KCSAN: data-race in do_exit / futex_wait_queue_me (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3d5e28bf Merge branch 'stable/for-linus-5.10-rc2' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=179c64e2500000
kernel config: https://syzkaller.appspot.com/x/.config?x=671e27f23e60a67b
dashboard link: https://syzkaller.appspot.com/bug?extid=5d5fd1007b1fd0a5fa9b
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+5d5fd1...@syzkaller.appspotmail.com

binder: 22547:22549 ioctl c018620c 0 returned -14
==================================================================
BUG: KCSAN: data-race in do_exit / futex_wait_queue_me

read-write to 0xffff88802459c064 of 4 bytes by task 22547 on cpu 1:
freezer_count include/linux/freezer.h:121 [inline]
freezable_schedule include/linux/freezer.h:173 [inline]
futex_wait_queue_me+0x198/0x240 kernel/futex.c:2603
futex_wait+0x145/0x390 kernel/futex.c:2705
do_futex+0x10ff/0x2140 kernel/futex.c:3764
__do_sys_futex kernel/futex.c:3827 [inline]
__se_sys_futex+0x2a8/0x390 kernel/futex.c:3793
__x64_sys_futex+0x74/0x80 kernel/futex.c:3793
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88802459c064 of 4 bytes by task 22549 on cpu 0:
find_alive_thread kernel/exit.c:496 [inline]
find_new_reaper kernel/exit.c:545 [inline]
forget_original_parent kernel/exit.c:620 [inline]
exit_notify kernel/exit.c:653 [inline]
do_exit+0x530/0x15a0 kernel/exit.c:829
do_group_exit+0x16f/0x170 kernel/exit.c:906
__do_sys_exit_group+0xb/0x10 kernel/exit.c:917
__se_sys_exit_group+0x5/0x10 kernel/exit.c:915
__x64_sys_exit_group+0x16/0x20 kernel/exit.c:915
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: 22549 Comm: syz-executor.0 Not tainted 5.10.0-rc3-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.