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BUG: KCSAN: data-race in blkdev_get_whole / blkdev_put

write to 0xffff8881017bf6e0 of 4 bytes by task 8471 on cpu 0:
 blkdev_get_whole+0x308/0x350 fs/block_dev.c:1268
 blkdev_get_by_dev+0x2ad/0x8d0 fs/block_dev.c:1415
 blkdev_open+0xb3/0x130 fs/block_dev.c:1510
 do_dentry_open+0x53e/0x830 fs/open.c:826
 vfs_open+0x43/0x50 fs/open.c:940
 do_open fs/namei.c:3361 [inline]
 path_openat+0x184e/0x20b0 fs/namei.c:3494
 do_filp_open+0xd9/0x1f0 fs/namei.c:3521
 do_sys_openat2+0xa3/0x250 fs/open.c:1195
 do_sys_open fs/open.c:1211 [inline]
 __do_sys_open fs/open.c:1219 [inline]
 __se_sys_open fs/open.c:1215 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1215
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881017bf6e0 of 4 bytes by task 1790 on cpu 1:
 blkdev_put+0x3b/0x4e0 fs/block_dev.c:1529
 blkdev_close+0x47/0x50 fs/block_dev.c:1584
 __fput+0x25b/0x4e0 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302
 do_syscall_64+0x49/0x90 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000001 -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1790 Comm: syz-executor.4 Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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