------------[ cut here ]------------
kernel BUG at fs/buffer.c:605!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 7325 Comm: syz-executor.0 Not tainted 4.14.154 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880a5da2340 task.stack: ffff88804ef30000
RIP: 0010:mark_buffer_dirty_inode fs/buffer.c:605 [inline]
RIP: 0010:mark_buffer_dirty_inode+0x2ea/0x3e0 fs/buffer.c:596
RSP: 0018:ffff88804ef37528 EFLAGS: 00010246
RAX: 0000000000040000 RBX: ffff88809a26d7e0 RCX: ffffc90005e3d000
RDX: 0000000000040000 RSI: ffffffff8199d60a RDI: ffff8880888699b8
RBP: ffff88804ef37560 R08: ffff8880a5da2340 R09: 0000000000000003
R10: 0000000000000000 R11: ffff8880a5da2340 R12: ffff888088869858
R13: 0000000000000000 R14: ffff888088a4a720 R15: 0000000000001c9f
FS:  00007f5eddc73700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000713934 CR3: 00000000930b3000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 fat16_ent_put+0xc5/0x100 fs/fat/fatent.c:181
 fat_ent_write+0xc2/0x190 fs/fat/fatent.c:416
 fat_chain_add+0x3ed/0x590 fs/fat/misc.c:128
 fat_add_cluster+0xa1/0xc0 fs/fat/inode.c:105
 __fat_get_block fs/fat/inode.c:147 [inline]
 fat_get_block+0x2d4/0x7e0 fs/fat/inode.c:176
 __block_write_begin_int+0x396/0x1100 fs/buffer.c:2027
 __block_write_begin fs/buffer.c:2077 [inline]
 block_write_begin+0x5f/0x190 fs/buffer.c:2136
 cont_write_begin+0x430/0x770 fs/buffer.c:2486
 fat_write_begin+0x8d/0x120 fs/fat/inode.c:222
 generic_perform_write+0x1f8/0x480 mm/filemap.c:3047
 __generic_file_write_iter+0x239/0x5b0 mm/filemap.c:3172
 generic_file_write_iter+0x303/0x660 mm/filemap.c:3200
 call_write_iter include/linux/fs.h:1777 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x4a7/0x6b0 fs/read_write.c:482
 vfs_write+0x198/0x500 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xfd/0x230 fs/read_write.c:582
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a639
RSP: 002b:00007f5eddc72c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a639
RDX: 00000000fffffe8b RSI: 0000000020000100 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5eddc736d4
R13: 00000000004caf1e R14: 00000000004e33c8 R15: 00000000ffffffff
Code: fa 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 4d 4c 89 63 58 4c 89 ef e8 e0 2a 83 04 e9 13 fe ff ff e8 c6 63 c3 ff <0f> 0b 4c 89 ff e8 dc 16 ed ff e9 f8 fd ff ff e8 d2 16 ed ff e9 
RIP: mark_buffer_dirty_inode fs/buffer.c:605 [inline] RSP: ffff88804ef37528
RIP: mark_buffer_dirty_inode+0x2ea/0x3e0 fs/buffer.c:596 RSP: ffff88804ef37528
base_sock_release(ffff88809a13d080) sk=ffff8880a878a8c0
getblk(): invalid block size 512 requested
logical block size: 4096
kobject: 'loop0' (ffff888050bf20e0): kobject_uevent_env
---[ end trace c5d5edb2f5b4b9b2 ]---
kobject: 'loop0' (ffff888050bf20e0): fill_kobj_path: path = '/devices/virtual/block/loop0'
CPU: 0 PID: 7342 Comm: syz-executor.0 Tainted: G      D         4.14.154 #0
kobject: 'loop2' (ffff8880a4a38960): kobject_uevent_env
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x142/0x197 lib/dump_stack.c:58
 __getblk_slow fs/buffer.c:1092 [inline]
 __getblk_gfp.cold+0xc4/0xe5 fs/buffer.c:1383
kobject: 'loop2' (ffff8880a4a38960): fill_kobj_path: path = '/devices/virtual/block/loop2'
 __bread_gfp+0x2e/0x290 fs/buffer.c:1417
 sb_bread include/linux/buffer_head.h:307 [inline]
 fat__get_entry+0x4a3/0x8b0 fs/fat/dir.c:100
base_sock_release(ffff8880940d7940) sk=ffff8880a1e1cac0
 fat_get_entry fs/fat/dir.c:128 [inline]
 fat_search_long+0x233/0x1190 fs/fat/dir.c:477