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Eric Dumazet 3d6d414b21 l2tp: avoid one data-race in l2tp_tunnel_del_work()
[ Upstream commit 7a29f6bf60 ]

We should read sk->sk_socket only when dealing with kernel sockets.

syzbot reported the following data-race:

BUG: KCSAN: data-race in l2tp_tunnel_del_work / sk_common_release

write to 0xffff88811c182b20 of 8 bytes by task 5365 on cpu 0:
  sk_set_socket include/net/sock.h:2092 [inline]
  sock_orphan include/net/sock.h:2118 [inline]
  sk_common_release+0xae/0x230 net/core/sock.c:4003
  udp_lib_close+0x15/0x20 include/net/udp.h:325
  inet_release+0xce/0xf0 net/ipv4/af_inet.c:437
  __sock_release net/socket.c:662 [inline]
  sock_close+0x6b/0x150 net/socket.c:1455
  __fput+0x29b/0x650 fs/file_table.c:468
  ____fput+0x1c/0x30 fs/file_table.c:496
  task_work_run+0x131/0x1a0 kernel/task_work.c:233
  resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
  __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
  exit_to_user_mode_loop+0x1fe/0x740 kernel/entry/common.c:75
  __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
  syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
  syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
  syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
  do_syscall_64+0x1e1/0x2b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811c182b20 of 8 bytes by task 827 on cpu 1:
  l2tp_tunnel_del_work+0x2f/0x1a0 net/l2tp/l2tp_core.c:1418
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
  worker_thread+0x582/0x770 kernel/workqueue.c:3421
  kthread+0x489/0x510 kernel/kthread.c:463
  ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0xffff88811b818000 -> 0x0000000000000000

Fixes: d00fa9adc5 ("l2tp: fix races with tunnel socket close")
Reported-by: syzbot+7312e82745f7fa2526db@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6968b029.050a0220.58bed.0016.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Link: https://patch.msgid.link/20260115092139.3066180-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-01-30 10:28:39 +01:00
arch arm64: dts: qcom: sc8280xp: Add missing VDD_MXC links 2026-01-30 10:28:37 +01:00
block block: fix NULL pointer dereference in blk_zone_reset_all_bio_endio() 2026-01-08 10:15:06 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: seqiv - Do not use req->iv after crypto_aead_encrypt 2026-01-08 10:14:32 +01:00
Documentation fou: Don't allow 0 for FOU_ATTR_IPPROTO. 2026-01-30 10:28:39 +01:00
drivers veth: fix data race in veth_get_ethtool_stats 2026-01-30 10:28:39 +01:00
fs btrfs: fix missing fields in superblock backup with BLOCK_GROUP_TREE 2026-01-30 10:28:37 +01:00
include dt-bindings: power: qcom,rpmpd: Add SC8280XP_MXC_AO 2026-01-30 10:28:37 +01:00
init init: handle bootloader identifier in kernel parameters 2025-10-19 16:33:50 +02:00
io_uring io_uring: move local task_work in exit cancel loop 2026-01-23 11:18:42 +01:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel ptp: Add PHC file mode checks. Allow RO adjtime() without FMODE_WRITE. 2026-01-30 10:28:37 +01:00
lib lib/buildid: use __kernel_read() for sleepable context 2026-01-23 11:18:43 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/page_alloc: prevent pcp corruption with SMP=n 2026-01-23 11:18:52 +01:00
net l2tp: avoid one data-race in l2tp_tunnel_del_work() 2026-01-30 10:28:39 +01:00
rust rust: kbuild: workaround rustdoc doctests modifier bug 2025-11-24 10:36:07 +01:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:14:50 +01:00
scripts kbuild: fix compilation of dtb specified on command-line without make rule 2026-01-08 10:14:34 +01:00
security tpm2-sessions: Fix out of range indexing in name_size 2026-01-17 16:31:29 +01:00
sound ASoC: codecs: wsa881x: fix unnecessary initialisation 2026-01-23 11:18:45 +01:00
tools tools: ynl: Specify --no-line-number in ynl-regen.sh. 2026-01-30 10:28:39 +01:00
usr kbuild: uapi: Strip comments before size type check 2025-11-13 15:34:35 -05:00
virt KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot 2026-01-08 10:14:21 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS staging: rtl8712: Remove driver using deprecated API wext 2025-12-07 06:25:02 +09:00
Makefile Linux 6.12.67 2026-01-23 11:18:52 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.