtable_page() prior to freeing the page
to undo the effects of calling pagetable_*_ctor().
Link: https://lore.kernel.org/20260521032730.2104017-1-apopple@nvidia.com
Fixes: 5e8eb9aeed ("arm64: mm: always call PTE/PMD ctor in __create_pgd_mapping()")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
memcg_reparent_list_lrus() clears the dying memcg's xarray entry with
xas_store(&xas, NULL) before reparenting its per-node lists into the
parent. This opens a window where a concurrent list_lru_del() arriving
for the dying memcg sees xa_load() == NULL, walks to the parent in
lock_list_lru_of_memcg(), takes the parent's per-node lock, and calls
list_del_init() on an item still physically linked on the dying memcg's
list.
If another in-flight thread holds the dying memcg's per-node lock at the
same moment (another list_lru_del, or a list_lru_walk_one running an
isolate callback), both threads modify ->next/->prev pointers on the same
physical list under different locks. Adjacent items can corrupt each
other's links.
Fix it by reversing the order: reparent each per-node list and mark the
child's list lru dead and then clear the xarray entry. Any concurrent
list_lru op that finds the still-set xarray entry either takes the dying
memcg's per-node lock (synchronizing with the drain) or sees LONG_MIN and
walks to the parent, where the items now live.
Link: https://lore.kernel.org/20260601161501.1444829-1-shakeel.butt@linux.dev
Fixes: fb56fdf8b9 ("mm/list_lru: split the lock to per-cgroup scope")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reported-by: Chris Mason <clm@fb.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 65edfda6f3 ("mm/rmap: extend rmap and migration support
device-private entries") updated set_pmd_migration_entry() to use
pmdp_huge_get_and_clear() in the softleaf case, but made no further
adjustments to the function itself.
Therefore this function continues to incorrectly use pmd_write(),
pmd_soft_dirty() and pmd_uffd_wp() to determine whether the installed
migration entry should be marked writable, softdirty or uffd-wp
respectively.
Whilst all are incorrect, the most problematic of these is pmd_write(), as
this can lead to corrupted rmap state.
On x86-64 _PAGE_SWP_SOFT_DIRTY is aliased to _PAGE_RW. So calling
pmd_write() on a softleaf will return the softdirty state encoded in the
entry, assuming CONFIG_MEM_SOFT_DIRTY was enabled.
This was observed when running the hmm.hmm_device_private.anon_write_child
selftest:
1. The test faults in a range then migrates it such that a device-private
THP range is established.
2. The parent then migrates it to a device-private writable PMD entry whose
folio is entirely AnonExclusive with entire_mapcount=1, softdirty set
(accidentally correct write state).
3. The parent forks and the PMD entries are set to device-private read only
entries, entire_mapcount=2, softdirty still set.
4. [BUG] The child writes to the range then migrates to RAM - intending to
install non-writable migration entries - but replacing parent and child
PMD mappings with WRITABLE entries due to misinterpreting the softdirty
bit.
5. In remove_migration_pmd(), if !softleaf_is_migration_read(entry) we
set the RMAP_EXCLUSIVE flag when calling folio_add_anon_rmap_pmd() for
both parent and child, which are therefore AnonExclusive.
6. [SPLAT] Child sets migrated folio entire_mapcount=1, parent sets
entire_mapcount=2 and we end up with an AnonExclusive folio with
entire_mapcount=2! Assert fires in __folio_add_anon_rmap():
VM_WARN_ON_FOLIO(folio_test_large(folio) &&
folio_entire_mapcount(folio) > 1 &&
PageAnonExclusive(cur_page), folio)
This patch fixes the issue by correctly referencing the softleaf entry
fields for writable, softdirty and uffd-wp in set_pmd_migration_entry().
It also only updates A/D flags if the entry is present as these are
otherwise not meaningful for a softleaf entry.
This patch also flips the if (!present) { ... } else { ... } logic in
set_pmd_migration_entry() so it is easier to understand, and adds some
comments to make things clearer.
I was able to bisect this to commit 775465fd26 ("lib/test_hmm: add zone
device private THP test infrastructure") which first exposes this bug as
it was the commit that permitted test_hmm to generate the test.
However commit 65edfda6f3 ("mm/rmap: extend rmap and migration support
device-private entries") is the commit that actually enabled this
behaviour.
