------------[ cut here ]------------ generic_make_request: Trying to write to read-only block-device nullb0 (partno 0) WARNING: CPU: 0 PID: 21 at block/blk-core.c:797 bio_check_ro block/blk-core.c:797 [inline] WARNING: CPU: 0 PID: 21 at block/blk-core.c:797 generic_make_request_checks+0x1d5c/0x2210 block/blk-core.c:902 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.4.0-rc8 #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:179 [inline] fixup_bug arch/x86/kernel/traps.c:174 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028 RIP: 0010:bio_check_ro block/blk-core.c:797 [inline] RIP: 0010:generic_make_request_checks+0x1d5c/0x2210 block/blk-core.c:902 Code: 00 00 44 8b ab 3c 05 00 00 48 8d b5 78 ff ff ff 4c 89 f7 e8 c6 87 05 00 48 c7 c7 60 18 e5 87 48 89 c6 44 89 ea e8 7c f9 13 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:ffff8880a9a1f020 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff8880a3291000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815cf766 RDI: ffffed1015343df6 RBP: ffff8880a9a1f120 R08: ffff8880a9a0c580 R09: ffffed1015d06159 R10: ffffed1015d06158 R11: ffff8880ae830ac7 R12: ffff8880a7986e08 R13: 0000000000000000 R14: ffff8880a7986e00 R15: ffff8880a32fcef8 generic_make_request+0x8f/0xb50 block/blk-core.c:1018 submit_bio+0x113/0x600 block/blk-core.c:1190 submit_bh_wbc+0x6b6/0x900 fs/buffer.c:3095 __block_write_full_page+0x7fe/0x11b0 fs/buffer.c:1767 block_write_full_page+0x21f/0x270 fs/buffer.c:2953 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:2031 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_old_data_flush fs/fs-writeback.c:1996 [inline] wb_do_writeback fs/fs-writeback.c:2049 [inline] wb_workfn+0xba5/0x1220 fs/fs-writeback.c:2078 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 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..