[moderation] [kernel?] KCSAN: data-race in do_exit / zap_pid_ns_processes (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fbfd64d25c7a Merge tag 'vfs-6.13-rc7.fixes' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1492a4b0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9ab3e6c069ff12aa
dashboard link: https://syzkaller.appspot.com/bug?extid=cfe29b0f02f9312132c9
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/05565573a810/disk-fbfd64d2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ab7f10eda1f6/vmlinux-fbfd64d2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e9e23f8269e0/bzImage-fbfd64d2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cfe29b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in do_exit / zap_pid_ns_processes

write to 0xffff888107cee820 of 4 bytes by task 31247 on cpu 1:
reparent_leader kernel/exit.c:669 [inline]
forget_original_parent kernel/exit.c:721 [inline]
exit_notify kernel/exit.c:737 [inline]
do_exit+0xa61/0x17f0 kernel/exit.c:958
do_group_exit+0x102/0x150 kernel/exit.c:1087
get_signal+0xeb9/0x1000 kernel/signal.c:3017
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x62/0x120 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888107cee820 of 4 bytes by task 31248 on cpu 0:
thread_group_leader include/linux/sched/signal.h:701 [inline]
zap_pid_ns_processes+0x3d/0x2c0 kernel/pid_namespace.c:175
find_child_reaper kernel/exit.c:611 [inline]
forget_original_parent kernel/exit.c:700 [inline]
exit_notify kernel/exit.c:737 [inline]
do_exit+0x155d/0x17f0 kernel/exit.c:958
__do_sys_exit kernel/exit.c:1054 [inline]
__se_sys_exit kernel/exit.c:1052 [inline]
__x64_sys_exit+0x1f/0x20 kernel/exit.c:1052
x64_sys_call+0x2da1/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:61
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000011

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 31248 Comm: syz.0.8419 Not tainted 6.13.0-rc6-syzkaller-00036-gfbfd64d25c7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

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