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Martin KaFai Lau 76cf409aa7 tcp: seq_file: Avoid skipping sk during tcp_seek_last_pos
[ Upstream commit 525e2f9fd0229eb10cb460a9e6d978257f24804e ]

st->bucket stores the current bucket number.
st->offset stores the offset within this bucket that is the sk to be
seq_show().  Thus, st->offset only makes sense within the same
st->bucket.

These two variables are an optimization for the common no-lseek case.
When resuming the seq_file iteration (i.e. seq_start()),
tcp_seek_last_pos() tries to continue from the st->offset
at bucket st->bucket.

However, it is possible that the bucket pointed by st->bucket
has changed and st->offset may end up skipping the whole st->bucket
without finding a sk.  In this case, tcp_seek_last_pos() currently
continues to satisfy the offset condition in the next (and incorrect)
bucket.  Instead, regardless of the offset value, the first sk of the
next bucket should be returned.  Thus, "bucket == st->bucket" check is
added to tcp_seek_last_pos().

The chance of hitting this is small and the issue is a decade old,
so targeting for the next tree.

Fixes: a8b690f98b ("tcp: Fix slowness in read /proc/net/tcp")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210701200541.1033917-1-kafai@fb.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-07-05 19:11:19 +02:00
arch arm64: dts: renesas: r8a77995: draak: Remove bogus adv7511w properties 2024-07-05 19:10:52 +02:00
block blk-crypto: fix check for too-large dun_bytes 2024-07-05 19:10:30 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2024-07-05 19:10:21 +02:00
crypto init: add dsm gpl source 2024-07-05 18:00:04 +02:00
Documentation dt-bindings: sifive-l2-cache: Fix 'select' matching 2024-07-05 19:00:49 +02:00
drivers drm/amdgpu/acp: Make PM domain really work 2024-07-05 19:11:19 +02:00
fs gfs2: Fix memory leak of object lsi on error return path 2024-07-05 19:10:52 +02:00
include bpf: Fix a typo of reuseport map in bpf.h. 2024-07-05 19:10:44 +02:00
init init: add dsm gpl source 2024-07-05 18:00:04 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-26 12:06:54 +02:00
kernel bpf: Fix potential memleak and UAF in the verifier. 2024-07-05 19:10:44 +02:00
lib lib/mpi: use kcalloc in mpi_resize 2024-07-05 19:10:07 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/page_alloc: speed up the iteration of max_order 2024-07-05 19:06:11 +02:00
net tcp: seq_file: Avoid skipping sk during tcp_seek_last_pos 2024-07-05 19:11:19 +02:00
samples samples/bpf: Fix the error return code of xdp_redirect's main() 2021-07-14 16:56:23 +02:00
scripts scripts/tracing: fix the bug that can't parse raw_trace_func 2024-07-05 18:52:27 +02:00
security bpf: Add lockdown check for probe_write_user helper 2024-07-05 18:53:10 +02:00
sound ASoC: mediatek: mt8183: Fix Unbalanced pm_runtime_enable in mt8183_afe_pcm_dev_probe 2024-07-05 19:10:36 +02:00
SynoBuildConf init: add dsm gpl source 2024-07-05 18:00:04 +02:00
synology init: add dsm gpl source 2024-07-05 18:00:04 +02:00
tools libbpf: Fix removal of inner map in bpf_object__create_map 2024-07-05 19:10:52 +02:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: Do not leak memory for duplicate debugfs directories 2024-07-05 18:52:31 +02:00
.clang-format init: add dsm gpl source 2024-07-05 18:00:04 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS init: add dsm gpl source 2024-07-05 18:00:04 +02:00
Makefile init: add dsm gpl source 2024-07-05 18:00:04 +02:00
README

Linux kernel
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