Hello,
syzbot found the following issue on:
HEAD commit: b6505459 Linux 5.10-rc6
git tree: upstream
console output:
https://syzkaller.appspot.com/x/log.txt?x=102c103d500000
kernel config:
https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link:
https://syzkaller.appspot.com/bug?extid=3cf231e9e732c716afe4
compiler: clang version 12.0.0 (
https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [
ax...@kernel.dk chri...@brauner.io ebie...@xmission.com linux-...@vger.kernel.org liuzhi...@huawei.com ol...@redhat.com]
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+3cf231...@syzkaller.appspotmail.com
==================================================================
BUG: KCSAN: data-race in exit_signals / kthread_unpark
read-write to 0xffff88805163c064 of 4 bytes by task 21373 on cpu 1:
exit_signals+0x102/0x530 kernel/signal.c:2846
do_exit+0x15d/0x1630 kernel/exit.c:765
kthread+0x205/0x220 kernel/kthread.c:294
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
read to 0xffff88805163c064 of 4 bytes by task 21267 on cpu 0:
to_kthread kernel/kthread.c:83 [inline]
kthread_unpark+0x1f/0x140 kernel/kthread.c:511
kthread_stop+0xa6/0x2c0 kernel/kthread.c:594
loop_unprepare_queue drivers/block/loop.c:932 [inline]
__loop_clr_fd+0x424/0x5a0 drivers/block/loop.c:1266
lo_release+0x101/0x130 drivers/block/loop.c:1927
__blkdev_put+0x370/0x4a0 fs/block_dev.c:1782
blkdev_put+0x1d9/0x200 fs/block_dev.c:1844
blkdev_close+0x47/0x50 fs/block_dev.c:1851
__fput+0x243/0x4d0 fs/file_table.c:281
____fput+0x11/0x20 fs/file_table.c:314
task_work_run+0x8e/0x110 kernel/task_work.c:151
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
exit_to_user_mode_prepare+0x13c/0x170 kernel/entry/common.c:191
syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21267 Comm: systemd-udevd Not tainted 5.10.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
---
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