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: 107d, last: 42m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
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 (12)
Title Replies (including bot) Last reply
[PATCH v5] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/07/16 00:05
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 v3] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/05/25 03:40
[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 453d 461d 29/29 fixed on 2025/07/08 00:33

Sample crash report:
Oops: general protection [  362.253319][   T66] 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: 66 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: loop3 loop_workfn
RIP: 0010:file_inode include/linux/fs.h:1348 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2765 [inline]
RIP: 0010:lo_rw_aio+0xa9f/0xf30 drivers/block/loop.c:397
Code: 89 33 31 ff 8b 5c 24 34 89 de e8 bc 99 1c 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 b2 07 86 fc 4c 89 7c 24 20 48 8b
RSP: 0018:ffffc9000151f640 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff88801bb2be00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000151f7b0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004d900e5 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888026c80730
FS:  0000000000000000(0000) GS:ffff888125c41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558bf8aa68 CR3: 00000000374d2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 do_req_filebacked drivers/block/loop.c:429 [inline]
 loop_handle_cmd drivers/block/loop.c:1917 [inline]
 loop_process_work+0x638/0x11d0 drivers/block/loop.c:1952
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 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:2765 [inline]
RIP: 0010:lo_rw_aio+0xa9f/0xf30 drivers/block/loop.c:397
Code: 89 33 31 ff 8b 5c 24 34 89 de e8 bc 99 1c 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 b2 07 86 fc 4c 89 7c 24 20 48 8b
RSP: 0018:ffffc9000151f640 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: ffff88801bb2be00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000151f7b0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004d900e5 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888026c80730
FS:  0000000000000000(0000) GS:ffff888125c41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558bf8aa68 CR3: 000000001237c000 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 bc 99 1c fc       	call   0xfc1c99cb
   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 b2 07 86 fc       	call   0xfc8607eb
  39:	4c 89 7c 24 20       	mov    %r15,0x20(%rsp)
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b

Crashes (1792):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/30 03:19 upstream fc46aed51f62 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/30 00:56 upstream fc46aed51f62 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 23:34 upstream fc02acf6ac0c 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 21:39 upstream fc02acf6ac0c 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 18:04 upstream fc02acf6ac0c 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 15:38 upstream fc02acf6ac0c 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 14:38 upstream fc02acf6ac0c 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 10:12 upstream fc02acf6ac0c 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 08:24 upstream fc02acf6ac0c 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 07:20 upstream fc02acf6ac0c 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 06:01 upstream fc02acf6ac0c 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/29 03:56 upstream fc02acf6ac0c 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 23:07 upstream 3b5f4b83c4ab edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 21:43 upstream 3b5f4b83c4ab edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 20:11 upstream 3b5f4b83c4ab edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 19:25 upstream 3b5f4b83c4ab edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 17:16 upstream 62cc90241548 edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 14:44 upstream 62cc90241548 edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 13:40 upstream 62cc90241548 edc8a875 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 11:38 upstream 62cc90241548 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 09:19 upstream 62cc90241548 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 07:36 upstream 62cc90241548 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 02:45 upstream 62cc90241548 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/28 01:35 upstream 62cc90241548 45ae1df4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 22:39 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 21:30 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 20:25 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 18:03 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 16:47 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 14:53 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 13:49 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 12:37 upstream f5098b6bae76 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 11:10 upstream f5098b6bae76 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 05:49 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 03:48 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 03:29 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 02:11 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/27 00:10 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/26 22:11 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/26 21:10 upstream 4235cb24ec1e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/26 19:11 upstream 3dab139d4795 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/26 17:37 upstream 3dab139d4795 492bab15 .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.