Pull MM fixes from Andrew Morton:
"28 hotfixes.
23 are cc:stable and the other five address issues which were
introduced during this merge cycle.
20 are for MM and the remainder are for other subsystems"
* tag 'mm-hotfixes-stable-2023-04-07-16-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (28 commits)
maple_tree: fix a potential concurrency bug in RCU mode
maple_tree: fix get wrong data_end in mtree_lookup_walk()
mm/swap: fix swap_info_struct race between swapoff and get_swap_pages()
nilfs2: fix sysfs interface lifetime
mm: take a page reference when removing device exclusive entries
mm: vmalloc: avoid warn_alloc noise caused by fatal signal
nilfs2: initialize "struct nilfs_binfo_dat"->bi_pad field
nilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()
zsmalloc: document freeable stats
zsmalloc: document new fullness grouping
fsdax: force clear dirty mark if CoW
mm/hugetlb: fix uffd wr-protection for CoW optimization path
mm: enable maple tree RCU mode by default
maple_tree: add RCU lock checking to rcu callback functions
maple_tree: add smp_rmb() to dead node detection
maple_tree: fix write memory barrier of nodes once dead for RCU mode
maple_tree: remove extra smp_wmb() from mas_dead_leaves()
maple_tree: fix freeing of nodes in rcu mode
maple_tree: detect dead nodes in mas_start()
maple_tree: be more cautious about dead nodes
...
Daniel Borkmann says:
====================
pull-request: bpf 2023-04-08
We've added 4 non-merge commits during the last 11 day(s) which contain
a total of 5 files changed, 39 insertions(+), 6 deletions(-).
The main changes are:
1) Fix BPF TCP socket iterator to use correct helper for dropping
socket's refcount, that is, sock_gen_put instead of sock_put,
from Martin KaFai Lau.
2) Fix a BTI exception splat in BPF trampoline-generated code on arm64,
from Xu Kuohai.
3) Fix a LongArch JIT error from missing BPF_NOSPEC no-op, from George Guo.
4) Fix dynamic XDP feature detection of veth in xdp_redirect selftest,
from Lorenzo Bianconi.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: fix xdp_redirect xdp-features selftest for veth driver
bpf, arm64: Fixed a BTI error on returning to patched function
LoongArch, bpf: Fix jit to skip speculation barrier opcode
bpf: tcp: Use sock_gen_put instead of sock_put in bpf_iter_tcp
====================
Link: https://lore.kernel.org/r/20230407224642.30906-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The following example forces veristat to loop indefinitely:
$ cat two-ok
file_name,prog_name,verdict,total_states
file-a,a,success,12
file-b,b,success,67
$ cat add-failure
file_name,prog_name,verdict,total_states
file-a,a,success,12
file-b,b,success,67
file-b,c,failure,32
$ veristat -C two-ok add-failure
<does not return>
The loop is caused by handle_comparison_mode() not checking if `base`
variable points to `fallback_stats` prior advancing joined results
using `base`.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230407154125.896927-1-eddyz87@gmail.com
perf_event with type=PERF_TYPE_RAW and config=0x1b00 turned out to be not
reliable in ensuring LBR is active. Thus, test_progs:get_branch_snapshot is
not reliable in some systems. Replace it with PERF_COUNT_HW_CPU_CYCLES
event, which gives more consistent results.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230407190130.2093736-1-song@kernel.org
This patch add bonding arp validate tests with mode active backup,
monitor arp_ip_target and ns_ip6_target. It also checks mii_status
to make sure all slaves are UP.
Acked-by: Jonathan Toppins <jtoppins@redhat.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To improve the testing process for bond options, A new bond topology lib
is added to our testing setup. The current option_prio.sh file will be
renamed to bond_options.sh so that all bonding options can be tested here.
Specifically, for priority testing, we will run all tests using modes
1, 5, and 6. These changes will help us streamline the testing process
and ensure that our bond options are rigorously evaluated.
