------------[ cut here ]------------
sb_rdonly(sb)
WARNING: fs/ext4/ext4_jbd2.c:75 at ext4_journal_check_start+0x24f/0x2b0 fs/ext4/ext4_jbd2.c:75, CPU#0: kworker/u4:2/30
Modules linked in:
CPU: 0 UID: 0 PID: 30 Comm: kworker/u4:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:ext4_journal_check_start+0x24f/0x2b0 fs/ext4/ext4_jbd2.c:75
Code: 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 a6 92 44 ff 41 bf fb ff ff ff eb e0 e8 99 92 44 ff eb d3 e8 92 92 44 ff 90 <0f> 0b 90 eb c8 e8 87 92 44 ff 90 0f 0b 90 43 80 7c 25 00 00 0f 85
RSP: 0018:ffffc90000386bf0 EFLAGS: 00010293
RAX: ffffffff828131de RBX: ffff8880123a6000 RCX: ffff88801ed4a4c0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000b66 R08: ffff8880123a4417 R09: 1ffff11002474882
R10: dffffc0000000000 R11: ffffed1002474883 R12: dffffc0000000000
R13: 1ffff11002474cc7 R14: ffff8880123a6638 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff88808ca4c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffd7ca3e20 CR3: 000000004244d000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __ext4_journal_start_sb+0x147/0x620 fs/ext4/ext4_jbd2.c:107
 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline]
 ext4_do_writepages+0xf94/0x46e0 fs/ext4/inode.c:2917
 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3029
 do_writepages+0x32e/0x550 mm/page-writeback.c:2554
 __writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1762
 writeback_sb_inodes+0x992/0x1a20 fs/fs-writeback.c:2054
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
 wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241
 wb_check_background_flush fs/fs-writeback.c:2311 [inline]
 wb_do_writeback fs/fs-writeback.c:2399 [inline]
 wb_workfn+0xbf9/0xf50 fs/fs-writeback.c:2426
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>