[dm-devel] [PATCH] libmultipath: fix condlog NULL argument in uevent_get_env_var

[Martin Wilck]

On Thu, 2020-06-04 at 18:20 -0500, Benjamin Marzinski wrote:
> uevent_get_env_var() could call condlog with p == NULL. On gcc 10,
> this triggers warnings like:
> 
> In file included from uevent.c:47:
> In function 'uevent_get_env_var',
>     inlined from 'uevent_get_wwid' at uevent.c:170:8:
> debug.h:13:2: error: '%s' directive argument is null
> [-Werror=format-overflow=]
>    13 |  dlog(logsink, prio, fmt "\n", ##args)
>       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> uevent.c:132:2: note: in expansion of macro 'condlog'
>   132 |  condlog(4, "%s: %s -> '%s'", __func__, attr, p);
>       |  ^~~~~~~
> uevent.c: In function 'uevent_get_wwid':
> uevent.c:132:25: note: format string is defined here
>   132 |  condlog(4, "%s: %s -> '%s'", __func__, attr, p);
>       |                         ^~
> 
> If p is NULL, use "(null)" instead.
> 
> Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> ---
>  libmultipath/uevent.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Martin Wilck <mwilck at suse.com>