[moderation] [kernel?] KCSAN: data-race in do_notify_parent_cldstop / do_signal_stop (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 39133352cbed Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14579002180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7507056e4ee79a
dashboard link: https://syzkaller.appspot.com/bug?extid=b1435d499ce6d75d1d85
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [linux-...@vger.kernel.org lu...@kernel.org pet...@infradead.org tg...@linutronix.de]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/da67c50a8865/disk-39133352.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4ec0da5364e5/vmlinux-39133352.xz
kernel image: https://storage.googleapis.com/syzbot-assets/29aba2ced196/bzImage-39133352.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b1435d...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in do_notify_parent_cldstop / do_signal_stop

write to 0xffff8881031f9260 of 4 bytes by task 17783 on cpu 0:
do_signal_stop+0x10c/0x600 kernel/signal.c:2456
get_signal+0x5f5/0x10a0 kernel/signal.c:2845
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
syscall_exit_to_user_mode+0x58/0x130 kernel/entry/common.c:212
do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881031f9260 of 4 bytes by task 17780 on cpu 1:
do_notify_parent_cldstop+0x192/0x2a0 kernel/signal.c:2186
get_signal+0xa60/0x10a0 kernel/signal.c:2713
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
syscall_exit_to_user_mode+0x58/0x130 kernel/entry/common.c:212
do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000000 -> 0x00000014

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17780 Comm: syz-executor.4 Not tainted 6.8.0-rc5-syzkaller-00029-g39133352cbed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.