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BUG: KCSAN: data-race in blkdev_get_by_dev / blkdev_put

write to 0xffff8881004236a8 of 4 bytes by task 6864 on cpu 1:
 blkdev_get_by_dev+0x9a6/0xc60
 blkdev_open+0xb3/0x140 block/fops.c:498
 do_dentry_open+0x52c/0x840 fs/open.c:824
 vfs_open+0x43/0x50 fs/open.c:958
 do_open fs/namei.c:3476 [inline]
 path_openat+0x170c/0x1f30 fs/namei.c:3609
 do_filp_open+0x105/0x220 fs/namei.c:3636
 do_sys_openat2+0xb5/0x2b0 fs/open.c:1213
 do_sys_open fs/open.c:1229 [inline]
 __do_sys_openat fs/open.c:1245 [inline]
 __se_sys_openat fs/open.c:1240 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1240
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x50 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881004236a8 of 4 bytes by task 1828 on cpu 0:
 blkdev_put+0x3b/0x4a0 block/bdev.c:902
 blkdev_close+0x32/0x40 block/fops.c:512
 __fput+0x295/0x520 fs/file_table.c:317
 ____fput+0x11/0x20 fs/file_table.c:350
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:183 [inline]
 exit_to_user_mode_prepare+0x122/0x140 kernel/entry/common.c:215
 __syscall_exit_to_user_mode_work kernel/entry/common.c:297 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:308
 do_syscall_64+0x37/0x50 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000001 -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1828 Comm: syz-executor.1 Not tainted 5.17.0-syzkaller-14079-gbe2d3ecedd99-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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