syzbot


general protection fault in __loop_clr_fd

Status: premoderation: reported on 2025/05/06 15:40
Reported-by: syzbot+98b204004d7d547d7db7@syzkaller.appspotmail.com
First crash: 75d, last: 75d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in __loop_clr_fd block 2 C done 5702 1934d 1961d 20/29 fixed on 2022/05/19 12:02

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
CPU: 0 PID: 23939 Comm: syz-executor Tainted: G        W         5.10.236-syzkaller-00012-gab07aeb2c93d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:kobject_uevent_env+0xb5/0x700 lib/kobject_uevent.c:497
Code: 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 29 06 00 00 41 80 0e 08 eb 05 e8 7a 6f 0d ff 4d 89 ec 4d 8d 74 24 20 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 fd 55 47 ff 4d 8b 36 4d 85 f6 75 2d
RSP: 0018:ffffc90000e0f210 EFLAGS: 00010206
RAX: 0000000000000011 RBX: dffffc0000000000 RCX: ffff888117128000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: ffffc90000e0f288 R08: 0000000000000004 R09: 0000000000000003
R10: fffff520001c1e40 R11: 1ffff920001c1e40 R12: 0000000000000068
R13: 0000000000000068 R14: 0000000000000088 R15: 0000000000000002
FS:  000055555f8e2500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f538dfc411b CR3: 0000000134c6a000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 kobject_uevent+0x1d/0x30 lib/kobject_uevent.c:657
 __loop_clr_fd+0x5fc/0x9c0 drivers/block/loop.c:1255
 loop_clr_fd drivers/block/loop.c:1344 [inline]
 lo_ioctl+0xda0/0x1a80 drivers/block/loop.c:1702
 __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: 0033:0x7f677797e56b
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007ffde32503e0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f677797e56b
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
RBP: 00007ffde325047c R08: 000000000000000a R09: 00007ffde3250187
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000a
R13: 000055555f8f5470 R14: 00000000002441a5 R15: 00007ffde32504d0
Modules linked in:
---[ end trace ca02e20567015c8e ]---
RIP: 0010:kobject_uevent_env+0xb5/0x700 lib/kobject_uevent.c:497
Code: 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 29 06 00 00 41 80 0e 08 eb 05 e8 7a 6f 0d ff 4d 89 ec 4d 8d 74 24 20 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 fd 55 47 ff 4d 8b 36 4d 85 f6 75 2d
RSP: 0018:ffffc90000e0f210 EFLAGS: 00010206
RAX: 0000000000000011 RBX: dffffc0000000000 RCX: ffff888117128000
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: ffffc90000e0f288 R08: 0000000000000004 R09: 0000000000000003
R10: fffff520001c1e40 R11: 1ffff920001c1e40 R12: 0000000000000068
R13: 0000000000000068 R14: 0000000000000088 R15: 0000000000000002
FS:  000055555f8e2500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffe8 CR3: 0000000134c6a000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 c1 e8 03          	shr    $0x3,%rax
   4:	0f b6 04 18          	movzbl (%rax,%rbx,1),%eax
   8:	84 c0                	test   %al,%al
   a:	0f 85 29 06 00 00    	jne    0x639
  10:	41 80 0e 08          	orb    $0x8,(%r14)
  14:	eb 05                	jmp    0x1b
  16:	e8 7a 6f 0d ff       	call   0xff0d6f95
  1b:	4d 89 ec             	mov    %r13,%r12
  1e:	4d 8d 74 24 20       	lea    0x20(%r12),%r14
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 f7             	mov    %r14,%rdi
  33:	e8 fd 55 47 ff       	call   0xff475635
  38:	4d 8b 36             	mov    (%r14),%r14
  3b:	4d 85 f6             	test   %r14,%r14
  3e:	75 2d                	jne    0x6d

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/06 15:39 android13-5.10-lts ab07aeb2c93d ae98e6b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 general protection fault in __loop_clr_fd
* Struck through repros no longer work on HEAD.