Re: [dpdk-stable] [dpdk-dev] [PATCH] examples/l3fwd: fix unaligned memory access

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 25-Jul-19 2:27 PM, Aaron Conole wrote:
> hgovindh <hariprasad.govindharajan@intel.com> writes:
> 
>> Fix unaligned memory access when reading IPv6 header which
>> leads to segmentation fault by changing aligned memory read
>> to unaligned memory read.
>>
>> Bugzilla ID: 279
>> Fixes: 64d3955de1de ("examples/l3fwd: fix ARM build")
>> Cc: maciej.czekaj@caviumnetworks.com
>> Cc: stable@dpdk.org
>> Signed-off-by: hgovindh <hariprasad.govindharajan@intel.com>
>> ---
>>   examples/l3fwd/l3fwd_em.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/examples/l3fwd/l3fwd_em.c b/examples/l3fwd/l3fwd_em.c
>> index fa8f82be6..f0c443dae 100644
>> --- a/examples/l3fwd/l3fwd_em.c
>> +++ b/examples/l3fwd/l3fwd_em.c
>> @@ -285,7 +285,7 @@ em_get_ipv6_dst_port(void *ipv6_hdr, uint16_t portid, void *lookup_struct)
>>   	 * Get part of 5 tuple: dst IP address lower 96 bits
>>   	 * and src IP address higher 32 bits.
>>   	 */
>> -	key.xmm[1] = *(xmm_t *)data1;
>> +	key.xmm[1] = _mm_loadu_si128((xmm_t *)data1);
> 
> Nak.  Please use a generic unaligned load, rather than an intel specific
> one.  Otherwise, supported platforms like arm64 will have broken builds.
> 
> Additionally, which chip and compiler did you use to get this error?

I have reproduced this error on Intel Xeon E5-2699 and GCC 7.4 (Ubuntu 
18.04).

> 
>>   
>>   	/*
>>   	 * Get part of 5 tuple: dst port and src port
> 


-- 
Thanks,
Anatoly