syzbot


general protection fault in ext4_finish_bio (2)

Status: moderation: reported on 2025/03/27 03:26
Subsystems: ext4
[Documentation on labels]
Reported-by: syzbot+870cc86b992df3721856@syzkaller.appspotmail.com
First crash: 7d22h, last: 7d22h
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in ext4_finish_bio ext4 C done 1 640d 636d 23/28 fixed on 2023/10/12 12:48

Sample crash report:
Buffer I/O error on device loop5, logical block 371
Buffer I/O error on device loop5, logical block 371
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 UID: 0 PID: 53 Comm: kworker/u8:3 Not tainted 6.14.0-rc7-syzkaller-00202-g183601b78a9b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
RIP: 0010:ext4_finish_bio+0x262/0xc60 fs/ext4/page-io.c:120
Code: ff 85 db 4c 89 74 24 28 74 50 0f b6 fb e8 46 bf 4c 02 41 89 c4 49 8d 5e 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 60 19 a2 ff 4c 8b 33 31 ff 44 89 e6
RSP: 0018:ffffc90000be7800 EFLAGS: 00010216
RAX: 0000000000000003 RBX: 000000000000001b RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 000000000000000a RDI: 0000000000000013
RBP: ffffc90000be79b8 R08: ffffffff84d3c538 R09: 1ffffd40003d46c0
R10: dffffc0000000000 R11: fffff940003d46c1 R12: 00000000fffffffb
R13: 000000000001b000 R14: 0000000000000003 R15: 1ffff9200017cf23
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200001000000 CR3: 000000007c6dc000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_release_io_end+0xdf/0x2c0 fs/ext4/page-io.c:159
 ext4_end_io_end fs/ext4/page-io.c:193 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:258 [inline]
 ext4_end_io_rsv_work+0x5da/0x6f0 fs/ext4/page-io.c:272
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xac0/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7ab/0x920 kernel/kthread.c:464
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_finish_bio+0x262/0xc60 fs/ext4/page-io.c:120
Code: ff 85 db 4c 89 74 24 28 74 50 0f b6 fb e8 46 bf 4c 02 41 89 c4 49 8d 5e 18 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 60 19 a2 ff 4c 8b 33 31 ff 44 89 e6
RSP: 0018:ffffc90000be7800 EFLAGS: 00010216
RAX: 0000000000000003 RBX: 000000000000001b RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 000000000000000a RDI: 0000000000000013
RBP: ffffc90000be79b8 R08: ffffffff84d3c538 R09: 1ffffd40003d46c0
R10: dffffc0000000000 R11: fffff940003d46c1 R12: 00000000fffffffb
R13: 000000000001b000 R14: 0000000000000003 R15: 1ffff9200017cf23
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200001000000 CR3: 0000000034182000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	ff 85 db 4c 89 74    	incl   0x74894cdb(%rbp)
   6:	24 28                	and    $0x28,%al
   8:	74 50                	je     0x5a
   a:	0f b6 fb             	movzbl %bl,%edi
   d:	e8 46 bf 4c 02       	call   0x24cbf58
  12:	41 89 c4             	mov    %eax,%r12d
  15:	49 8d 5e 18          	lea    0x18(%r14),%rbx
  19:	48 89 d8             	mov    %rbx,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 60 19 a2 ff       	call   0xffa21998
  38:	4c 8b 33             	mov    (%rbx),%r14
  3b:	31 ff                	xor    %edi,%edi
  3d:	44 89 e6             	mov    %r12d,%esi

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/23 03:20 upstream 183601b78a9b c6512ef7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root general protection fault in ext4_finish_bio
* Struck through repros no longer work on HEAD.