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Jonathan Toppins <jtoppins@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Running this test makes little sense if the enabled l3_stats are not
actually reported as "used". This can signify a failure of a driver to
install the necessary counters, or simply lack of support for enabling
in-HW counters on a given netdevice. It is generally impossible to tell
from the outside which it is. But more likely than not, if somebody is
running this on veth pairs, they do not intend to actually test that a
certain piece of HW can install in-HW counters for the veth. It is more
likely they are e.g. running the test by mistake.
Therefore detect that the counter has not been actually installed. In that
case, if the netdevice is one end of a veth pair, SKIP. Otherwise FAIL.
Suggested-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Tested-by: Hangbin Liu <liuhangbin@gmail.com>
Link: https://lore.kernel.org/r/a86817961903cca5cb0aebf2b2a06294b8aa7dea.1680704172.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add various tests for code pattern '<const> <cond_op> <non_const>' to
exercise the previous verifier patch.
The following are veristat changed number of processed insns stat
comparing the previous patch vs. this patch:
File Program Insns (A) Insns (B) Insns (DIFF)
----------------------------------------------------- ---------------------------------------------------- --------- --------- -------------
test_seg6_loop.bpf.linked3.o __add_egr_x 12423 12314 -109 (-0.88%)
Only one program is affected with minor change.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230406164510.1047757-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, the verifier does not handle '<const> <cond_op> <non_const>' well.
For example,
...
10: (79) r1 = *(u64 *)(r10 -16) ; R1_w=scalar() R10=fp0
11: (b7) r2 = 0 ; R2_w=0
12: (2d) if r2 > r1 goto pc+2
13: (b7) r0 = 0
14: (95) exit
15: (65) if r1 s> 0x1 goto pc+3
16: (0f) r0 += r1
...
At insn 12, verifier decides both true and false branch are possible, but
actually only false branch is possible.
Currently, the verifier already supports patterns '<non_const> <cond_op> <const>.
Add support for patterns '<const> <cond_op> <non_const>' in a similar way.
Also fix selftest 'verifier_bounds_mix_sign_unsign/bounds checks mixing signed and unsigned, variant 10'
due to this change.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230406164505.1046801-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull networking fixes from Jakub Kicinski:
"Including fixes from wireless and can.
Current release - regressions:
- wifi: mac80211:
- fix potential null pointer dereference
- fix receiving mesh packets in forwarding=0 networks
- fix mesh forwarding
Current release - new code bugs:
- virtio/vsock: fix leaks due to missing skb owner
Previous releases - regressions:
- raw: fix NULL deref in raw_get_next().
- sctp: check send stream number after wait_for_sndbuf
- qrtr:
- fix a refcount bug in qrtr_recvmsg()
- do not do DEL_SERVER broadcast after DEL_CLIENT
- wifi: brcmfmac: fix SDIO suspend/resume regression
- wifi: mt76: fix use-after-free in fw features query.
- can: fix race between isotp_sendsmg() and isotp_release()
- eth: mtk_eth_soc: fix remaining throughput regression
- eth: ice: reset FDIR counter in FDIR init stage
Previous releases - always broken:
- core: don't let netpoll invoke NAPI if in xmit context
- icmp: guard against too small mtu
- ipv6: fix an uninit variable access bug in __ip6_make_skb()
- wifi: mac80211: fix the size calculation of
ieee80211_ie_len_eht_cap()
- can: fix poll() to not report false EPOLLOUT events
- eth: gve: secure enough bytes in the first TX desc for all TCP
pkts"
* tag 'net-6.3-rc6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (47 commits)
net: stmmac: check fwnode for phy device before scanning for phy
net: stmmac: Add queue reset into stmmac_xdp_open() function
selftests: net: rps_default_mask.sh: delete veth link specifically
net: fec: make use of MDIO C45 quirk
can: isotp: fix race between isotp_sendsmg() and isotp_release()
can: isotp: isotp_ops: fix poll() to not report false EPOLLOUT events
can: isotp: isotp_recvmsg(): use sock_recv_cmsgs() to get SOCK_RXQ_OVFL infos
can: j1939: j1939_tp_tx_dat_new(): fix out-of-bounds memory access
gve: Secure enough bytes in the first TX desc for all TCP pkts
netlink: annotate lockless accesses to nlk->max_recvmsg_len
ethtool: reset #lanes when lanes is omitted
ping: Fix potentail NULL deref for /proc/net/icmp.
