[moderation] [fs?] [mm?] KCSAN: data-race in bprm_execve / copy_fs (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 96fca68c4fbf Merge tag 'nfsd-6.9-3' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=118618f7180000
kernel config: https://syzkaller.appspot.com/x/.config?x=eaea34ec4c9b6fb6
dashboard link: https://syzkaller.appspot.com/bug?extid=8aa70b98cc46b42f3b46
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org ebie...@xmission.com ja...@suse.cz kees...@chromium.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@kvack.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c847bdb99fa5/disk-96fca68c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7f1451b82626/vmlinux-96fca68c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dc96a83503e5/bzImage-96fca68c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8aa70b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in bprm_execve / copy_fs

write to 0xffff8881040db0d0 of 4 bytes by task 17380 on cpu 0:
bprm_execve+0x971/0xc60 fs/exec.c:1897
do_execveat_common+0x768/0x7d0 fs/exec.c:1979
do_execveat fs/exec.c:2064 [inline]
__do_sys_execveat fs/exec.c:2138 [inline]
__se_sys_execveat fs/exec.c:2132 [inline]
__x64_sys_execveat+0x75/0x90 fs/exec.c:2132
x64_sys_call+0x2b9f/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:323
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881040db0d0 of 4 bytes by task 17375 on cpu 1:
copy_fs+0x95/0xf0 kernel/fork.c:1754
copy_process+0xe6c/0x1f80 kernel/fork.c:2380
create_io_thread+0x9e/0xd0 kernel/fork.c:2744
create_worker_cont+0x5b/0x350 io_uring/io-wq.c:774
task_work_run+0x13a/0x1a0 kernel/task_work.c:180
get_signal+0xeee/0x1080 kernel/signal.c:2683
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:218
do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17375 Comm: syz-executor.4 Tainted: G W 6.9.0-rc4-syzkaller-00031-g96fca68c4fbf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


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