KCSAN: data-race in __blkdev_put / __blkdev_put

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ac3a0c84 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15781a70900000
kernel config: https://syzkaller.appspot.com/x/.config?x=c9ef42681860b2c5
dashboard link: https://syzkaller.appspot.com/bug?extid=6d19edc6b879bb3188b9
compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project.git ca2dcbd030eadbf0aa9b660efe864ff08af6e18b)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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+6d19ed...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __blkdev_put / __blkdev_put

write to 0xffff888129e29744 of 4 bytes by task 9130 on cpu 1:
__blkdev_put+0x10c/0x4a0 fs/block_dev.c:1892
blkdev_put+0x1e6/0x210 fs/block_dev.c:1963
blkdev_close+0x47/0x50 fs/block_dev.c:1970
__fput+0x1df/0x460 fs/file_table.c:281
____fput+0x11/0x20 fs/file_table.c:314
task_work_run+0x8e/0x110 kernel/task_work.c:135
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop arch/x86/entry/common.c:239 [inline]
__prepare_exit_to_usermode+0x1c6/0x230 arch/x86/entry/common.c:269
__syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:352
do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:393
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888129e29744 of 4 bytes by task 31462 on cpu 0:
__blkdev_put+0x5c/0x4a0 fs/block_dev.c:1885
blkdev_put+0x1e6/0x210 fs/block_dev.c:1963
blkdev_close+0x47/0x50 fs/block_dev.c:1970
__fput+0x1df/0x460 fs/file_table.c:281
____fput+0x11/0x20 fs/file_table.c:314
task_work_run+0x8e/0x110 kernel/task_work.c:135
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop arch/x86/entry/common.c:239 [inline]
__prepare_exit_to_usermode+0x1c6/0x230 arch/x86/entry/common.c:269
__syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:352
do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:393
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 31462 Comm: systemd-udevd Not tainted 5.8.0-rc7-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.