On Fri, Mar 20, 2026 at 04:19:16PM +0100, Arnd Bergmann wrote:

From: Arnd Bergmann <arnd@arndb.de>

Three sfc drivers contain the same *_fill_test() function that takes
a format string argument that gets passed down to snprintf(), producing
a warning with clang-22:

drivers/net/ethernet/sfc/falcon/ethtool.c:227:60: error: diagnostic behavior may be improved by adding
      the 'format(printf, 7, 8)' attribute to the declaration of 'ef4_fill_test' [-Werror,-Wmissing-format-attribute]
  210 |                 snprintf(test_str, sizeof(test_str), test_format, test_id);
      |                                                                          ^
drivers/net/ethernet/sfc/falcon/ethtool.c:210:13: note: 'ef4_fill_test' declared here

Rework these to take a varargs based test_format that allows better
type checking and avoids this warning.

Fixes: 3273c2e8c66a ("[netdrvr] sfc: sfc: Add self-test support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Nice rework!

Reviewed-by: Kees Cook <kees@kernel.org>

-- 
Kees Cook