From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Laight <David.Laight@ACULAB.COM>,
'Marcel Hellwig' <mhellwig@mut-group.com>,
'Eric Dumazet' <eric.dumazet@gmail.com>,
"'davem@davemloft.net'" <davem@davemloft.net>,
"'kuznet@ms2.inr.ac.ru'" <kuznet@ms2.inr.ac.ru>,
"'yoshfuji@linux-ipv6.org'" <yoshfuji@linux-ipv6.org>,
"'andrew@lunn.ch'" <andrew@lunn.ch>
Cc: "'netdev@vger.kernel.org'" <netdev@vger.kernel.org>,
"'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
Matthias Wystrik <mwystrik@mut-group.com>
Subject: Re: AW: PROBLEM: Kernel Oops in UDP stack
Date: Thu, 2 Aug 2018 06:13:02 -0700 [thread overview]
Message-ID: <405319c1-2fa0-e1b5-7173-b19d9769d98a@gmail.com> (raw)
In-Reply-To: <d16f03bf47b24313ad9f2ff4e37d6274@AcuMS.aculab.com>
On 08/02/2018 02:17 AM, David Laight wrote:
> From: Marcel Hellwig
>> Sent: 01 August 2018 11:36
>>>> [<c0228adc>] (udp_recvmsg+0x284/0x33c) from [<c02306e0>] (inet_recvmsg+0x38/0x4c):
>> net/ipv4/udp.c:1234
>>>
>>> sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
>>>
>>> Unaligned access trap (virtual address c14fe63a), so either sin or ip_hdr(skb) are not on a 32bit
>> alignment
>>>
>>> Can you produce the disassembly of the trapping instruction ?
>>
>> https://gist.github.com/hellow554/6b11c6c0827d5db80a7e66f71f5636ff#file-net_uipv4_udp-lst-L1892-L1895
>>
>> sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
>> c0228ad8: e5943080 ldr r3, [r4, #128] ; 0x80
>> c0228adc: e593300c ldr r3, [r3, #12]
>> c0228ae0: e5823004 str r3, [r2, #4]
>
> There are actually 2 faults, difficult to quickly sort out the merged tracebacks.
> You are also running a rather old kernel: Linux version 3.4.113.
>
> It may well be that whichever ethernet driver generated the misaligned frame
> has since been fixed.
A misalign frame driver problem would have faulted earlier in IP stack,
much before we perform the copy to user space in udp_recvmsg()
next prev parent reply other threads:[~2018-08-02 13:13 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-31 15:06 PROBLEM: Kernel Oops in UDP stack Marcel Hellwig
2018-07-31 15:59 ` Eric Dumazet
2018-08-01 5:55 ` AW: " Marcel Hellwig
2018-08-01 10:20 ` Eric Dumazet
2018-08-01 10:35 ` AW: " Marcel Hellwig
2018-08-01 10:44 ` Paolo Abeni
2018-08-01 10:49 ` Eric Dumazet
2018-08-01 11:25 ` Eric Dumazet
2018-08-01 11:31 ` AW: " Marcel Hellwig
2018-08-01 13:27 ` Marcel Hellwig
2018-08-02 11:02 ` Marcel Hellwig
2018-08-02 13:05 ` Eric Dumazet
2018-08-02 9:17 ` David Laight
2018-08-02 13:13 ` Eric Dumazet [this message]
2018-08-02 13:18 ` David Laight
2018-08-02 13:57 ` AW: " Marcel Hellwig
2018-08-02 15:07 ` Eric Dumazet
2018-08-03 8:24 ` AW: " Marcel Hellwig
2018-08-07 13:42 ` Marcel Hellwig
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