Re: [dpdk-dev] [PATCH] test/table: fix build with GCC 11

[Thomas Monjalon <thomas@monjalon.net>]

17/05/2021 17:57, Ferruh Yigit:
> Build error:
> ../app/test/test_table_tables.c: In function ‘test_table_stub’:
> ../app/test/test_table_tables.c:31:9:
> 	warning: ‘memset’ offset [0, 31] is out of the bounds [0, 0]
> 	[-Warray-bounds]
>          memset((uint8_t *)mbuf + sizeof(struct rte_mbuf) + 32, 0, 32); \
>          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../app/test/test_table_tables.c:151:25:
> 	note: in expansion of macro ‘PREPARE_PACKET’
>   151 |                         PREPARE_PACKET(mbufs[i], 0xadadadad);
>       |                         ^~~~~~~~~~~~~~
> 
> 'key' points to mbuf header + 32 bytes, and memset clears next 32 bytes
> of 'key', so overall there needs to be 64 bytes after mbuf header.
> Adding a mbuf size check before memset.
> 
> The original code has an assumption that mbuf data buffer follows mbuf
> header, this patch accepts same assumption.
> 
> Bugzilla ID: 677
> Fixes: 5205954791cb ("app/test: packet framework unit tests")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> Cc: cristian.dumitrescu@intel.com
> Cc: Kevin Traynor <ktraynor@redhat.com>
> 
> Not exactly clear why compiler complains about, compiler can't know the
> bounds of the memory we try to memset here.
> But adding a size check seems logic thing to do also fixes the compiler
> warning.

Applied, thanks