Re: [regression] nf_iterate(), BUG: unable to handle kernel NULL pointer dereference

Pekka Enberg
2008-07-24T12:44:28Z

On Thu, Jul 24, 2008 at 3:03 PM, Patrick McHardy <kaber@trash.net> wrote:
> Ingo Molnar wrote:
>>
>> * Ingo Molnar <mingo@elte.hu> wrote:
>>
>>> here's a new type of crash a -tip testbox triggered today:
>>>
>>> BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
>>> IP: [<0000000000000000>] 0x0
>>> PGD 0 Oops: 0010 [1] PREEMPT CPU 0 Pid: 5331, comm: ssh Not tainted
>>> 2.6.26 #21613
>>> RIP: 0010:[<0000000000000000>] [<0000000000000000>] 0x0
>>> RSP: 0018:ffff88003b959a70 EFLAGS: 00010217
>>> RAX: ffff88003b9ba91c RBX: ffff88003b9baac0 RCX: 0000000000000002
>>> RDX: ffff88003b9baac0 RSI: 0000000000000014 RDI: ffff88003b9ba3d8
>>> RBP: ffff88003b959a98 R08: ffff88003e434130 R09: ffff88003b9598b8
>>> R10: 0000000000002000 R11: 00000000d85507ac R12: ffff88003b9ba3d8
>>> R13: 0000000000000002 R14: ffff88003e06a020 R15: 0000000000000000
>>> FS: 00007fb2b7806780(0000) GS:ffffffff80c1c180(0000)
>>> knlGS:0000000000000000
>>> CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>>> CR2: 0000000000000000 CR3: 000000003b9e8000 CR4: 00000000000006a0
>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>>> Process ssh (pid: 5331, threadinfo ffff88003b958000, task
>>> ffff88003b99a000)
>>> Stack: ffffffff80777f25 ffff88003b959a98 ffffffff80c24170
>>> ffff88003b959b28
>>> 0000000000000004 ffff88003b959ae8 ffffffff80733107 ffff88003b959ab8
>>> ffff88003b9ba3d8 ffffffff80c1ed60 0000000000000004 ffff88003b9ba3d8
>>> Call Trace:
>>> [<ffffffff80777f25>] ? ipv4_confirm+0x8d/0x122
>>> [<ffffffff80733107>] nf_iterate+0x43/0xa5
>
> Does reverting 31d8519c fix this?

Hmm, why do you think it's related? It looks like elem->hook() is a
NULL pointer but my patch shouldn't make any difference here...