syzbot


general protection fault in do_unlinkat

Status: premoderation: reported C repro on 2025/07/15 16:32
Bug presence: origin:downstream
[Documentation on labels]
Reported-by: syzbot+182816dea312c849adc5@syzkaller.appspotmail.com
First crash: 20d, last: 2d22h
Bug presence (3)
Date Name Commit Repro Result
2025/07/15 android16-6.12 (ToT) a11268a7e257 C [report] general protection fault in do_unlinkat
2025/07/15 lts (merge base) e0e2f7824338 C Didn't crash
2025/07/15 upstream (ToT) 155a3c003e55 C Didn't crash
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 general protection fault in do_unlinkat 2 C done 43 2d23h 765d 0/2 upstream: reported C repro on 2023/07/01 21:31
android-5-15 general protection fault in do_unlinkat origin:downstream 2 C done 10 2d11h 765d 0/2 upstream: reported C repro on 2023/07/01 22:19
android-6-1 general protection fault in do_unlinkat origin:downstream 2 C done 7 9d01h 765d 0/2 upstream: reported C repro on 2023/07/01 22:19
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/07/30 13:59 10m retest repro android16-6.12 report log

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 297 Comm: syz-executor179 Not tainted 6.12.38-syzkaller-gbf0fb8bb181b #0 d02c7cfa86e34ad1734bbfdc1f5f1c3ce9be47fc
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__d_entry_type include/linux/dcache.h:415 [inline]
RIP: 0010:d_is_miss include/linux/dcache.h:420 [inline]
RIP: 0010:d_is_negative include/linux/dcache.h:466 [inline]
RIP: 0010:do_unlinkat+0x27e/0x5a0 fs/namei.c:4526
Code: e8 f7 67 9b ff 31 db 41 81 ff 00 00 20 00 0f 95 c3 83 c3 eb e9 d7 00 00 00 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 37 02 00 00 41 8b 1e be 00 00 70 00 21 de
RSP: 0018:ffffc900011cfe00 EFLAGS: 00010203
RAX: 0000000000000001 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88812c4a9300 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900011cfee0 R08: ffff8881f6e50a07 R09: 1ffff1103edca140
R10: dffffc0000000000 R11: ffffed103edca141 R12: 1ffff1102223fe8e
R13: ffff8881111ff470 R14: 000000000000000d R15: 0000000000000000
FS:  00007f4728f606c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000a000 CR3: 0000000130484000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 __do_sys_unlinkat fs/namei.c:4576 [inline]
 __se_sys_unlinkat fs/namei.c:4569 [inline]
 __x64_sys_unlinkat+0xda/0xf0 fs/namei.c:4569
 x64_sys_call+0x2974/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:264
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f4728fb2539
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4728f60218 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 00007f472903f3e8 RCX: 00007f4728fb2539
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 00000000ffffff9c
RBP: 00007f472903f3e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f472900c03c
R13: 0000200000008280 R14: 00007f472900a016 R15: 00002000000020c0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__d_entry_type include/linux/dcache.h:415 [inline]
RIP: 0010:d_is_miss include/linux/dcache.h:420 [inline]
RIP: 0010:d_is_negative include/linux/dcache.h:466 [inline]
RIP: 0010:do_unlinkat+0x27e/0x5a0 fs/namei.c:4526
Code: e8 f7 67 9b ff 31 db 41 81 ff 00 00 20 00 0f 95 c3 83 c3 eb e9 d7 00 00 00 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <0f> b6 04 08 84 c0 0f 85 37 02 00 00 41 8b 1e be 00 00 70 00 21 de
RSP: 0018:ffffc900011cfe00 EFLAGS: 00010203
RAX: 0000000000000001 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: ffff88812c4a9300 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900011cfee0 R08: ffff8881f6e50a07 R09: 1ffff1103edca140
R10: dffffc0000000000 R11: ffffed103edca141 R12: 1ffff1102223fe8e
R13: ffff8881111ff470 R14: 000000000000000d R15: 0000000000000000
FS:  00007f4728f606c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000a000 CR3: 0000000130484000 CR4: 00000000003526b0
----------------
Code disassembly (best guess):
   0:	e8 f7 67 9b ff       	call   0xff9b67fc
   5:	31 db                	xor    %ebx,%ebx
   7:	41 81 ff 00 00 20 00 	cmp    $0x200000,%r15d
   e:	0f 95 c3             	setne  %bl
  11:	83 c3 eb             	add    $0xffffffeb,%ebx
  14:	e9 d7 00 00 00       	jmp    0xf0
  19:	4c 89 f0             	mov    %r14,%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:	0f b6 04 08          	movzbl (%rax,%rcx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 37 02 00 00    	jne    0x26d
  36:	41 8b 1e             	mov    (%r14),%ebx
  39:	be 00 00 70 00       	mov    $0x700000,%esi
  3e:	21 de                	and    %ebx,%esi

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/02 17:08 android16-6.12 bf0fb8bb181b 7368264b .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in do_unlinkat
2025/07/15 18:08 android16-6.12 2bd1f3631412 03fcfc4b .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in do_unlinkat
2025/07/15 17:21 android16-6.12 2bd1f3631412 03fcfc4b .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in do_unlinkat
2025/07/15 16:31 android16-6.12 2bd1f3631412 03fcfc4b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust general protection fault in do_unlinkat
* Struck through repros no longer work on HEAD.