raw: Fix NULL deref in raw_get_next().
ice: Reset FDIR counter in FDIR init stage
ice: fix wrong fallback logic for FDIR
net: stmmac: fix up RX flow hash indirection table when setting channels
net: ethernet: ti: am65-cpsw: Fix mdio cleanup in probe
wifi: mt76: ignore key disable commands
wifi: ath11k: reduce the MHI timeout to 20s
ipv6: Fix an uninit variable access bug in __ip6_make_skb()
...
Pull Kselftest fixes from Shuah Khan:
"One single fix to mount_setattr_test build failure"
* tag 'linux-kselftest-fixes-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests mount: Fix mount_setattr_test builds failed
ACPICA commit 44f1af0664599e87bebc3a1260692baa27b2f264
Similar to "Replace one-element array with flexible-array", replace the
1-element array with a proper flexible array member as defined by C99.
This allows the code to operate without tripping compile-time and run-
time bounds checkers (e.g. via __builtin_object_size(), -fsanitize=bounds,
and/or -fstrict-flex-arrays=3).
The sizeof() uses with struct acpi_nfit_flush_address and struct
acpi_nfit_smbios have been adjusted to drop the open-coded subtraction
of the trailing single element. The result is no binary differences in
.text nor .data sections.
Link: https://github.com/acpica/acpica/commit/44f1af06
Signed-off-by: Bob Moore <robert.moore@intel.com>
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add unaligned descriptor test for frame size of 4001. Using an odd frame
size ensures that the end of the UMEM is not near a page boundary. This
allows testing descriptors that staddle the end of the UMEM but not a
page.
This test used to fail without the previous commit ("xsk: Fix unaligned
descriptor validation").
Signed-off-by: Kal Conley <kal.conley@dectris.com>
Link: https://lore.kernel.org/r/20230405235920.7305-3-kal.conley@dectris.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Commit 515bddf0ec ("selftests/clone3: test clone3 with CLONE_NEWTIME")
added an additional test, so the number passed to ksft_set_plan needs to
be bumped accordingly.
Also use ksft_finished() to print results and exit. This will catch future
mismatches between ksft_set_plan() and the number of tests being run.
Fixes: 515bddf0ec ("selftests/clone3: test clone3 with CLONE_NEWTIME")
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Although there is a provision for 52 bit VA on arm64 platform, it remains
unutilised and higher addresses are not allocated. In order to
accommodate 4PB [2^52] virtual address space where supported,
NR_CHUNKS_HIGH is changed accordingly.
Array holding addresses is changed from static allocation to dynamic
allocation to accommodate its voluminous nature which otherwise might
overflow the stack.
Link: https://lkml.kernel.org/r/20230323060121.1175830-3-chaitanyas.prakash@arm.com
Signed-off-by: Chaitanya S Prakash <chaitanyas.prakash@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "selftests: Fix virtual address range for arm64", v2.
When the virtual address range selftest is run on arm64 and x86 platforms,
it is observed that both the low and high VA range iterations are skipped
when the MAP_CHUNK_SIZE is set to 16GB. The MAP_CHUNK_SIZE is changed to
1GB to resolve this issue, following which support for arm64 platform is
added by changing the NR_CHUNKS_HIGH for aarch64 to accommodate up to 4PB
of virtual address space allocation requests. Dynamic memory allocation
of array holding addresses is introduced to prevent overflow of the stack.
Finally, the overcommit_policy is set as OVERCOMMIT_ALWAYS to prevent the
kernel from denying a memory allocation request based on a platform's
physical memory availability.
