syzbot


general protection fault in do_rmdir

Status: upstream: reported C repro on 2023/12/08 13:26
Bug presence: origin:downstream
[Documentation on labels]
Reported-by: syzbot+8f2a09a274a49e1a0dc3@syzkaller.appspotmail.com
First crash: 633d, last: 9d00h
Cause bisection: introduced by (bisect log) :
commit 57f3ff9648991998d008ecf32f2f9e78a08bfb8b
Author: Daniel Rosenberg <drosen@google.com>
Date: Thu Dec 2 21:50:02 2021 +0000

  ANDROID: fuse-bpf v1.1

Crash: BUG: unable to handle kernel NULL pointer dereference in do_rmdir (log)
Repro: C syz .config
  
Bug presence (3)
Date Name Commit Repro Result
2023/12/04 android14-6.1 (ToT) 6465e29536ed C [report] general protection fault in do_rmdir
2023/12/04 lts (merge base) 082280fe94a0 C Didn't crash
2023/12/04 upstream (ToT) 33cc938e65a9 C Didn't crash
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 general protection fault in do_rmdir origin:downstream 2 C 2 43d 43d 0/1 premoderation: reported C repro on 2025/07/16 06:08
android-5-10 general protection fault in do_rmdir 2 C 19 11d 629d 0/2 upstream: reported C repro on 2023/12/08 13:26
android-5-15 general protection fault in do_rmdir origin:downstream 2 C 6 10d 629d 0/2 upstream: reported C repro on 2023/12/08 13:26
Last patch testing requests (10)
Created Duration User Patch Repo Result
2025/08/20 00:35 10m retest repro android14-6.1 report log
2025/08/20 00:35 12m retest repro android14-6.1 report log
2025/08/01 20:00 15m retest repro android14-6.1 report log
2025/07/11 03:37 6m retest repro android14-6.1 report log
2025/06/10 03:37 15m retest repro android14-6.1 report log
2025/05/21 10:30 28m retest repro android14-6.1 report log
2025/05/02 00:58 10m retest repro android14-6.1 report log
2025/03/31 05:41 6m retest repro android14-6.1 report log
2025/03/06 18:49 6m retest repro android14-6.1 report log
2025/01/19 02:37 7m retest repro android14-6.1 report log
Fix bisection attempts (9)
Created Duration User Patch Repo Result
2025/02/20 15:37 1h14m bisect fix android14-6.1 OK (0) job log log
2024/12/15 09:07 1h39m bisect fix android14-6.1 OK (0) job log log
2024/10/19 11:59 1h16m bisect fix android14-6.1 OK (0) job log log
2024/09/17 21:19 57m bisect fix android14-6.1 OK (0) job log log
2024/07/19 18:55 57m bisect fix android14-6.1 OK (0) job log log
2024/05/22 20:59 38m bisect fix android14-6.1 OK (0) job log log
2024/03/14 08:23 1h38m bisect fix android14-6.1 OK (0) job log log
2024/02/10 20:42 48m bisect fix android14-6.1 OK (0) job log log
2024/01/03 19:03 1h26m bisect fix android14-6.1 OK (0) job log log

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047]
CPU: 1 PID: 292 Comm: syz-executor460 Not tainted 6.1.145-syzkaller-00038-g3b4ff5af8d36 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:do_rmdir+0x1f2/0x6a0 fs/namei.c:4243
Code: ff ff 49 89 c6 48 3d 01 f0 ff ff 72 0d e8 b6 af af ff 45 89 f7 e9 94 00 00 00 4c 89 74 24 20 4d 8d 7e 30 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 df 12 f4 ff 49 83 3f 00 4c 8b 34
RSP: 0018:ffffc90000dc7e20 EFLAGS: 00010203
RAX: 0000000000000008 RBX: 1ffff920001b8fcc RCX: ffff88810caebcc0
RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff88810caebcc0
RBP: ffffc90000dc7ee8 R08: dffffc0000000000 R09: fffff520001b8fa1
R10: fffff520001b8fa1 R11: 1ffff920001b8fa0 R12: 00000000ffffff9c
R13: dffffc0000000000 R14: 0000000000000015 R15: 0000000000000045
FS:  00007f85d8d656c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e86cf11eb8 CR3: 000000010a716000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __do_sys_rmdir fs/namei.c:4270 [inline]
 __se_sys_rmdir fs/namei.c:4268 [inline]
 __x64_sys_rmdir+0x49/0x50 fs/namei.c:4268
 x64_sys_call+0x68e/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:85
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f85d8dc44f9
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:00007f85d8d65218 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 00007f85d8e513f8 RCX: 00007f85d8dc44f9
RDX: 00007f85d8da1c86 RSI: 0000000000000000 RDI: 0000200000000200
RBP: 00007f85d8e513f0 R08: 00007ffd63c6a3d7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f85d8e1e02c
R13: 000020000000c280 R14: 0000200000000200 R15: 00007ffd63c6a3d8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:do_rmdir+0x1f2/0x6a0 fs/namei.c:4243
Code: ff ff 49 89 c6 48 3d 01 f0 ff ff 72 0d e8 b6 af af ff 45 89 f7 e9 94 00 00 00 4c 89 74 24 20 4d 8d 7e 30 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 df 12 f4 ff 49 83 3f 00 4c 8b 34
RSP: 0018:ffffc90000dc7e20 EFLAGS: 00010203
RAX: 0000000000000008 RBX: 1ffff920001b8fcc RCX: ffff88810caebcc0
RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff88810caebcc0
RBP: ffffc90000dc7ee8 R08: dffffc0000000000 R09: fffff520001b8fa1
R10: fffff520001b8fa1 R11: 1ffff920001b8fa0 R12: 00000000ffffff9c
R13: dffffc0000000000 R14: 0000000000000015 R15: 0000000000000045
FS:  00007f85d8d656c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd63c69570 CR3: 000000010a716000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	49 89 c6             	mov    %rax,%r14
   3:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
   9:	72 0d                	jb     0x18
   b:	e8 b6 af af ff       	call   0xffafafc6
  10:	45 89 f7             	mov    %r14d,%r15d
  13:	e9 94 00 00 00       	jmp    0xac
  18:	4c 89 74 24 20       	mov    %r14,0x20(%rsp)
  1d:	4d 8d 7e 30          	lea    0x30(%r14),%r15
  21:	4c 89 f8             	mov    %r15,%rax
  24:	48 c1 e8 03          	shr    $0x3,%rax
* 28:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2d:	74 08                	je     0x37
  2f:	4c 89 ff             	mov    %r15,%rdi
  32:	e8 df 12 f4 ff       	call   0xfff41316
  37:	49 83 3f 00          	cmpq   $0x0,(%r15)
  3b:	4c                   	rex.WR
  3c:	8b                   	.byte 0x8b
  3d:	34                   	.byte 0x34

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/04 04:06 android14-6.1 3b4ff5af8d36 7368264b .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in do_rmdir
2024/12/21 17:40 android14-6.1 3e3f2b9e9fca d7f584ee .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in do_rmdir
2024/04/04 00:13 android14-6.1 af361f9a1066 51c4dcff .config strace log report syz C [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in do_rmdir
2023/12/04 16:26 android14-6.1 6465e29536ed f819d6f7 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in do_rmdir
* Struck through repros no longer work on HEAD.