------------[ cut here ]------------
Trying to write to read-only block-device nullb0 (partno 0)
WARNING: CPU: 1 PID: 6598 at block/blk-core.c:701 bio_check_ro block/blk-core.c:701 [inline]
WARNING: CPU: 1 PID: 6598 at block/blk-core.c:701 submit_bio_checks+0x160c/0x1a80 block/blk-core.c:814
Modules linked in:
CPU: 0 PID: 6598 Comm: syz-executor668 Not tainted 5.14.0-rc3-next-20210730-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bio_check_ro block/blk-core.c:701 [inline]
RIP: 0010:submit_bio_checks+0x160c/0x1a80 block/blk-core.c:814
Code: 00 00 45 0f b6 a4 24 58 05 00 00 48 8d 74 24 60 48 89 ef e8 b6 4a fe ff 48 c7 c7 80 e2 e1 89 48 89 c6 44 89 e2 e8 f2 5d 2c 05 <0f> 0b e9 86 f3 ff ff e8 e8 f4 b6 fd e8 d3 ec 6e 05 31 ff 89 c3 89
RSP: 0018:ffffc90002e2f408 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff88801bb4d5e0 RCX: 0000000000000000
RDX: ffff8880745b0000 RSI: ffffffff815d8978 RDI: fffff520005c5e73
RBP: ffff888019d20500 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815d271e R11: 0000000000000000 R12: 0000000000000000
R13: ffff888019d20510 R14: ffff88801759e780 R15: ffff88801bb4db54
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2970fc7740 CR3: 000000000b68e000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 submit_bio_noacct+0x81/0xf20 block/blk-core.c:1029
 submit_bio+0x1ea/0x470 block/blk-core.c:1106
 submit_bh_wbc+0x5eb/0x7f0 fs/buffer.c:3087
 __block_write_full_page+0x877/0x1360 fs/buffer.c:1842
 block_write_full_page+0x14d/0x190 fs/buffer.c:3013
 __writepage+0x60/0x180 mm/page-writeback.c:2315
 write_cache_pages+0x763/0x11a0 mm/page-writeback.c:2250
 generic_writepages mm/page-writeback.c:2341 [inline]
 generic_writepages+0xe2/0x150 mm/page-writeback.c:2330
 do_writepages+0x1ab/0x770 mm/page-writeback.c:2359
 filemap_fdatawrite_wbc mm/filemap.c:408 [inline]
 filemap_fdatawrite_wbc+0x1d2/0x2b0 mm/filemap.c:398
 __filemap_fdatawrite_range mm/filemap.c:441 [inline]
 filemap_write_and_wait_range mm/filemap.c:712 [inline]
 filemap_write_and_wait_range+0xe1/0x1a0 mm/filemap.c:706
 filemap_write_and_wait include/linux/fs.h:2937 [inline]
 __sync_blockdev fs/block_dev.c:526 [inline]
 sync_blockdev fs/block_dev.c:535 [inline]
 blkdev_put+0x753/0x9e0 fs/block_dev.c:1497
 blkdev_close+0x8c/0xb0 fs/block_dev.c:1551
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbd4/0x2a60 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43da59
Code: Unable to access opcode bytes at RIP 0x43da2f.
RSP: 002b:00007ffc4966f348 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004ae230 RCX: 000000000043da59
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 00000000004ae230
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001