syzbot


general protection fault in ext4_commit_super

Status: fixed on 2021/03/10 01:48
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+9043030c040ce1849a60@syzkaller.appspotmail.com
Fix commit: c92dc856848f ext4: defer saving error info from atomic context
First crash: 1187d, last: 1184d
Cause bisection: introduced by (bisect log) :
commit e810c942a325cf749e859d7aa3a43dc219cea299
Author: Jan Kara <jack@suse.cz>
Date: Wed Dec 16 10:18:40 2020 +0000

  ext4: save error info to sb through journal if available

Crash: WARNING: ODEBUG bug in ext4_fill_super (log)
Repro: C syz .config
  
Duplicate bugs (1)
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
WARNING: ODEBUG bug in ext4_fill_super (2) ext4 C done 1094 1105d 1183d 0/26 closed as dup on 2020/12/22 11:33
Discussions (2)
Title Replies (including bot) Last reply
Re: general protection fault in ext4_commit_super 2 (2) 2020/12/22 18:13
general protection fault in ext4_commit_super 0 (1) 2020/12/22 08:54

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.10.0-next-20201218-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events flush_stashed_error_work
RIP: 0010:ext4_commit_super+0x52/0x510 fs/ext4/super.c:5548
Code: 48 c1 ea 03 80 3c 02 00 0f 85 21 04 00 00 48 8b 9d 78 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 60 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f1 03 00 00 48 8b 5b 60 48 85 db 0f 84 13 01 00
RSP: 0018:ffffc90000cc7cb8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000000000c RSI: ffffffff8217a0db RDI: 0000000000000060
RBP: ffff88802441c000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8217a7fa R11: 0000000000000000 R12: ffff88802441c000
R13: ffff88802441c678 R14: ffff8880109a5a00 R15: ffff8880b9c34440
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000400200 CR3: 0000000014038000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 flush_stashed_error_work+0x1c9/0x2a0 fs/ext4/super.c:727
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Modules linked in:
---[ end trace dca7dc492b64f0a6 ]---
RIP: 0010:ext4_commit_super+0x52/0x510 fs/ext4/super.c:5548
Code: 48 c1 ea 03 80 3c 02 00 0f 85 21 04 00 00 48 8b 9d 78 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 60 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f1 03 00 00 48 8b 5b 60 48 85 db 0f 84 13 01 00
RSP: 0018:ffffc90000cc7cb8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000000000c RSI: ffffffff8217a0db RDI: 0000000000000060
RBP: ffff88802441c000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8217a7fa R11: 0000000000000000 R12: ffff88802441c000
R13: ffff88802441c678 R14: ffff8880109a5a00 R15: ffff8880b9c34440
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000400200 CR3: 0000000025563000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/12/18 23:48 linux-next 0d52778b8710 04201c06 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2020/12/18 23:18 linux-next 0d52778b8710 04201c06 .config console log report syz C ci-upstream-linux-next-kasan-gce-root
2020/12/21 08:45 linux-next 4c6ed015c2a5 04201c06 .config console log report info ci-upstream-linux-next-kasan-gce-root
2020/12/18 08:44 linux-next 0d52778b8710 04201c06 .config console log report info ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.