Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in unix_shutdown

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Resending as plain text

On 8/21/21 11:43 AM, Shoaib Rao wrote:

I just tested my changes using the C reproducer and do not see the issue. andy.lavr@xxxxxxxxx had contacted me earlier in the week about a similar panic and I tested shutdown and could not reproduce the panic, Andy tracked it down to

https://lore.kernel.org/patchwork/patch/1479867/ <https://urldefense.com/v3/__https://lore.kernel.org/patchwork/patch/1479867/__;!!ACWV5N9M2RV99hQ!dCQkqhyYNMmbH4T4zQ7Ko0sVqSmut7DBj-QmuLRiHuH4xiBwxXc5cbtLaZgKdYGH$>

If that is not the culprit please let me know.

Shoaib


On 8/21/21 8:19 AM, syzbot wrote:
Hello,

syzbot found the following issue on:

HEAD commit:    9803fb968c8c Add linux-next specific files for 20210817
git tree:       linux-next
console output:https://syzkaller.appspot.com/x/log.txt?x=1727c65e300000
kernel config:https://syzkaller.appspot.com/x/.config?x=681282daead30d81
dashboard link:https://syzkaller.appspot.com/bug?extid=cd7ceee0d3b5892f07af
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro:https://syzkaller.appspot.com/x/repro.syz?x=13fb6ff9300000
C reproducer:https://syzkaller.appspot.com/x/repro.c?x=15272861300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:syzbot+cd7ceee0d3b5892f07af@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 6f812067 P4D 6f812067 PUD 6fe2f067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 6569 Comm: syz-executor133 Not tainted 5.14.0-rc6-next-20210817-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc90002dcfe38 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffff8d27cfa0 RCX: 0000000000000000
RDX: 1ffffffff1a4fa0a RSI: ffffffff87d03085 RDI: ffff888077074d80
RBP: ffff888077074d80 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff87d03004 R11: 0000000000000001 R12: 0000000000000001
R13: ffff888077075398 R14: ffff888077075b58 R15: ffff888077074e00
FS:  0000000001747300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000006f93f000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  unix_shutdown+0x28a/0x5b0 net/unix/af_unix.c:2857
  __sys_shutdown_sock net/socket.c:2242 [inline]
  __sys_shutdown_sock net/socket.c:2236 [inline]
  __sys_shutdown+0xf1/0x1b0 net/socket.c:2254
  __do_sys_shutdown net/socket.c:2262 [inline]
  __se_sys_shutdown net/socket.c:2260 [inline]
  __x64_sys_shutdown+0x50/0x70 net/socket.c:2260
  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
  entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43ee29
Code: 28 c3 e8 2a 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:00007ffdc0b3c908 EFLAGS: 00000246 ORIG_RAX: 0000000000000030
RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043ee29
RDX: 00000000004ac018 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000402e10 R08: 0000000000000000 R09: 0000000000400488
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402ea0
R13: 0000000000000000 R14: 00000000004ac018 R15: 0000000000400488
Modules linked in:
CR2: 0000000000000000
---[ end trace f541a02ac6ed69b5 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: 0018:ffffc90002dcfe38 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffffff8d27cfa0 RCX: 0000000000000000
RDX: 1ffffffff1a4fa0a RSI: ffffffff87d03085 RDI: ffff888077074d80
RBP: ffff888077074d80 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff87d03004 R11: 0000000000000001 R12: 0000000000000001
R13: ffff888077075398 R14: ffff888077075b58 R15: ffff888077074e00
FS:  0000000001747300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000006f93f000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
    0:	28 c3                	sub    %al,%bl
    2:	e8 2a 14 00 00       	callq  0x1431
    7:	66 2e 0f 1f 84 00 00 	nopw   %cs:0x0(%rax,%rax,1)
    e:	00 00 00
   11:	48 89 f8             	mov    %rdi,%rax
   14:	48 89 f7             	mov    %rsi,%rdi
   17:	48 89 d6             	mov    %rdx,%rsi
   1a:	48 89 ca             	mov    %rcx,%rdx
   1d:	4d 89 c2             	mov    %r8,%r10
   20:	4d 89 c8             	mov    %r9,%r8
   23:	4c 8b 4c 24 08       	mov    0x8(%rsp),%r9
   28:	0f 05                	syscall
   2a:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax <-- trapping instruction
   30:	73 01                	jae    0x33
   32:	c3                   	retq
   33:	48 c7 c1 c0 ff ff ff 	mov    $0xffffffffffffffc0,%rcx
   3a:	f7 d8                	neg    %eax
   3c:	64 89 01             	mov    %eax,%fs:(%rcx)
   3f:	48                   	rex.W


---
This report is generated by a bot. It may contain errors.
Seehttps://goo.gl/tpsmEJ  for more information about syzbot.
syzbot engineers can be reached atsyzkaller@xxxxxxxxxxxxxxxx.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status  for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches



[Index of Archives]     [Linux Samsung SoC]     [Linux Rockchip SoC]     [Linux Actions SoC]     [Linux for Synopsys ARC Processors]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]


  Powered by Linux