syzbot


general protection fault in chrdev_open

Status: upstream: reported C repro on 2022/06/07 21:34
Reported-by: syzbot+d1de589e018e6b4b8168@syzkaller.appspotmail.com
First crash: 172d, last: 172d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Read in chrdev_open C error 14 88d 654d 0/1 upstream: reported C repro on 2021/02/11 04:55
android-5-10 general protection fault in chrdev_open C error 1 172d 171d 0/2 upstream: reported C repro on 2022/06/08 15:37
linux-4.14 KASAN: use-after-free Read in chrdev_open C error 4 89d 662d 0/1 upstream: reported C repro on 2021/02/03 08:18

Sample crash report:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 304 Comm: syz-executor115 Not tainted 5.4.190-syzkaller-00008-gff81cbffa822 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:cdev_get fs/char_dev.c:350 [inline]
RIP: 0010:chrdev_open+0x6e/0x5b0 fs/char_dev.c:400
Code: 00 4c 89 f3 48 c1 eb 03 42 80 3c 23 00 74 08 4c 89 f7 e8 95 40 fb ff 4d 8b 2e 4d 85 ed 74 40 49 8d 5d 60 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 73 40 fb ff 48 8b 1b 48 85 db 0f
RSP: 0018:ffff8881de767a60 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000062 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff8881de767a24
RBP: ffffffff81916690 R08: dffffc0000000000 R09: ffffed103bcecf45
R10: ffffed103bcecf45 R11: 1ffff1103bcecf44 R12: dffffc0000000000
R13: 0000000000000002 R14: ffff8881e632ed30 R15: ffff8881e632eae8
FS:  0000555556ceb3c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055678e872698 CR3: 00000001e0cd6000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 do_dentry_open+0x7e3/0xef0 fs/open.c:796
 do_last fs/namei.c:3495 [inline]
 path_openat+0x1464/0x3710 fs/namei.c:3612
 do_filp_open+0x19a/0x3a0 fs/namei.c:3642
 do_sys_open+0x2e3/0x700 fs/open.c:1113
 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fcb6d085909
Code: 28 c3 e8 5a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc6a81f528 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffc6a81f538 RCX: 00007fcb6d085909
RDX: 0000000000000034 RSI: 0000000000080082 RDI: 0000000020000040
RBP: 00007ffc6a81f530 R08: 00007fcb6d043bd0 R09: 00007fcb6d043bd0
R10: 00007fcb6d043bd0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 82f5342df019752f ]---
RIP: 0010:cdev_get fs/char_dev.c:350 [inline]
RIP: 0010:chrdev_open+0x6e/0x5b0 fs/char_dev.c:400
Code: 00 4c 89 f3 48 c1 eb 03 42 80 3c 23 00 74 08 4c 89 f7 e8 95 40 fb ff 4d 8b 2e 4d 85 ed 74 40 49 8d 5d 60 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 73 40 fb ff 48 8b 1b 48 85 db 0f
RSP: 0018:ffff8881de767a60 EFLAGS: 00010206
RAX: 000000000000000c RBX: 0000000000000062 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff8881de767a24
RBP: ffffffff81916690 R08: dffffc0000000000 R09: ffffed103bcecf45
R10: ffffed103bcecf45 R11: 1ffff1103bcecf44 R12: dffffc0000000000
R13: 0000000000000002 R14: ffff8881e632ed30 R15: ffff8881e632eae8
FS:  0000555556ceb3c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055678e872698 CR3: 00000001e0cd6000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	00 4c 89 f3          	add    %cl,-0xd(%rcx,%rcx,4)
   4:	48 c1 eb 03          	shr    $0x3,%rbx
   8:	42 80 3c 23 00       	cmpb   $0x0,(%rbx,%r12,1)
   d:	74 08                	je     0x17
   f:	4c 89 f7             	mov    %r14,%rdi
  12:	e8 95 40 fb ff       	callq  0xfffb40ac
  17:	4d 8b 2e             	mov    (%r14),%r13
  1a:	4d 85 ed             	test   %r13,%r13
  1d:	74 40                	je     0x5f
  1f:	49 8d 5d 60          	lea    0x60(%r13),%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 73 40 fb ff       	callq  0xfffb40ac
  39:	48 8b 1b             	mov    (%rbx),%rbx
  3c:	48 85 db             	test   %rbx,%rbx
  3f:	0f                   	.byte 0xf

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-android-5-4-kasan 2022/06/07 21:33 android12-5.4 ff81cbffa822 b2706118 .config log report syz C general protection fault in chrdev_open
* Struck through repros no longer work on HEAD.