KCSAN: data-race in futex_wait_queue_me / task_dump_owner (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4df91062 mm: memcg: relayout structure mem_cgroup to avoid..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=174260c9500000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9b19d1bde60f8d
dashboard link: https://syzkaller.appspot.com/bug?extid=f58565b98d68a7b60904
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [dvh...@infradead.org linux-...@vger.kernel.org mi...@redhat.com pet...@infradead.org tg...@linutronix.de]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f58565...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in futex_wait_queue_me / task_dump_owner

read-write to 0xffff88803b38e024 of 4 bytes by task 624 on cpu 1:
freezer_do_not_count include/linux/freezer.h:109 [inline]
freezable_schedule include/linux/freezer.h:171 [inline]
futex_wait_queue_me+0x17e/0x240 kernel/futex.c:2604
futex_wait+0x145/0x390 kernel/futex.c:2706
do_futex+0x10ff/0x2140 kernel/futex.c:3765
__do_sys_futex kernel/futex.c:3828 [inline]
__se_sys_futex+0x2a8/0x390 kernel/futex.c:3794
__x64_sys_futex+0x74/0x80 kernel/futex.c:3794
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88803b38e024 of 4 bytes by task 626 on cpu 0:
task_dump_owner+0x2b/0x1b0 fs/proc/base.c:1823
pid_update_inode fs/proc/base.c:1965 [inline]
pid_revalidate+0x69/0x110 fs/proc/base.c:1988
lookup_fast+0x208/0x370 fs/namei.c:768
walk_component+0x5c/0x350 fs/namei.c:1857
link_path_walk+0x451/0x710 fs/namei.c:2180
path_openat+0x19f/0x20a0 fs/namei.c:3365
do_filp_open+0xbd/0x1d0 fs/namei.c:3396
do_sys_openat2+0xa3/0x240 fs/open.c:1168
do_sys_open fs/open.c:1184 [inline]
__do_sys_open fs/open.c:1192 [inline]
__se_sys_open fs/open.c:1188 [inline]
__x64_sys_open+0xe2/0x110 fs/open.c:1188
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 626 Comm: syz-executor.1 Not tainted 5.10.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

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