This patch (of 3):
mmap() fails to allocate 16GB virtual space chunk, skipping both low and
high VA range iterations. Hence, reduce MAP_CHUNK_SIZE to 1GB and update
relevant macros as required.
Link: https://lkml.kernel.org/r/20230323060121.1175830-1-chaitanyas.prakash@arm.com
Link: https://lkml.kernel.org/r/20230323060121.1175830-2-chaitanyas.prakash@arm.com
Signed-off-by: Chaitanya S Prakash <chaitanyas.prakash@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When deleting the netns and recreating a new one while re-adding the
veth interface, there is a small window of time during which the old
veth interface has not yet been removed. This can cause the new addition
to fail. To resolve this issue, we can either wait for a short while to
ensure that the old veth interface is deleted, or we can specifically
remove the veth interface.
Before this patch:
# ./rps_default_mask.sh
empty rps_default_mask [ ok ]
changing rps_default_mask dont affect existing devices [ ok ]
changing rps_default_mask dont affect existing netns [ ok ]
changing rps_default_mask affect newly created devices [ ok ]
changing rps_default_mask don't affect newly child netns[II][ ok ]
rps_default_mask is 0 by default in child netns [ ok ]
RTNETLINK answers: File exists
changing rps_default_mask in child ns don't affect the main one[ ok ]
cat: /sys/class/net/vethC11an1/queues/rx-0/rps_cpus: No such file or directory
changing rps_default_mask in child ns affects new childns devices./rps_default_mask.sh: line 36: [: -eq: unary operator expected
[fail] expected 1 found
changing rps_default_mask in child ns don't affect existing devices[ ok ]
After this patch:
# ./rps_default_mask.sh
empty rps_default_mask [ ok ]
changing rps_default_mask dont affect existing devices [ ok ]
changing rps_default_mask dont affect existing netns [ ok ]
changing rps_default_mask affect newly created devices [ ok ]
changing rps_default_mask don't affect newly child netns[II][ ok ]
rps_default_mask is 0 by default in child netns [ ok ]
changing rps_default_mask in child ns don't affect the main one[ ok ]
changing rps_default_mask in child ns affects new childns devices[ ok ]
changing rps_default_mask in child ns don't affect existing devices[ ok ]
Fixes: 3a7d84eae0 ("self-tests: more rps self tests")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20230404072411.879476-1-liuhangbin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
During the development of the maple tree, the strategy of freeing multiple
nodes changed and, in the process, the pivots were reused to store
pointers to dead nodes. To ensure the readers see accurate pivots, the
writers need to mark the nodes as dead and call smp_wmb() to ensure any
readers can identify the node as dead before using the pivot values.
There were two places where the old method of marking the node as dead
without smp_wmb() were being used, which resulted in RCU readers seeing
the wrong pivot value before seeing the node was dead. Fix this race
condition by using mte_set_node_dead() which has the smp_wmb() call to
ensure the race is closed.
Add a WARN_ON() to the ma_free_rcu() call to ensure all nodes being freed
are marked as dead to ensure there are no other call paths besides the two
updated paths.
This is necessary for the RCU mode of the maple tree.
Link: https://lkml.kernel.org/r/20230227173632.3292573-6-surenb@google.com
Fixes: 54a611b605 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In some cases the loopback latency might be large enough, causing
the assertion on invocations to be run before ingress prog getting
executed. The assertion would fail and the test would flake.
This can be reliably reproduced by arbitrarily increasing the
loopback latency (thanks to [1]):
tc qdisc add dev lo root handle 1: htb default 12
tc class add dev lo parent 1:1 classid 1:12 htb rate 20kbps ceil 20kbps
tc qdisc add dev lo parent 1:12 netem delay 100ms
Fix this by waiting on the receive end, instead of instantly
returning to the assert. The call to read() will wait for the
default SO_RCVTIMEO timeout of 3 seconds provided by
start_server().