Link: https://lore.kernel.org/20260601083044.57132-1-ljs@kernel.org
Fixes: 65edfda6f3 ("mm/rmap: extend rmap and migration support device-private entries")
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Balbir Singh <balbirs@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Oscar Salvador (SUSE) <osalvador@kernel.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON_LRU_SORT allocates the damon_ctx object for its kdamond in its init
function. damon_lru_sort_enabled_store() wrongly assumes the allocation
will always succeed once tried. If the damon_ctx allocation was failed,
therefore, code execution reaches to damon_commit_ctx() while 'ctx' is
NULL. As a result, it dereferences the NULL 'ctx' pointer. Avoid the
NULL dereference by returning -ENOMEM if 'ctx' is NULL.
Link: https://lore.kernel.org/20260529000104.7006-3-sj@kernel.org
Fixes: c4a8e662c8 ("mm/damon/lru_sort: use damon_initialized()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon/{reclaim,lru_sort}: handle ctx allocation failures".
DAMON_RECLAIM and DAMON_LRU_SORT could dereference NULL pointers if their
damon_ctx object allocations fail. The bugs are expected to happen
infrequently because the allocations are arguably too small to fail on
common setups. But theoretically they are possible and the consequences
are bad. Fix those.
The issues were discovered [1] by Sashiko.
This patch (of 2):
DAMON_RECLAIM allocates the damon_ctx object for its kdamond in its init
function. damon_reclaim_enabled_store() wrongly assumes the allocation
will always succeed once tried. If the damon_ctx allocation was failed,
therefore, code execution reaches to damon_commit_ctx() while 'ctx' is
NULL. As a result, it dereferences the NULL 'ctx' pointer. Avoid the
NULL dereference by returning -ENOMEM if 'ctx' is NULL.
Link: https://lore.kernel.org/20260529000104.7006-2-sj@kernel.org
Link: https://lore.kernel.org/20260419014800.877-1-sj@kernel.org [1]
Fixes: 3f7a914ab9 ("mm/damon/reclaim: use damon_initialized()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
zram_read_page() picks the sync or async backing device read path based on
whether the parent bio is NULL. zram_bvec_write_partial() passes its
parent bio down, so for ZRAM_WB slots the read is dispatched
asynchronously and zram_read_page() returns 0 while the bio is still in
flight. The caller then runs memcpy_from_bvec(), zram_write_page() and
__free_page() on the buffer, leaving the async read to write into a freed
page.
zram_bvec_read_partial() was switched to NULL in commit 4e3c87b942
("zram: fix synchronous reads") for the same reason; the write_partial
counterpart was missed.
Link: https://lore.kernel.org/20260528-zram-v3-1-cab86eef8764@gmail.com
Fixes: 8e654f8fbf ("zram: read page from backing device")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Cunlong Li <shenxiaogll@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After commit 9b93f7e327 ("tools/getdelays: use the static UAPI headers
from tools/include/uapi"), the Makefile was changed to use
-I../include/uapi/ instead of -I../../usr/include to ensure tools always
use the up-to-date UAPI headers.
However, only linux/taskstats.h was added to tools/include/uapi/ in commit
e5bbb35a07 ("tools headers UAPI: sync linux/taskstats.h"), but
linux/acct.h was missing.
This causes procacct.c to fail to compile with:
procacct.c:234:37: error: 'AGROUP' undeclared (first use in this function)
gcc -I../include/uapi/ getdelays.c -o getdelays
gcc -I../include/uapi/ procacct.c -o procacct
procacct.c: In function `print_procacct':
procacct.c:234:37: error: `AGROUP' undeclared (first use in this function)
did you mean `NOGROUP'?
234 | , t->version >= 12 ? (t->ac_flag & AGROUP ? 'P' : 'T') : '?'
| ^~~~~~
| NOGROUP
procacct.c:234:37: note: each undeclared ident
because procacct.c uses the AGROUP macro defined in linux/acct.h.
Add the missing linux/acct.h to complete the static UAPI header set.
Link: https://lore.kernel.org/20260527213558929EhiHHy9EDTMjmg3uuDOMi@zte.com.cn
Fixes: 9b93f7e327 ("tools/getdelays: use the static UAPI headers from tools/include/uapi")
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
syzbot triggered the following splat in remove_waiter() via
FUTEX_CMP_REQUEUE_PI:
KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f]
class_raw_spinlock_constructor
remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561
rt_mutex_start_proxy_lock+0x103/0x120
futex_requeue+0x10e4/0x20d0
__x64_sys_futex+0x34f/0x4d0
task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection,
leaving waiter->task nil, where 3bfdc63936 ("rtmutex: Use waiter::task instead
of current in remove_waiter()") made this fatal.
Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter()
upon a successfully grabbing the rtmutex. 1a1fb985f2 ("futex: Handle early deadlock
return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock()
(where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to
account for try_to_take_rt_mutex().
Fixes: 3bfdc63936 ("rtmutex: Use waiter::task instead of current in remove_waiter()")
Reported-by: syzbot+78147abe6c524f183ee9@syzkaller.appspotmail.com
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/all/69f114ac.050a0220.ac8b.0003.GAE@google.com/
Link: https://patch.msgid.link/20260507112913.1019537-1-dave@stgolabs.net
kvm_walk_nested_s2() returns -EAGAIN as an indication that an underlying
descriptor update fails due to a race. The expectation is that the
caller restart translation, yet walk_s1() actually synthesizes an abort.
Propagate the -EAGAIN return out of walk_s1(), relying on callers to
restart the translation fetch.
Fixes: e4c7dfac2f ("KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW")
Signed-off-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260602235450.103057-6-oupton@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
__kvm_at_s*() are expected to return -EAGAIN if the page table walk
raced with a concurrent update to a page table descriptor, which is
interpreted as a signal to restart the trapping instruction.
While this mostly works, __kvm_at_s12() silently eats the return from
__kvm_at_s1e01() and consumes an uninitialized PAR value. Propagate the
nonzero return instead.
Fixes: 92c6443222 ("KVM: arm64: Propagate PTW errors up to AT emulation")
Signed-off-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260602235450.103057-5-oupton@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Similar to the handling of descriptor reads, inject an SEA during TTW
when the descriptor access fails for reasons other than a race, such as
a read-only memslot or a bad HVA.
Fixes: bff8aa213d ("KVM: arm64: Implement HW access flag management in stage-1 SW PTW")
Fixes: e4c7dfac2f ("KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW")
Signed-off-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260602235450.103057-4-oupton@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
kvm_translate_vncr() first invalidates the pseudo-TLB entry and
corresponding fixmap in anticipation of installing a new translation.
While the fixmap invalidation does clear the mapping from host stage-1,
it does not clear the L1_VNCR_MAPPED flag. Depending on the state of the
VNCR TLB at vcpu_put(), this could potentially precipitate a BUG_ON() if
vt->cpu is reset.
Share a helper with kvm_vcpu_put_hw_mmu(), ensuring that KVM's view of
the VNCR fixmap is in sync with the state of the VNCR TLB. Give it a
slightly verbose name to make it obvious that it is meant to be used
local to a CPU, unlike other VNCR TLB maintenance.
Fixes: 069a05e535 ("KVM: arm64: nv: Handle VNCR_EL2-triggered faults")
Signed-off-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260602235450.103057-3-oupton@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
KVM needs to know if the HW implements FEAT_ATS1A in order to correctly
sanitise HFGITR_EL2.ATS1E1A, which otherwise defaults to RES0 and
AT S1E1A traps are handled as UNDEF.
Solves this by exposing ID_AA64ISAR2_EL1.ATS1A to the rest of the kernel.
Fixes: ff987ffc0c ("KVM: arm64: nv: Add support for FEAT_ATS1A")
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260602155430.2088142-4-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Despite having handling code for AT S1E1A, the instruction was
never plugged into the system instruction table, leading to an
exception being injected in the guest.
If the guest is Linux and using the __kvm_at() helper, the exception
is actually handled in the helper, and KVM continues more or less
silently by reentering the guest. Not exactly what you'd expect.
Fix this by plugging the emulation code where required.
Fixes: ff987ffc0c ("KVM: arm64: nv: Add support for FEAT_ATS1A")
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260602155430.2088142-3-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
We propagate CPTR_EL2.E0POE from a L1 into the L0 configuration, but
we key this on the L1 guest supporting FEAT_S2POE. This is obviously
wrong, as this bit is solely concerned with Stage-1 translation.
Fix this by making the update depend on FEAT_S1POE.
Fixes: cd931bd609 ("KVM: arm64: nv: Add additional trap setup for CPTR_EL2")
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Link: https://patch.msgid.link/20260602155430.2088142-2-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
