syzbot


general protection fault in vfs_link

Status: upstream: reported C repro on 2024/02/24 15:03
Bug presence: origin:downstream
[Documentation on labels]
Reported-by: syzbot+8f25cdaf6708f0536ad6@syzkaller.appspotmail.com
First crash: 139d, last: 5d23h
Bug presence (3)
Date Name Commit Repro Result
2024/02/24 android13-5.15-lts (ToT) 993bed180178 C [report] general protection fault in vfs_link
2024/02/24 lts (merge base) 6139f2a02fe0 C Didn't crash
2024/02/24 upstream (ToT) 603c04e27c3e C Didn't crash
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 general protection fault in vfs_link origin:downstream C 1 6d19h 140d 0/2 upstream: reported C repro on 2024/02/23 21:10
android-5-10 general protection fault in vfs_link C inconclusive 3 90d 150d 0/2 upstream: reported C repro on 2024/02/13 06:42
android-54 general protection fault in vfs_link C 1 59d 143d 0/2 upstream: reported C repro on 2024/02/20 15:20
Fix bisection attempts (4)
Created Duration User Patch Repo Result
2024/07/07 04:47 37m bisect fix android13-5.15-lts OK (0) job log log
2024/05/28 10:00 33m bisect fix android13-5.15-lts OK (0) job log log
2024/04/25 22:51 59m bisect fix android13-5.15-lts OK (0) job log log
2024/03/25 19:38 34m bisect fix android13-5.15-lts OK (0) job log 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-executor244 Not tainted 5.15.148-syzkaller-00718-g993bed180178 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:vfs_link+0x40/0x7f0 fs/namei.c:4519
Code: 89 cd 49 89 d6 48 89 75 c0 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 ff 3d b2 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 81 4e f4 ff 48 8b 03 48 89 45 d0
RSP: 0018:ffffc9000078fba8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff88811f0a62c0
RDX: 0000000000000000 RSI: ffffffff868f33c0 RDI: 0000000000000000
RBP: ffffc9000078fc10 R08: 0000000000000000 R09: ffffed1021260619
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88811bd90990 R14: ffff888109303018 R15: ffff888109303018
FS:  00005555568ff480(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 0000000119047000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 incfs_link fs/incfs/vfs.c:610 [inline]
 dir_link+0x347/0x4c0 fs/incfs/vfs.c:1285
 vfs_link+0x645/0x7f0 fs/namei.c:4563
 do_linkat+0x34d/0x9f0 fs/namei.c:4634
 __do_sys_linkat fs/namei.c:4662 [inline]
 __se_sys_linkat fs/namei.c:4659 [inline]
 __x64_sys_linkat+0xe9/0x100 fs/namei.c:4659
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f3412d7bc69
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:00007ffeafbb6338 EFLAGS: 00000246 ORIG_RAX: 0000000000000109
RAX: ffffffffffffffda RBX: 00007ffeafbb6340 RCX: 00007f3412d7bc69
RDX: 0000000000000004 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 00007ffeafbb6348 R08: 0000000000000000 R09: 00007f3412d4bbe0
R10: 0000000020000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeafbb65a8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 1e0b7e1962694c20 ]---
RIP: 0010:vfs_link+0x40/0x7f0 fs/namei.c:4519
Code: 89 cd 49 89 d6 48 89 75 c0 48 89 fb 49 bc 00 00 00 00 00 fc ff df e8 ff 3d b2 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 81 4e f4 ff 48 8b 03 48 89 45 d0
RSP: 0018:ffffc9000078fba8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000030 RCX: ffff88811f0a62c0
RDX: 0000000000000000 RSI: ffffffff868f33c0 RDI: 0000000000000000
RBP: ffffc9000078fc10 R08: 0000000000000000 R09: ffffed1021260619
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88811bd90990 R14: ffff888109303018 R15: ffff888109303018
FS:  00005555568ff480(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 0000000119047000 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 ff 3d b2 ff       	call   0xffb23e1a
  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 81 4e f4 ff       	call   0xfff44eba
  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
2024/02/24 15:02 android13-5.15-lts 993bed180178 8d446f15 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in vfs_link
* Struck through repros no longer work on HEAD.