[1] https://gist.github.com/kstevens715/4598301
Reported-by: Martin KaFai Lau <martin.lau@linux.dev>
Link: https://lore.kernel.org/bpf/9c5c8b7e-1d89-a3af-5400-14fde81f4429@linux.dev/
Fixes: 3573f38401 ("selftests/bpf: Test CGROUP_STORAGE behavior on shared egress + ingress")
Acked-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Link: https://lore.kernel.org/r/20230405193354.1956209-1-zhuyifei@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Fix flaky STATS_RX_DROPPED test. The receiver calls getsockopt after
receiving the last (valid) packet which is not the final packet sent in
the test (valid and invalid packets are sent in alternating fashion with
the final packet being invalid). Since the last packet may or may not
have been dropped already, both outcomes must be allowed.
This issue could also be fixed by making sure the last packet sent is
valid. This alternative is left as an exercise to the reader (or the
benevolent maintainers of this file).
This problem was quite visible on certain setups. On one machine this
failure was observed 50% of the time.
Also, remove a redundant assignment of pkt_stream->nb_pkts. This field
is already initialized by __pkt_stream_alloc.
Fixes: 27e934bec3 ("selftests: xsk: make stat tests not spin on getsockopt")
Signed-off-by: Kal Conley <kal.conley@dectris.com>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230403120400.31018-1-kal.conley@dectris.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This change fixes flakiness in the BIDIRECTIONAL test:
# [is_pkt_valid] expected length [60], got length [90]
not ok 1 FAIL: SKB BUSY-POLL BIDIRECTIONAL
When IPv6 is enabled, the interface will periodically send MLDv1 and
MLDv2 packets. These packets can cause the BIDIRECTIONAL test to fail
since it uses VETH0 for RX.
For other tests, this was not a problem since they only receive on VETH1
and IPv6 was already disabled on VETH0.
Fixes: a89052572e ("selftests/bpf: Xsk selftests framework")
Signed-off-by: Kal Conley <kal.conley@dectris.com>
Link: https://lore.kernel.org/r/20230405082905.6303-1-kal.conley@dectris.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
On some platforms, the console is not the first serial port. To make
this work, the first serial port in QEMU must be set to "null".
Add support for this by adding an optional "serial" parameter, which
defaults to "stdio", and can be overridden by platform-specific
configuration.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
bpf_testmod.ko sometimes fails to build from a clean checkout:
BTF [M] linux/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.ko
/bin/sh: 1: linux-build//tools/build/resolve_btfids/resolve_btfids: not found
The reason is that RESOLVE_BTFIDS may not yet be built. Fix by adding a
dependency.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230403172935.1553022-1-iii@linux.ibm.com
The following selftest patch requires both the bug fixes and the
improvements of the selftest framework.
* iommufd/for-rc:
iommufd: Do not corrupt the pfn list when doing batch carry
iommufd: Fix unpinning of pages when an access is present
iommufd: Check for uptr overflow
Linux 6.3-rc5
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This updates expected return values for invalid buffer test. Now such
values are returned from transport, not from af_vsock.c.
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
We need the fixes in here for testing, as well as the driver core
changes for documentation updates to build on.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In commit 22df776a9a ("tasks: Extract rcu_users out of union"), the
'refcount_t rcu_users' field was extracted out of a union with the
'struct rcu_head rcu' field. This allows us to safely perform a
refcount_inc_not_zero() on task->rcu_users when acquiring a reference on
a task struct. A prior patch leveraged this by making struct task_struct
an RCU-protected object in the verifier, and by bpf_task_acquire() to
use the task->rcu_users field for synchronization.
Now that we can use RCU to protect tasks, we no longer need
bpf_task_kptr_get(), or bpf_task_acquire_not_zero(). bpf_task_kptr_get()
is truly completely unnecessary, as we can just use RCU to get the
object. bpf_task_acquire_not_zero() is now equivalent to
bpf_task_acquire().
