syzbot


general protection fault in lo_ioctl

Status: premoderation: reported on 2025/06/26 01:08
Reported-by: syzbot+ef7afc17e20b4010f350@syzkaller.appspotmail.com
First crash: 3d03h, last: 3d03h
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 general protection fault in lo_ioctl 13 2562d 2894d 0/3 closed as invalid on 2019/01/01 20:10
upstream general protection fault in lo_ioctl 17 2800d 2794d 0/29 closed as invalid on 2018/02/12 16:15
android-44 general protection fault in lo_ioctl 1 2571d 2571d 0/2 auto-closed as invalid on 2019/02/22 15:09
upstream general protection fault in lo_ioctl (2) block syz 2 2615d 2614d 11/29 fixed on 2019/01/15 20:25
android-54 KASAN: use-after-free Read in lo_ioctl 1 895d 895d 0/2 auto-obsoleted due to no activity on 2023/05/15 06:29

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
CPU: 1 PID: 10022 Comm: udevd Tainted: G        W         5.10.238-syzkaller-00008-g59e9a7228857 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:lo_simple_ioctl drivers/block/loop.c:1664 [inline]
RIP: 0010:lo_ioctl+0x960/0x1a80 drivers/block/loop.c:1726
Code: de e8 c4 f4 af fe 49 39 dc 0f 85 b2 06 00 00 e8 a6 f2 af fe 45 31 e4 e9 a7 08 00 00 49 8d 9f e8 00 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e1 e2 e9 fe 48 8b 1b 48 85 db 0f
RSP: 0018:ffffc90000fa7340 EFLAGS: 00010206
RAX: 000000000000001d RBX: 00000000000000e8 RCX: 0000000000000005
RDX: ffffffff82b39c06 RSI: ffffffff86633990 RDI: 00000000800870ec
RBP: ffffc90000fa7db0 R08: ffff888115c7a780 R09: 0000000000000003
R10: 0000000000004c09 R11: 0000000000000000 R12: dffffc0000000000
R13: 00000000800870ec R14: ffff88810919c440 R15: 0000000000000000
FS:  00007f82f94e5880(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f48a0c145e1 CR3: 0000000111c98000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __blkdev_driver_ioctl block/ioctl.c:240 [inline]
 blkdev_ioctl+0x2d2/0x5b0 block/ioctl.c:635
 block_ioctl+0xae/0x100 fs/block_dev.c:1888
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:739
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f82f9649378
Code: 00 00 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 07 89 d0 c3 0f 1f 40 00 48 8b 15 49 3a 0d
RSP: 002b:00007ffc4171acd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000200 RCX: 00007f82f9649378
RDX: 00007ffc4171acf0 RSI: 00000000800870ec RDI: 0000000000000009
RBP: 000055f84de6dd50 R08: 0000000000000030 R09: ffffffffffffffff
R10: 000055f84de6ddb0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 000055f84de6fc48 R15: 00007f82f9d2939c
Modules linked in:
---[ end trace a10b853bc85d220c ]---
RIP: 0010:lo_simple_ioctl drivers/block/loop.c:1664 [inline]
RIP: 0010:lo_ioctl+0x960/0x1a80 drivers/block/loop.c:1726
Code: de e8 c4 f4 af fe 49 39 dc 0f 85 b2 06 00 00 e8 a6 f2 af fe 45 31 e4 e9 a7 08 00 00 49 8d 9f e8 00 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e1 e2 e9 fe 48 8b 1b 48 85 db 0f
RSP: 0018:ffffc90000fa7340 EFLAGS: 00010206
RAX: 000000000000001d RBX: 00000000000000e8 RCX: 0000000000000005
RDX: ffffffff82b39c06 RSI: ffffffff86633990 RDI: 00000000800870ec
RBP: ffffc90000fa7db0 R08: ffff888115c7a780 R09: 0000000000000003
R10: 0000000000004c09 R11: 0000000000000000 R12: dffffc0000000000
R13: 00000000800870ec R14: ffff88810919c440 R15: 0000000000000000
FS:  00007f82f94e5880(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2eb18b CR3: 0000000111c98000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	e8 c4 f4 af fe       	call   0xfeaff4c9
   5:	49 39 dc             	cmp    %rbx,%r12
   8:	0f 85 b2 06 00 00    	jne    0x6c0
   e:	e8 a6 f2 af fe       	call   0xfeaff2b9
  13:	45 31 e4             	xor    %r12d,%r12d
  16:	e9 a7 08 00 00       	jmp    0x8c2
  1b:	49 8d 9f e8 00 00 00 	lea    0xe8(%r15),%rbx
  22:	48 89 d8             	mov    %rbx,%rax
  25:	48 c1 e8 03          	shr    $0x3,%rax
* 29:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 e1 e2 e9 fe       	call   0xfee9e319
  38:	48 8b 1b             	mov    (%rbx),%rbx
  3b:	48 85 db             	test   %rbx,%rbx
  3e:	0f                   	.byte 0xf

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/26 01:07 android13-5.10-lts 59e9a7228857 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in lo_ioctl
* Struck through repros no longer work on HEAD.