On Wed, 28 Oct 2026 10:28:10 +0900
"Masami Hiramatsu (Google)" [off-list ref] wrote:
Hmm, IMHO, there is a bad implementation in __ftrace_set_clr_event_nolock().
It should make a working copy of the filter string and pass it to
apply_event_filter(). Or pass the filter string as `const char *`
so that it is copied in the apply_event_filter() side. The ownership
of the filter string is not clear here.
I noticed this when I applied the patch.
Yes, the correct solution is to pass in const char *filter to
__ftrace_set_clr_event_nolock() (I was planning on doing this after the
merge window closed). But no, making a copy in
__ftrace_set_clr_event_nolock() is *not* the right solution. There's
nothing in that function that modifies that string to suggest it needs to
make a copy of it.
The correct solution is to pass const char *filter to apply_event_filter()
and have *that* function do the copy. That was my plan to make a patch for.
-- Steve