syzbot


general protection fault in vfs_link

Status: upstream: reported C repro on 2024/02/23 21:10
Bug presence: origin:downstream
[Documentation on labels]
Reported-by: syzbot+31c9badf7c59066fac27@syzkaller.appspotmail.com
First crash: 112d, last: 18d
Bug presence (3)
Date Name Commit Repro Result
2024/02/23 android14-6.1 (ToT) 8c0f9174731d C [report] general protection fault in vfs_link
2024/02/23 lts (merge base) ba6f5fb46511 C Didn't crash
2024/02/23 upstream (ToT) 603c04e27c3e C Didn't crash
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-15 general protection fault in vfs_link origin:downstream C 1 17d 111d 0/2 upstream: reported C repro on 2024/02/24 15:03
android-5-10 general protection fault in vfs_link C inconclusive 3 62d 122d 0/2 upstream: reported C repro on 2024/02/13 06:42
android-54 general protection fault in vfs_link C 1 31d 115d 0/2 upstream: reported C repro on 2024/02/20 15:20
Fix bisection attempts (3)
Created Duration User Patch Repo Result
2024/05/27 15:47 1h10m bisect fix android14-6.1 job log (0) log
2024/04/24 14:30 1h17m bisect fix android14-6.1 job log (0) log
2024/03/25 02:57 39m bisect fix android14-6.1 job log (0) log

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 1 PID: 296 Comm: syz-executor325 Not tainted 6.1.68-syzkaller-00029-g8c0f9174731d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:vfs_link+0x40/0x7f0 fs/namei.c:4485
Code: 89 cd 49 89 d6 48 89 75 c0 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 8f cd ac ff 48 89 5d a0 48 83 c3 30 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 71 8a f3 ff 48 8b 03 48 89 45 d0
RSP: 0018:ffffc90000e67ba8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff888108dfd100
RDX: 0000000000000000 RSI: ffffffff86cf9fe0 RDI: 0000000000000000
RBP: ffffc90000e67c10 R08: 0000000000000000 R09: ffffed10200ab3d6
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88811f508770 R14: ffff888100559e00 R15: ffff888100559e00
FS:  00005555573cd480(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000011ebc1000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 incfs_link fs/incfs/vfs.c:611 [inline]
 dir_link+0x347/0x4c0 fs/incfs/vfs.c:1286
 vfs_link+0x645/0x7f0 fs/namei.c:4529
 do_linkat+0x34d/0x9f0 fs/namei.c:4600
 __do_sys_linkat fs/namei.c:4628 [inline]
 __se_sys_linkat fs/namei.c:4625 [inline]
 __x64_sys_linkat+0xe9/0x100 fs/namei.c:4625
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6c1c515c69
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffec8eda488 EFLAGS: 00000246 ORIG_RAX: 0000000000000109
RAX: ffffffffffffffda RBX: 00007ffec8eda490 RCX: 00007f6c1c515c69
RDX: 0000000000000004 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 00007ffec8eda498 R08: 0000000000000000 R09: 00007f6c1c4e5be0
R10: 0000000020000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffec8eda6f8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vfs_link+0x40/0x7f0 fs/namei.c:4485
Code: 89 cd 49 89 d6 48 89 75 c0 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 8f cd ac ff 48 89 5d a0 48 83 c3 30 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 71 8a f3 ff 48 8b 03 48 89 45 d0
RSP: 0018:ffffc90000e67ba8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff888108dfd100
RDX: 0000000000000000 RSI: ffffffff86cf9fe0 RDI: 0000000000000000
RBP: ffffc90000e67c10 R08: 0000000000000000 R09: ffffed10200ab3d6
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88811f508770 R14: ffff888100559e00 R15: ffff888100559e00
FS:  00005555573cd480(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000011ebc1000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	89 cd                	mov    %ecx,%ebp
   2:	49 89 d6             	mov    %rdx,%r14
   5:	48 89 75 c0          	mov    %rsi,-0x40(%rbp)
   9:	48 89 fb             	mov    %rdi,%rbx
   c:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  13:	fc ff df
  16:	e8 8f cd ac ff       	call   0xffaccdaa
  1b:	48 89 5d a0          	mov    %rbx,-0x60(%rbp)
  1f:	48 83 c3 30          	add    $0x30,%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 71 8a f3 ff       	call   0xfff38aaa
  39:	48 8b 03             	mov    (%rbx),%rax
  3c:	48 89 45 d0          	mov    %rax,-0x30(%rbp)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/23 21:08 android14-6.1 8c0f9174731d 8d446f15 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vfs_link
* Struck through repros no longer work on HEAD.