Re: [RFC PATCH i-g-t] lib: Add warning if lockdep is disabled before a test.

Daniel Vetter
2016-04-20T14:17:39Z

On Tue, Apr 19, 2016 at 03:12:38PM +0200, Maarten Lankhorst wrote:
> When running tests, it will produce warnings like this:
>
> (core_auth:2552) igt-core-WARNING: Lockdep is turned off.
>
> This makes sure lockdep warnings during load aren't accidentally ignored.
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

Ack on the idea.
-Daniel

> ---
> Unfortunately this version suffers from a small problem, piglit still succeeds without WARN. :(
>
> Seems to be an issue in piglit/tests/igt.py that needs a separate fix.
>
> diff --git a/lib/igt_core.c b/lib/igt_core.c
> index 832361b0a9f9..bb17ddfbcadb 100644
> --- a/lib/igt_core.c
> +++ b/lib/igt_core.c
> @@ -570,6 +570,39 @@ static void oom_adjust_for_doom(void)
>
> }
>
> +static void igt_warn_lockdep(void)
> +{
> + FILE *f;
> + long val;
> + char line[256];
> +
> + f = fopen("/proc/lockdep_stats", "r");
> + if (!f && errno == ENOENT) {
> + igt_debug("Lockdep is not compiled in.\n");
> + return;
> + }
> +
> + igt_assert(f);
> +
> + while (fgets(line, sizeof(line), f)) {
> + if (strncmp(line, " debug_locks:", 13))
> + continue;
> +
> + val = strtol(line + 13, NULL, 10);
> +
> + if (!val)
> + igt_warn("Lockdep is turned off.\n");
> + else
> + igt_debug("Lockdep is active.\n");
> + goto out;
> + }
> +
> + igt_warn("Could not find lockdep setting.\n");
> +
> +out:
> + fclose(f);
> +}
> +
> static int common_init(int *argc, char **argv,
> const char *extra_short_opts,
> const struct option *extra_long_opts,
> @@ -741,6 +774,8 @@ out:
> low_mem_killer_disable(true);
> }
>
> + igt_warn_lockdep();
> +
> /* install exit handler, to ensure we clean up */
> igt_install_exit_handler(common_exit_handler);
>
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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