Messages in this thread | | | Subject | Re: AW: PROBLEM: Kernel Oops in UDP stack | From | Eric Dumazet <> | Date | Thu, 2 Aug 2018 06:13:02 -0700 |
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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()
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