On Thu, Jun 9, 2022 at 3:25 PM Andrew Morton [off-list ref] wrote:

On Thu,  9 Jun 2022 22:16:19 +0000 Bill Wendling [off-list ref] wrote:

quoted

This patch set fixes some clang warnings when -Wformat is enabled.

tldr:

-       printk(msg);
+       printk("%s", msg);

the only reason to make this change is where `msg' could contain a `%'.
Generally, it came from userspace.

It helps kernel developers not accidentally to insert an unescaped '%'
in their messages, potentially exposing their code to an attack
vector.

Otherwise these changes are a
useless consumer of runtime resources.

Calling a "printf" style function is already insanely expensive. :-) I
understand that it's not okay blithely to increase runtime resources
simply because it's already slow, but in this case it's worthwhile.

I think it would be better to quieten clang in some fashion.

The "printk" and similar functions all have the "__printf" attribute.
I don't know of a modification to that attribute which can turn off
this type of check.

-bw