Subject: Re: [PATCH V3] tools/perf: Fix the check for parameterized field in event term

From: Namhyung Kim <[email-masked]>
Date: Sun, 26 Apr 2026 23:01:07 -0700

On Sun, Apr 26, 2026 at 01:30:56PM +0530, Athira Rajeev wrote:
> The format_alias() function in util/pmu.c has a check to
> detect whether the event has parameterized field ( =? ).
> The string alias->terms contains the event and if the event
> has user configurable parameter, there will be presence of
> sub string "=?" in the alias->terms.
> 
> Snippet of code:
> 
>  /* Paramemterized events have the parameters shown. */
>        if (strstr(alias->terms, "=?")) {
>                /* No parameters. */
>                snprintf(buf, len, "%.*s/%s/", (int)pmu_name_len, pmu->name, alias->name);
> 
> if "strstr" contains the substring, it returns a pointer
> and hence enters the above check which is not the expected
> check. And hence "perf list" doesn't have the parameterized
> fields in the result.
> 
> Fix this check to use:
> 
> if (!strstr(alias->terms, "=?")) {
> 
> With this change, perf list shows the events correctly with
> the strings showing parameters.
> 
> Other changes in this patch:
> - Replace snprintf with scnprintf in buffer offset calculations to
> ensure the 'used' count will not exceed the "len"

Please split this change into a separate commit.  Ideally each commit
would do one thing at a time.

Thanks,
Namhyung