------------[ cut here ]------------
generic_make_request: Trying to write to read-only block-device nullb0 (partno 0)
WARNING: CPU: 0 PID: 471 at block/blk-core.c:829 bio_check_ro block/blk-core.c:829 [inline]
WARNING: CPU: 0 PID: 471 at block/blk-core.c:829 generic_make_request_checks+0x1c78/0x2190 block/blk-core.c:930
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 471 Comm: kworker/u4:4 Not tainted 5.4.0-rc8-next-20191122-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-251:0)
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x35 kernel/panic.c:582
 report_bug+0x289/0x300 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 fixup_bug arch/x86/kernel/traps.c:169 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:bio_check_ro block/blk-core.c:829 [inline]
RIP: 0010:generic_make_request_checks+0x1c78/0x2190 block/blk-core.c:930
Code: 00 00 44 8b ab 5c 05 00 00 48 8d b5 78 ff ff ff 4c 89 ff e8 aa 91 05 00 48 c7 c7 c0 8f e5 87 48 89 c6 44 89 ea e8 e0 24 11 fe <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 80 3c 02
RSP: 0018:ffff8880a8d67020 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff8880a33c4000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815d88c6 RDI: ffffed10151acdf6
RBP: ffff8880a8d67120 R08: ffff8880a8bf4140 R09: ffffed1015d06621
R10: ffffed1015d06620 R11: ffff8880ae833107 R12: ffff8880a023a408
R13: 0000000000000000 R14: 0000000000000001 R15: ffff8880a023a400
 generic_make_request+0x8f/0xb00 block/blk-core.c:1049
 submit_bio+0x113/0x600 block/blk-core.c:1221
 submit_bh_wbc+0x6b6/0x900 fs/buffer.c:3172
 __block_write_full_page+0x7fe/0x11b0 fs/buffer.c:1844
 block_write_full_page+0x21f/0x270 fs/buffer.c:3030
 blkdev_writepage+0x25/0x30 fs/block_dev.c:609
 __writepage+0x66/0x110 mm/page-writeback.c:2303
 write_cache_pages+0x80c/0x13f0 mm/page-writeback.c:2238
 generic_writepages mm/page-writeback.c:2329 [inline]
 generic_writepages+0xed/0x160 mm/page-writeback.c:2318
 blkdev_writepages+0x1e/0x30 fs/block_dev.c:2060
 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2344
 __writeback_single_inode+0x136/0x1400 fs/fs-writeback.c:1452
 writeback_sb_inodes+0x596/0xf20 fs/fs-writeback.c:1716
 __writeback_inodes_wb+0xc3/0x260 fs/fs-writeback.c:1785
 wb_writeback+0x910/0xd90 fs/fs-writeback.c:1894
 wb_check_background_flush fs/fs-writeback.c:1962 [inline]
 wb_do_writeback fs/fs-writeback.c:2050 [inline]
 wb_workfn+0xa8a/0x1220 fs/fs-writeback.c:2078
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..