Messages in this thread | | | Subject | Re: AW: AW: PROBLEM: Kernel Oops in UDP stack | From | Paolo Abeni <> | Date | Wed, 01 Aug 2018 12:44:22 +0200 |
| |
On Wed, 2018-08-01 at 10:35 +0000, Marcel Hellwig wrote: > > > [<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]
I *think* pskb_trim_rcsum() in __udp4_lib_rcv() can copy the ipv4 header to an unaligned address, for cloned skbs. If I understood correctly the relevant socket is a mcast one, so cloned skbs can land there.
Paolo
| |