On Thu, Mar 12, 2026 at 11:34:41PM -0700, Yosry Ahmed wrote:
> > diff --git a/tools/testing/selftests/cgroup/test_zswap.c
> > b/tools/testing/selftests/cgroup/test_zswap.c
> > index 64ebc3f3f203..e69d845d3592 100644
> > --- a/tools/testing/selftests/cgroup/test_zswap.c
> > +++ b/tools/testing/selftests/cgroup/test_zswap.c
> > @@ -589,9 +589,21 @@ struct zswap_test {
> > };
> > #undef T
> >
> > -static bool zswap_configured(void)
> > +static void check_zswap_enabled(void)
> > {
> > - return access("/sys/module/zswap", F_OK) == 0;
> > + char value[2];
>
> Please wait for discussions on the previous version to conclude and
> give people a little bit of time to respond before sending the next
> version.
Sorry for the rush. I thought that I had clarified the issue there.
> I think this can just be be:
>
> char value;
> ...
>
> if (read_text(.., &value, sizeof(value)) < 0)
This actuall introduce a problem to the code, as in read_text()
that achivement is:
len = read(fd, buf, max_len - 1);
When 'sizeof(value) == 1' pass in that makes read(fd, &value, 0);
read zero, after that, the value is set to '\0'.
With your < 0 check, this is treated as success, then value == 'N' is false,
the check_zswap_enabled will report wrong status (enabled) on disabled.
--
Regards,
Li Wang
