general protection fault in lo_rw_aio

Status: upstream: reported on 2026/04/18 00:02
Subsystems: block
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+cd8a9a308e879a4e2c28@syzkaller.appspotmail.com
First crash: 147d, last: 44m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
c6adaab8 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in lo_rw_aio 2026/05/23 13:03 2026/05/23 13:03 2026/05/23 14:13 c69befb3
Discussions (15)
Title Replies (including bot) Last reply
[PATCH v7.1] loop: Fix NULL pointer dereference in lo_rw_aio() 3 (3) 2026/09/04 01:07
[PATCH v7] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/08/28 15:53
[PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() 2 (2) 2026/08/28 15:01
[PATCH v5] loop: Fix NULL pointer dereference in lo_rw_aio() 2 (2) 2026/08/23 11:17
[syzbot] Monthly block report (Aug 2026) 0 (1) 2026/08/05 20:32
Re: [linux-next:master] [loop] d908729e74: stress-ng.umount.ops_per_sec 100.0% regression 3 (3) 2026/07/15 16:02
[syzbot] [block?] general protection fault in lo_rw_aio 2 (4) 2026/07/15 16:02
[syzbot] Monthly block report (Jul 2026) 0 (1) 2026/07/05 12:32
[PATCH v4] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/06/07 10:54
Re: [PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() 6 (6) 2026/06/02 02:02
[PATCH] block: assign caller-specific lockdep class to disk->open_mutex 2 (2) 2026/05/30 22:50
[PATCH] loop: reject binding to procfs and sysfs files 1 (1) 2026/05/30 13:48
[PATCH] loop: add sync_blockdev() in __loop_clr_fd() to prevent UAF 7 (7) 2026/05/22 11:50
[PATCH v2] loop: Fix NULL pointer dereference by synchronizing lo_release and loop_queue_rq 1 (1) 2026/05/15 01:38
[PATCH] loop: Fix NULL pointer dereference by synchronizing lo_release and loop_queue_rq 1 (1) 2026/05/11 11:43
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: unable to handle kernel NULL pointer dereference in lo_rw_aio block 10 syz, C 10 493d 501d 29/29 fixed on 2025/07/08 00:33

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000014: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000000a0-0x00000000000000a7]
CPU: 1 UID: 0 PID: 1378 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: loop2 loop_workfn
RIP: 0010:file_inode include/linux/fs.h:1348 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2785 [inline]
RIP: 0010:lo_rw_aio+0xa9f/0xf30 drivers/block/loop.c:398
Code: 89 33 31 ff 8b 5c 24 34 89 de e8 5c 74 13 fc 85 db 0f 84 cb 00 00 00 48 8b 44 24 58 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 a2 55 7f fc 4c 89 7c 24 20 48 8b
RSP: 0018:ffffc900070df620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff88802a25be80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900070df790 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004d93315 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888026c998b0
FS:  0000000000000000(0000) GS:ffff888125cd1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555616c8a68 CR3: 00000000509e4000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 do_req_filebacked drivers/block/loop.c:430 [inline]
 loop_handle_cmd drivers/block/loop.c:1949 [inline]
 loop_process_work+0x638/0x11d0 drivers/block/loop.c:1984
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:file_inode include/linux/fs.h:1348 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2785 [inline]
RIP: 0010:lo_rw_aio+0xa9f/0xf30 drivers/block/loop.c:398
Code: 89 33 31 ff 8b 5c 24 34 89 de e8 5c 74 13 fc 85 db 0f 84 cb 00 00 00 48 8b 44 24 58 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 a2 55 7f fc 4c 89 7c 24 20 48 8b
RSP: 0018:ffffc900070df620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff88802a25be80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900070df790 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004d93315 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888026c998b0
FS:  0000000000000000(0000) GS:ffff888125cd1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f761a2dda08 CR3: 0000000055026000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	89 33                	mov    %esi,(%rbx)
   2:	31 ff                	xor    %edi,%edi
   4:	8b 5c 24 34          	mov    0x34(%rsp),%ebx
   8:	89 de                	mov    %ebx,%esi
   a:	e8 5c 74 13 fc       	call   0xfc13746b
   f:	85 db                	test   %ebx,%ebx
  11:	0f 84 cb 00 00 00    	je     0xe2
  17:	48 8b 44 24 58       	mov    0x58(%rsp),%rax
  1c:	48 8d 98 a0 00 00 00 	lea    0xa0(%rax),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 a2 55 7f fc       	call   0xfc7f55db
  39:	4c 89 7c 24 20       	mov    %r15,0x20(%rsp)
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b

Crashes (2490):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/08 12:34 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/08 09:32 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/08 08:23 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/08 07:21 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/08 05:23 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/08 04:22 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/08 02:45 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 23:23 upstream df2908090cda 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 21:24 upstream df2908090cda 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 15:52 upstream df2908090cda 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 14:49 upstream df2908090cda 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 13:14 upstream df2908090cda 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 10:42 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 08:09 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 06:39 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/07 00:11 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 21:35 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 20:29 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 19:05 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 18:47 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 17:38 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 16:09 upstream 9f0346dcbea3 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 14:28 upstream 9f0346dcbea3 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 11:19 upstream 9f0346dcbea3 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 07:37 upstream 9f0346dcbea3 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 06:20 upstream 9f0346dcbea3 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 04:55 upstream 9f0346dcbea3 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 03:45 upstream 9f0346dcbea3 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/06 00:20 upstream 4d7d9486c04d 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 21:53 upstream 4d7d9486c04d 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 20:44 upstream 4d7d9486c04d 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 19:30 upstream 4d7d9486c04d 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 18:08 upstream 4d7d9486c04d 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 15:56 upstream 4d7d9486c04d 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 14:21 upstream 4d7d9486c04d 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 12:28 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 10:04 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 04:27 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 02:10 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 01:10 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/05 00:39 upstream 654ae5d73c05 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/04 22:02 upstream bc35965f6940 f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/04 19:55 upstream bc35965f6940 f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/04 14:52 upstream bc35965f6940 f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/04 12:17 upstream bc35965f6940 f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/04 11:16 upstream bc35965f6940 f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/09/04 05:19 upstream 8ab1afb2eb24 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/05/22 22:16 upstream 45255ea1ca09 5f091fcc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/04/17 21:49 upstream 43cfbdda5af6 24ecfc1e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/02 08:16 linux-next 7de6ae9e1220 27192279 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in lo_rw_aio
2026/04/13 23:56 linux-next 1c7cc4904160 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in lo_rw_aio
* Struck through repros no longer work on HEAD.