FAT-fs (loop3): error, invalid access to FAT (entry 0x00000020)
FAT-fs (loop3): error, fat_get_cluster: invalid cluster chain (i_pos 16)
device nr0
 entered promiscuous mode
FAT-fs (loop3): error, fat_free: invalid cluster chain (i_pos 16)
FAT-fs (loop3): error, fat_get_cluster: invalid cluster chain (i_pos 16)
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
kobject: 'tx-3' (0000000093c0be24): kobject_add_internal: parent: 'queues', set: 'queues'
PGD 1c7e35067 P4D 1c7e35067 PUD 1c22aa067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5804 Comm: syz-executor1 Not tainted 4.19.0-rc7+ #275
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:          (null)
Code: Bad RIP value.
RSP: 0018:ffff8801daf07868 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff860ad93f
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8801baf6c5d8
RBP: ffff8801daf07df8 R08: ffff8801d32d2080 R09: 0000000000000000
R10: fffffbfff145fa09 R11: 0000000000000001 R12: 0000000000000001
FAT-fs (loop3): error, fat_free: invalid cluster chain (i_pos 16)
R13: dffffc0000000000 R14: ffff8801daf07dd0 R15: ffff8801baf6c5d8
FS:  00007f25096a8700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001bafa3000 CR4: 00000000001426e0
kobject: 'tx-3' (0000000093c0be24): kobject_uevent_env
Call Trace:
 <IRQ>
kobject: 'tx-3' (0000000093c0be24): fill_kobj_path: path = '/devices/virtual/net/nr0
/queues/tx-3'
kobject: 'rx-3' (0000000000a2fd15): kobject_add_internal: parent: 'queues', set: 'queues'
kobject: 'rx-3' (0000000000a2fd15): kobject_uevent_env
kobject: 'rx-3' (0000000000a2fd15): fill_kobj_path: path = '/devices/virtual/net/nr0
/queues/rx-3'
kobject: 'loop5' (00000000b9cfdca0): kobject_uevent_env
 __do_softirq+0x30b/0xad8 kernel/softirq.c:292
kobject: 'loop5' (00000000b9cfdca0): fill_kobj_path: path = '/devices/virtual/block/loop5'
kobject: 'loop3' (000000001e77bdd0): kobject_uevent_env
kobject: 'loop3' (000000001e77bdd0): fill_kobj_path: path = '/devices/virtual/block/loop3'
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1047
 </IRQ>
 do_softirq.part.13+0x126/0x160 kernel/softirq.c:336
 do_softirq kernel/softirq.c:328 [inline]
 __local_bh_enable_ip+0x21d/0x260 kernel/softirq.c:189
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 tun_get_user+0x1c0b/0x4250 drivers/net/tun.c:1938
 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1968
 call_write_iter include/linux/fs.h:1808 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x6b8/0x9f0 fs/read_write.c:487
 vfs_write+0x1fc/0x560 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f25096a7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457579
RDX: 0000000000000012 RSI: 0000000020000000 RDI: 0000000000000009
RBP: 000000000072c0e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f25096a86d4
R13: 00000000004c5574 R14: 00000000004d8e98 R15: 00000000ffffffff
Modules linked in:
CR2: 0000000000000000
---[ end trace e163547d7be2b4ae ]---
RIP: 0010:          (null)
Code: Bad RIP value.
RSP: 0018:ffff8801daf07868 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff860ad93f
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8801baf6c5d8
RBP: ffff8801daf07df8 R08: ffff8801d32d2080 R09: 0000000000000000
R10: fffffbfff145fa09 R11: 0000000000000001 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff8801daf07dd0 R15: ffff8801baf6c5d8
FS:  00007f25096a8700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001bafa3000 CR4: 00000000001426e0