[moderation] [kernel?] KCSAN: data-race in kick_pool_pick / wq_worker_running

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cf62c7084acf Merge tag 'execve-v7.3-rc1' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1210de79580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4a7ca465965e5caa
dashboard link: https://syzkaller.appspot.com/bug?extid=8922e6b8343f70be92e8
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [anna-...@linutronix.de fred...@kernel.org linux-...@vger.kernel.org tg...@kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/51522d89998c/disk-cf62c708.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd5a764875f8/vmlinux-cf62c708.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a037ded41b7/bzImage-cf62c708.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8922e6...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in kick_pool_pick / wq_worker_running

read-write to 0xffff888237c2abe4 of 4 bytes by task 10314 on cpu 0:
wq_worker_running+0x9c/0x120 kernel/workqueue.c:1465
schedule_timeout+0xca/0x180 kernel/time/sleep_timeout.c:99
schedule_timeout_uninterruptible kernel/time/sleep_timeout.c:158 [inline]
msleep+0x4f/0x90 kernel/time/sleep_timeout.c:318
nsim_fib6_rt_add drivers/net/netdevsim/fib.c:693 [inline]
nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:759 [inline]
nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
nsim_fib_event+0x4544/0x4de0 drivers/net/netdevsim/fib.c:889
nsim_fib_event_work+0x133/0x200 drivers/net/netdevsim/fib.c:1493
process_one_work kernel/workqueue.c:3387 [inline]
process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3470
worker_thread+0x569/0x750 kernel/workqueue.c:3551
kthread+0x223/0x270 kernel/kthread.c:436
ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888237c2abe4 of 4 bytes by task 3388 on cpu 1:
need_more_worker kernel/workqueue.c:954 [inline]
kick_pool_pick+0x5f/0x310 kernel/workqueue.c:1284
__queue_work+0x90a/0xbc0 kernel/workqueue.c:2449
queue_work_on+0xa9/0x140 kernel/workqueue.c:2501
srcu_queue_delayed_work_on kernel/rcu/srcutree.c:873 [inline]
srcu_schedule_cbs_sdp kernel/rcu/srcutree.c:886 [inline]
srcu_gp_end kernel/rcu/srcutree.c:951 [inline]
srcu_advance_state kernel/rcu/srcutree.c:1869 [inline]
process_srcu+0xa39/0xd90 kernel/rcu/srcutree.c:1973
process_one_work kernel/workqueue.c:3387 [inline]
process_scheduled_works+0x56a/0xa50 kernel/workqueue.c:3470
worker_thread+0x569/0x750 kernel/workqueue.c:3551
kthread+0x223/0x270 kernel/kthread.c:436
ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3388 Comm: kworker/1:5 Not tainted syzkaller #0 PREEMPT(lazy)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: rcu_gp process_srcu
==================================================================


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