F2FS-fs (loop4): Can't find valid F2FS filesystem in 1th superblock
F2FS-fs (loop4): Magic Mismatch, valid(0xf2f52010) - read(0x0)
F2FS-fs (loop4): Can't find valid F2FS filesystem in 2th superblock
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 16515 Comm: syz-executor0 Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019a59b000 task.stack: ffff8801c8270000
RIP: 0010:[<ffffffff825c6cad>]  [<ffffffff825c6cad>] loop_validate_file+0x20d/0x400 drivers/block/loop.c:656
RSP: 0018:ffff8801c8277ae0  EFLAGS: 00010206
RAX: 0000000000000036 RBX: dffffc0000000000 RCX: ffffc900008b6000
RDX: 000000000000008d RSI: ffffffff825c6c7d RDI: 00000000000001b0
RBP: ffff8801c8277af8 R08: ffff88019a59b910 R09: 0000000000000001
R10: 0000000000000000 R11: 1ffff100334b371d R12: 0000000000000000
R13: ffff8801cbe1c500 R14: ffff8801cbe1c500 R15: ffff8801b98f0158
FS:  00007f1df3c65700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d321000 CR3: 00000001b67c7000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801b98f0000 0000000000004c00 ffff8801cb833e00 ffff8801c8277b80
 ffffffff825cc6b7 ffff8801c8277b00 0000000200000001 0000000000930000
 ffff8801c8277de0 ffff8801c8277b80 ffff8801b98f0150 1ffff1003904ef6c
Call Trace:
 [<ffffffff825cc6b7>] loop_set_fd drivers/block/loop.c:909 [inline]
 [<ffffffff825cc6b7>] lo_ioctl+0x6a7/0x1690 drivers/block/loop.c:1356
 [<ffffffff81e587e6>] __blkdev_driver_ioctl block/ioctl.c:294 [inline]
 [<ffffffff81e587e6>] blkdev_ioctl+0x7b6/0x1a70 block/ioctl.c:590
 [<ffffffff816330ee>] block_ioctl+0xde/0x120 fs/block_dev.c:1688
 [<ffffffff815b309c>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815b309c>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff815b309c>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff815b411f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815b411f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 00 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 f7 01 00 00 4d 8b a4 24 f0 00 00 00 49 8d bc 24 b0 01 00 00 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 cc 01 00 00 4d 8b a4 24 b0 01 00 00 4c 89 e0 
RIP  [<ffffffff825c6cad>] loop_validate_file+0x20d/0x400 drivers/block/loop.c:656
 RSP <ffff8801c8277ae0>
---[ end trace 2cf41ad132fa8582 ]---