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: 197d, last: 6m
▶ ▼ ✨ 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 (23)
Title Replies (including bot) Last reply
[PATCH v8 2/2] block: wait for inflight requests in bdev_release() 1 (1) 2026/10/18 15:26
[PATCH] loop: Detect write requests that failed to wait for completion. 4 (4) 2026/10/12 08:26
[PATCH v6] loop: Wait for I/O completion in __loop_clr_fd() 1 (1) 2026/10/05 21:06
[PATCH v5 2/2] loop: Perform __loop_clr_fd() from post_release callback. 1 (1) 2026/09/23 05:10
[PATCH v4 2/2] loop: Perform __loop_clr_fd() from run_todo callback. 1 (1) 2026/09/19 10:51
[PATCH v3 2/2] loop: Perform __loop_clr_fd() after disk->open_mutex is dropped. 1 (1) 2026/09/18 15:00
[PATCH v2.1 2/2] loop: Perform __loop_clr_fd() after disk->open_mutex is dropped. 1 (1) 2026/09/18 12:20
[PATCH 2/2] loop: Perform __loop_clr_fd() after disk->open_mutex is dropped. 1 (1) 2026/09/09 10:49
[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 543d 551d 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: 0 UID: 0 PID: 286 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: loop5 loop_workfn
RIP: 0010:file_inode include/linux/fs.h:1348 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2792 [inline]
RIP: 0010:lo_rw_aio+0xc26/0x1100 drivers/block/loop.c:398
Code: e8 8f ca 03 fc 85 db 0f 84 d8 00 00 00 48 8b 44 24 68 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 12 48 89 df e8 ac 58 76 fc 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc90004507620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004507790 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004e16c55 R12: 0000000000000000
R13: 0000000000001000 R14: 0000000000000000 R15: ffff8880270b62b0
FS:  0000000000000000(0000) GS:ffff888124727000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa999ff3000 CR3: 000000005fae0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 do_req_filebacked drivers/block/loop.c:430 [inline]
 loop_handle_cmd drivers/block/loop.c:1845 [inline]
 loop_process_work+0x638/0x11d0 drivers/block/loop.c:1880
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 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:2792 [inline]
RIP: 0010:lo_rw_aio+0xc26/0x1100 drivers/block/loop.c:398
Code: e8 8f ca 03 fc 85 db 0f 84 d8 00 00 00 48 8b 44 24 68 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 12 48 89 df e8 ac 58 76 fc 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc90004507620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004507790 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004e16c55 R12: 0000000000000000
R13: 0000000000001000 R14: 0000000000000000 R15: ffff8880270b62b0
FS:  0000000000000000(0000) GS:ffff888124727000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f381aebb000 CR3: 000000002fd7e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	e8 8f ca 03 fc       	call   0xfc03ca94
   5:	85 db                	test   %ebx,%ebx
   7:	0f 84 d8 00 00 00    	je     0xe5
   d:	48 8b 44 24 68       	mov    0x68(%rsp),%rax
  12:	48 8d 98 a0 00 00 00 	lea    0xa0(%rax),%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 12                	je     0x42
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 ac 58 76 fc       	call   0xfc7658e4
  38:	48                   	rex.W
  39:	b9 00 00 00 00       	mov    $0x0,%ecx
  3e:	00 fc                	add    %bh,%ah

Crashes (4194):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/28 12:10 upstream 65ba8f34ec88 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 11:06 upstream 65ba8f34ec88 858db2ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 08:46 upstream 65ba8f34ec88 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 06:25 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 05:10 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 03:56 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 02:39 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 01:31 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/28 00:23 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 22:41 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 21:31 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 20:08 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 19:37 upstream 62c457528529 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 18:05 upstream d135ab453a74 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 16:40 upstream d135ab453a74 96923c60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 15:29 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 14:05 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 12:17 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 10:56 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 09:40 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 07:00 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 06:34 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 03:50 upstream d135ab453a74 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 01:35 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/27 00:25 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 21:07 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 18:18 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 16:28 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 15:28 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 14:54 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 13:48 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 10:52 upstream 7d37252fc49a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 09:04 upstream 7d37252fc49a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 07:56 upstream 7d37252fc49a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 06:04 upstream 7d37252fc49a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 05:06 upstream 7d37252fc49a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 03:10 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/26 00:17 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 18:58 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 17:39 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 16:27 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 15:23 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 13:47 upstream 6fba331225f5 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 12:40 upstream 6fba331225f5 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 10:41 upstream 6fba331225f5 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 08:47 upstream 6fba331225f5 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/25 06:39 upstream 6fba331225f5 1d9ca40b .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.