Re: [PATCH] net/mlx5: fix a -Wstringop-truncation warning

[Saeed Mahameed]

On Fri, 2019-08-23 at 15:56 -0400, Qian Cai wrote:
> In file included from ./arch/powerpc/include/asm/paca.h:15,
>                  from ./arch/powerpc/include/asm/current.h:13,
>                  from ./include/linux/thread_info.h:21,
>                  from ./include/asm-generic/preempt.h:5,
>                  from
> ./arch/powerpc/include/generated/asm/preempt.h:1,
>                  from ./include/linux/preempt.h:78,
>                  from ./include/linux/spinlock.h:51,
>                  from ./include/linux/wait.h:9,
>                  from ./include/linux/completion.h:12,
>                  from ./include/linux/mlx5/driver.h:37,
>                  from
> drivers/net/ethernet/mellanox/mlx5/core/lib/eq.h:6,
>                  from
> drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c:33:
> In function 'strncpy',
>     inlined from 'mlx5_fw_tracer_save_trace' at
> drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c:549:2,
>     inlined from 'mlx5_tracer_print_trace' at
> drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c:574:2:
> ./include/linux/string.h:305:9: warning: '__builtin_strncpy' output
> may
> be truncated copying 256 bytes from a string of length 511
> [-Wstringop-truncation]
>   return __builtin_strncpy(p, q, size);
>          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Fix it by using the new strscpy_pad() since the commit 458a3bf82df4
> ("lib/string: Add strscpy_pad() function") which will always
> NUL-terminate the string, and avoid possibly leak data through the
> ring
> buffer where non-admin account might enable these events through
> perf.
> 
> Fixes: fd1483fe1f9f ("net/mlx5: Add support for FW reporter dump")
> Signed-off-by: Qian Cai <cai@xxxxxx>


Hi Qian and thanks for your patch,

We already have a patch that handles this issue, please check it out:
https://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux.git/commit/?h=net-next-mlx5