[moderation] [wireguard?] KCSAN: data-race in __mod_timer / __mod_timer (11)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b69053dd3ffb wifi: mt76: Remove blank line after mt792x fi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1016d29a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b319ff1b6a2797ca
dashboard link: https://syzkaller.appspot.com/bug?extid=e3c3c366a6a932e8b7b5
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [Ja...@zx2c4.com andrew...@lunn.ch da...@davemloft.net edum...@google.com ku...@kernel.org linux-...@vger.kernel.org net...@vger.kernel.org pab...@redhat.com wire...@lists.zx2c4.com]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3a0f5632025b/disk-b69053dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c67de396f055/vmlinux-b69053dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0824b8a30f27/bzImage-b69053dd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e3c3c3...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __mod_timer / __mod_timer

write to 0xffff88811a6e0a80 of 8 bytes by task 3495 on cpu 0:
__mod_timer+0x784/0x840 kernel/time/timer.c:1078
mod_timer+0x1f/0x30 kernel/time/timer.c:1195
mod_peer_timer drivers/net/wireguard/timers.c:37 [inline]
wg_timers_any_authenticated_packet_traversal+0xd0/0x100 drivers/net/wireguard/timers.c:218
wg_packet_create_data_done drivers/net/wireguard/send.c:247 [inline]
wg_packet_tx_worker+0xeb/0x330 drivers/net/wireguard/send.c:276
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

read to 0xffff88811a6e0a80 of 8 bytes by task 13174 on cpu 1:
__mod_timer+0x69/0x840 kernel/time/timer.c:1038
mod_timer+0x1f/0x30 kernel/time/timer.c:1195
mod_peer_timer drivers/net/wireguard/timers.c:37 [inline]
wg_timers_any_authenticated_packet_traversal+0xd0/0x100 drivers/net/wireguard/timers.c:218
wg_packet_consume_data_done drivers/net/wireguard/receive.c:354 [inline]
wg_packet_rx_poll+0x7f5/0x1160 drivers/net/wireguard/receive.c:474
__napi_poll+0x5f/0x300 net/core/dev.c:7668
napi_threaded_poll_loop+0x1ac/0x630 net/core/dev.c:7787
napi_threaded_poll+0x164/0x200 net/core/dev.c:7838
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: 0x00000000fffffb88 -> 0x00000000fffffb8b

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13174 Comm: napi/wg2-0 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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