In addition to these changes, this patch also updates the associated
selftests to no longer use these kfuncs.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230331195733.699708-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
struct task_struct objects are a bit interesting in terms of how their
lifetime is protected by refcounts. task structs have two refcount
fields:
1. refcount_t usage: Protects the memory backing the task struct. When
this refcount drops to 0, the task is immediately freed, without
waiting for an RCU grace period to elapse. This is the field that
most callers in the kernel currently use to ensure that a task
remains valid while it's being referenced, and is what's currently
tracked with bpf_task_acquire() and bpf_task_release().
2. refcount_t rcu_users: A refcount field which, when it drops to 0,
schedules an RCU callback that drops a reference held on the 'usage'
field above (which is acquired when the task is first created). This
field therefore provides a form of RCU protection on the task by
ensuring that at least one 'usage' refcount will be held until an RCU
grace period has elapsed. The qualifier "a form of" is important
here, as a task can remain valid after task->rcu_users has dropped to
0 and the subsequent RCU gp has elapsed.
In terms of BPF, we want to use task->rcu_users to protect tasks that
function as referenced kptrs, and to allow tasks stored as referenced
kptrs in maps to be accessed with RCU protection.
Let's first determine whether we can safely use task->rcu_users to
protect tasks stored in maps. All of the bpf_task* kfuncs can only be
called from tracepoint, struct_ops, or BPF_PROG_TYPE_SCHED_CLS, program
types. For tracepoint and struct_ops programs, the struct task_struct
passed to a program handler will always be trusted, so it will always be
safe to call bpf_task_acquire() with any task passed to a program.
Note, however, that we must update bpf_task_acquire() to be KF_RET_NULL,
as it is possible that the task has exited by the time the program is
invoked, even if the pointer is still currently valid because the main
kernel holds a task->usage refcount. For BPF_PROG_TYPE_SCHED_CLS, tasks
should never be passed as an argument to the any program handlers, so it
should not be relevant.
The second question is whether it's safe to use RCU to access a task
that was acquired with bpf_task_acquire(), and stored in a map. Because
bpf_task_acquire() now uses task->rcu_users, it follows that if the task
is present in the map, that it must have had at least one
task->rcu_users refcount by the time the current RCU cs was started.
Therefore, it's safe to access that task until the end of the current
RCU cs.
With all that said, this patch makes struct task_struct is an
RCU-protected object. In doing so, we also change bpf_task_acquire() to
be KF_ACQUIRE | KF_RCU | KF_RET_NULL, and adjust any selftests as
necessary. A subsequent patch will remove bpf_task_kptr_get(), and
bpf_task_acquire_not_zero() respectively.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230331195733.699708-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Dual-license veristat.c to dual GPL-2.0-only or BSD-2-Clause license.
This is needed to mirror it to Github to make it convenient for distro
packagers to package veristat as a separate package.
Veristat grew into a useful tool by itself, and there are already
a bunch of users relying on veristat as generic BPF loading and
verification helper tool. So making it easy to packagers by providing
Github mirror just like we do for bpftool and libbpf is the next step to
get veristat into the hands of users.
Apart from few typo fixes, I'm the sole contributor to veristat.c so
far, so no extra Acks should be needed for relicensing.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230331222405.3468634-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The fork function in gcc is considered a built in function due to
being used by libgcov when building with gnu extensions.
Rename fork to sched_process_fork to prevent this conflict.
See details:
d1c3882392https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82457
Fixes the following error:
In file included from progs/bench_local_storage_create.c:6:
progs/bench_local_storage_create.c:43:14: error: conflicting types for
built-in function 'fork'; expected 'int(void)'
[-Werror=builtin-declaration-mismatch]
43 | int BPF_PROG(fork, struct task_struct *parent, struct
task_struct *child)
| ^~~~
Fixes: cbe9d93d58 ("selftests/bpf: Add bench for task storage creation")
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230331075848.1642814-1-james.hilliard1@gmail.com
