syzbot


general protection fault in hci_uart_tty_ioctl

Status: upstream: reported C repro on 2023/06/04 06:24
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+aeec2b0228ee92ab04b8@syzkaller.appspotmail.com
First crash: 266d, last: 175d
Fix commit to backport (bisect log) :
tree: upstream
commit 9c33663af9ad115f90c076a1828129a3fbadea98
Author: Lee, Chun-Yi <joeyli.kernel@gmail.com>
Date: Mon Jul 10 15:17:23 2023 +0000

  Bluetooth: hci_ldisc: check HCI_UART_PROTO_READY flag in HCIUARTGETPROTO

  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: BUG: unable to handle kernel NULL pointer dereference in hci_uart_tty_ioctl (log)
Repro: C syz .config
  
Bug presence (3)
Date Name Commit Repro Result
2023/09/03 linux-6.1.y (ToT) c2cbfe5f5122 C [report] general protection fault in hci_uart_tty_ioctl
2023/06/04 upstream (ToT) e5282a7d8f6b C [report] general protection fault in hci_uart_tty_ioctl
2023/09/03 upstream (ToT) 92901222f83d C Didn't crash
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 general protection fault in hci_uart_tty_ioctl origin:upstream missing-backport C done 1 72d 272d 0/3 upstream: reported C repro on 2023/05/29 05:45
upstream general protection fault in hci_uart_tty_ioctl bluetooth C error done 4 180d 558d 0/26 auto-obsoleted due to no activity on 2023/12/07 13:40
android-54 general protection fault in hci_uart_tty_ioctl C 2 590d 590d 0/2 auto-obsoleted due to no activity on 2023/04/19 15:38
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2023/09/16 11:52 6h27m fix candidate upstream job log (1)
2023/07/08 05:20 3h27m bisect fix linux-6.1.y job log (0) log

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 3680 Comm: syz-executor252 Not tainted 6.1.31-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:hci_uart_tty_ioctl+0x2a0/0xa20 drivers/bluetooth/hci_ldisc.c:774
Code: e9 f9 49 81 c4 b8 00 00 00 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 5b 7d 3f fa 49 8b 1c 24 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 65 06 00 00 8b 2b e9 39 07 00 00 e8 07
RSP: 0018:ffffc90003d2fe40 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88801e63bb80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880778165f8 R08: ffffffff87a09ee0 R09: ffffed1003f1d584
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88801f8eacb8
R13: dffffc0000000000 R14: ffff888077816000 R15: 0000000000000000
FS:  00007fe2460cc700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe246190ae8 CR3: 000000001e5f5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 tty_ioctl+0x88e/0xbd0 drivers/tty/tty_io.c:2782
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
 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+0x63/0xcd
RIP: 0033:0x7fe24613b8c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe2460cc318 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe2461c33f8 RCX: 00007fe24613b8c9
RDX: 0000000000000000 RSI: 00000000800455c9 RDI: 0000000000000003
RBP: 00007fe2461c33f0 R08: 00007fe2460cc700 R09: 0000000000000000
R10: 00007fe2460cc700 R11: 0000000000000246 R12: 6d74702f7665642f
R13: 00007ffffe681b5f R14: 00007fe2460cc400 R15: 0000000000022000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:hci_uart_tty_ioctl+0x2a0/0xa20 drivers/bluetooth/hci_ldisc.c:774
Code: e9 f9 49 81 c4 b8 00 00 00 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 5b 7d 3f fa 49 8b 1c 24 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 65 06 00 00 8b 2b e9 39 07 00 00 e8 07
RSP: 0018:ffffc90003d2fe40 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88801e63bb80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880778165f8 R08: ffffffff87a09ee0 R09: ffffed1003f1d584
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88801f8eacb8
R13: dffffc0000000000 R14: ffff888077816000 R15: 0000000000000000
FS:  00007fe2460cc700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe24617ca70 CR3: 000000001e5f5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	e9 f9 49 81 c4       	jmpq   0xc48149fe
   5:	b8 00 00 00 4c       	mov    $0x4c000000,%eax
   a:	89 e0                	mov    %esp,%eax
   c:	48 c1 e8 03          	shr    $0x3,%rax
  10:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  15:	74 08                	je     0x1f
  17:	4c 89 e7             	mov    %r12,%rdi
  1a:	e8 5b 7d 3f fa       	callq  0xfa3f7d7a
  1f:	49 8b 1c 24          	mov    (%r12),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 65 06 00 00    	jne    0x69c
  37:	8b 2b                	mov    (%rbx),%ebp
  39:	e9 39 07 00 00       	jmpq   0x777
  3e:	e8                   	.byte 0xe8
  3f:	07                   	(bad)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/06/04 06:24 linux-6.1.y d2869ace6eeb a4ae4f42 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in hci_uart_tty_ioctl
* Struck through repros no longer work on HEAD.