------------[ cut here ]------------
WARNING: CPU: 0 PID: 13421 at fs/block_dev.c:1634 blkdev_put+0x4c8/0x560 fs/block_dev.c:1634
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 13421 Comm: syz-executor6 Not tainted 4.9.109-ge1815b3 #49
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801caf6fa10 ffffffff81eb3e29 ffffffff83c48960 00000000ffffffff
 0000000000000000 0000000000000000 0000000000000662 ffff8801caf6fad0
 ffffffff81421925 0000000041b58ab3 ffffffff843b9a40 ffffffff81421766
Call Trace:
 [<ffffffff81eb3e29>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3e29>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81421925>] panic+0x1bf/0x3bc kernel/panic.c:179
 [<ffffffff81421c11>] __warn.cold.9+0xc1/0x17f kernel/panic.c:542
 [<ffffffff811367cc>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
 [<ffffffff816323b8>] blkdev_put+0x4c8/0x560 fs/block_dev.c:1634
 [<ffffffff81e5744b>] blkdev_bszset block/ioctl.c:495 [inline]
 [<ffffffff81e5744b>] blkdev_ioctl+0x1db/0x1a70 block/ioctl.c:560
 [<ffffffff81632b8e>] block_ioctl+0xde/0x120 fs/block_dev.c:1688
 [<ffffffff815b2b9c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b2b9c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b2b9c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b3c1f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b3c1f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9993>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..