[PATCH v5 1/5] bug/kunit: Core support for suppressing warning backtraces
Peter Zijlstra
peterz at infradead.org
Fri May 30 09:25:07 UTC 2025
On Thu, May 29, 2025 at 10:46:15AM -0700, Kees Cook wrote:
> Doing it on the other end doesn't look great (see the other reply). I was
> suggesting it's not on fast path because the added code is a dependant
> conditional following an "unlikley" conditional. But if you wanted to
> push it totally out of line, we'd likely need to pass __func__ into
> warn_slowpath_fmt() and __warn_printk(), and then have __warn_printk()
warn_slowpath_fmt() already uses buildin_return_address(0), and then it
can use kallsyms to find the symbol name. No need to pass __func__ as a
string.
> return bool to make the call to __WARN_FLAGS() conditional. e.g.:
>
> - warn_slowpath_fmt(__FILE__, __LINE__, taint, arg); \
> + warn_slowpath_fmt(__FILE__, __LINE__, __func__, taint, arg); \
>
> and:
>
> - __warn_printk(arg); \
> - __WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\
> + if (__warn_printk(__func__, arg)) \
> + __WARN_FLAGS(BUGFLAG_NO_CUT_HERE | BUGFLAG_TAINT(taint));\
>
> But it still leaves bare __WARN unhandled...
Nah, don't propagate, just eat the __WARN and handle things in
__report_bug(), which is where they all end up.
But the real purpose here seems to be to supress printk output, so why
not use 'suppress_printk' ?
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