------------[ cut here ]------------
Trying to write to read-only block-device nullb0 (partno 0)
WARNING: CPU: 0 PID: 8534 at block/blk-core.c:857 bio_check_ro block/blk-core.c:857 [inline]
WARNING: CPU: 0 PID: 8534 at block/blk-core.c:857 submit_bio_checks+0x1aba/0x1f70 block/blk-core.c:985
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8534 Comm: kworker/u4:5 Not tainted 5.8.0-rc3-next-20200703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-250:0)
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:231
 __warn.cold+0x20/0x45 kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:235
 exc_invalid_op+0x13/0x40 arch/x86/kernel/traps.c:255
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:563
RIP: 0010:bio_check_ro block/blk-core.c:857 [inline]
RIP: 0010:submit_bio_checks+0x1aba/0x1f70 block/blk-core.c:985
Code: 04 00 00 45 8b a4 24 a4 05 00 00 48 8d 74 24 68 48 89 ef e8 b8 21 fe ff 48 c7 c7 e0 ce 91 88 48 89 c6 44 89 e2 e8 08 df c0 fd <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02
RSP: 0018:ffffc90001087070 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff8880a1378240 RCX: 0000000000000000
RDX: ffff88804ff50180 RSI: ffffffff815d7d27 RDI: fffff52000210e00
RBP: ffff8880472806c0 R08: 0000000000000001 R09: ffff8880ae6318e7
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8880472806c8 R14: 0000000000000000 R15: ffff8880472806e8
 submit_bio_noacct+0x89/0x12d0 block/blk-core.c:1198
 submit_bio+0x263/0x5b0 block/blk-core.c:1283
 submit_bh_wbc+0x685/0x8e0 fs/buffer.c:3105
 __block_write_full_page+0x837/0x12e0 fs/buffer.c:1848
 block_write_full_page+0x214/0x270 fs/buffer.c:3034
 __writepage+0x60/0x170 mm/page-writeback.c:2311
 write_cache_pages+0x736/0x11b0 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
 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
 __writeback_inodes_wb+0xc6/0x280 fs/fs-writeback.c:1790
 wb_writeback+0x8bb/0xd40 fs/fs-writeback.c:1896
 wb_check_start_all fs/fs-writeback.c:2020 [inline]
 wb_do_writeback fs/fs-writeback.c:2046 [inline]
 wb_workfn+0xc50/0x13e0 fs/fs-writeback.c:2080
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Kernel Offset: disabled
Rebooting in 86400 seconds..