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BUG: KCSAN: data-race in blkdev_get_by_dev / blkdev_put

write to 0xffff88810053a0a8 of 4 bytes by task 4698 on cpu 0:
 blkdev_get_by_dev+0xa58/0xcf0
 blkdev_get_by_path+0x117/0x220 block/bdev.c:878
 mount_bdev+0x47/0x290 fs/super.c:1325
 msdos_mount+0x2d/0x40 fs/fat/namei_msdos.c:662
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1497
 do_new_mount fs/namespace.c:3024 [inline]
 path_mount+0x11cf/0x1c40 fs/namespace.c:3354
 do_mount fs/namespace.c:3367 [inline]
 __do_sys_mount fs/namespace.c:3575 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3552
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3552
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810053a0a8 of 4 bytes by task 3870 on cpu 1:
 blkdev_put+0x3b/0x4a0 block/bdev.c:899
 blkdev_close+0x32/0x40 block/fops.c:517
 __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
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000003 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3870 Comm: udevd Not tainted 5.17.0-rc7-syzkaller-00241-gf0e18b03fcaf-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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