------------[ cut here ]------------
Trying to write to read-only block-device nullb0 (partno 0)
WARNING: CPU: 0 PID: 8442 at block/blk-core.c:704 bio_check_ro block/blk-core.c:704 [inline]
WARNING: CPU: 0 PID: 8442 at block/blk-core.c:704 submit_bio_checks+0x165c/0x1aa0 block/blk-core.c:817
Modules linked in:
CPU: 0 PID: 8442 Comm: syz-executor945 Not tainted 5.12.0-next-20210504-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:704 [inline]
RIP: 0010:submit_bio_checks+0x165c/0x1aa0 block/blk-core.c:817
Code: 00 00 45 0f b6 a4 24 e0 05 00 00 48 8d 74 24 60 48 89 ef e8 16 36 fe ff 48 c7 c7 60 e5 c0 89 48 89 c6 44 89 e2 e8 b7 b0 1b 05 <0f> 0b e9 36 f3 ff ff e8 e8 e3 bb fd 0f 0b e9 bf f1 ff ff e8 dc e3
RSP: 0018:ffffc90000f0f318 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8881461e4560 RCX: 0000000000000000
RDX: ffff888024560000 RSI: ffffffff815cc9f5 RDI: fffff520001e1e55
RBP: ffff888015bee280 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815c685e R11: 0000000000000000 R12: 0000000000000000
R13: ffff888015bee290 R14: ffff88801e4ce780 R15: ffff8881461e4a64
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe25a5b7000 CR3: 000000002fa1b000 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:1032
 submit_bio+0x263/0x5e0 block/blk-core.c:1118
 submit_bh_wbc+0x5eb/0x7f0 fs/buffer.c:3112
 __block_write_full_page+0x86c/0x1340 fs/buffer.c:1867
 block_write_full_page+0x14d/0x190 fs/buffer.c:3038
 __writepage+0x60/0x180 mm/page-writeback.c:2311
 write_cache_pages+0x759/0x11a0 mm/page-writeback.c:2246
 generic_writepages mm/page-writeback.c:2337 [inline]
 generic_writepages+0xe2/0x150 mm/page-writeback.c:2326
 do_writepages+0xec/0x290 mm/page-writeback.c:2352
 __filemap_fdatawrite_range+0x2a5/0x390 mm/filemap.c:413
 filemap_write_and_wait_range mm/filemap.c:686 [inline]
 filemap_write_and_wait_range+0x65/0x100 mm/filemap.c:680
 filemap_write_and_wait include/linux/fs.h:2892 [inline]
 __sync_blockdev fs/block_dev.c:526 [inline]
 sync_blockdev fs/block_dev.c:535 [inline]
 __blkdev_put+0x64b/0x790 fs/block_dev.c:1569
 blkdev_put+0x92/0x580 fs/block_dev.c:1638
 blkdev_close+0x8c/0xb0 fs/block_dev.c:1646
 __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+0xbfc/0x2a60 kernel/exit.c:826
 do_group_exit+0x125/0x310 kernel/exit.c:923
 __do_sys_exit_group kernel/exit.c:934 [inline]
 __se_sys_exit_group kernel/exit.c:932 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:932
 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43da99
Code: Unable to access opcode bytes at RIP 0x43da6f.
RSP: 002b:00007ffd5c98c048 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004ae230 RCX: 000000000043da99
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000400488
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ae230
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001