On Thu, Jan 13, 2022 at 03:51:08PM -0800, John.C.Harrison@xxxxxxxxx wrote:
> From: John Harrison <John.C.Harrison@xxxxxxxxx>
>
> Some of the IGT framework relies on receving a uevent when a hang
> occurs. So add a test that this actually works.
>
> While testing this, noticed that hangs could sometimes be missed
> because the uevent was (presumably) still in flight by the time the
> handler was de-registered. So add an extra delay during cleanup to
> give the uevent chance to arrive.
>
> Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx>
Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> ---
> lib/igt_aux.c | 7 +++++++
> tests/i915/i915_hangman.c | 43 +++++++++++++++++++++++++++++++++++++++
> 2 files changed, 50 insertions(+)
>
> diff --git a/lib/igt_aux.c b/lib/igt_aux.c
> index c247a1aa4..03cc38c93 100644
> --- a/lib/igt_aux.c
> +++ b/lib/igt_aux.c
> @@ -523,6 +523,13 @@ void igt_fork_hang_detector(int fd)
>
> void igt_stop_hang_detector(void)
> {
> + /*
> + * Give the uevent time to arrive. No sleep at all misses about 20% of
> + * hangs (at least, in the i915_hangman/detector test). A sleep of 1ms
> + * seems to miss about 2%, 10ms loses <1%, so 100ms should be safe.
> + */
> + usleep(100 * 1000);
> +
> igt_stop_helper(&hang_detector);
> }
>
> diff --git a/tests/i915/i915_hangman.c b/tests/i915/i915_hangman.c
> index 7b8390a6c..354769f39 100644
> --- a/tests/i915/i915_hangman.c
> +++ b/tests/i915/i915_hangman.c
> @@ -31,6 +31,7 @@
> #include <sys/stat.h>
> #include <sys/types.h>
> #include <fcntl.h>
> +#include <signal.h>
>
> #include "i915/gem.h"
> #include "i915/gem_create.h"
> @@ -289,6 +290,38 @@ test_engine_hang(const intel_ctx_t *ctx,
> put_ahnd(ahnd);
> }
>
> +static int hang_count;
> +
> +static void sig_io(int sig)
> +{
> + hang_count++;
> +}
> +
> +static void test_hang_detector(const intel_ctx_t *ctx,
> + const struct intel_execution_engine2 *e)
> +{
> + igt_hang_t hang;
> + uint64_t ahnd = get_reloc_ahnd(device, ctx->id);
> +
> + hang_count = 0;
> +
> + igt_fork_hang_detector(device);
> +
> + /* Steal the signal handler */
> + signal(SIGIO, sig_io);
> +
> + /* Make a hang... */
> + hang = igt_hang_ctx_with_ahnd(device, ahnd, ctx->id, e->flags, 0);
> +
> + igt_post_hang_ring(device, hang);
> + put_ahnd(ahnd);
> +
> + igt_stop_hang_detector();
> +
> + /* Did it work? */
> + igt_assert(hang_count == 1);
> +}
> +
> /* This test covers the case where we end up in an uninitialised area of the
> * ppgtt and keep executing through it. This is particularly relevant if 48b
> * ppgtt is enabled because the ppgtt is massively bigger compared to the 32b
> @@ -408,6 +441,16 @@ igt_main
> igt_subtest("hangcheck-unterminated")
> hangcheck_unterminated(ctx);
>
> + igt_describe("Check that hang detector works");
> + igt_subtest_with_dynamic("detector") {
> + const struct intel_execution_engine2 *e;
> +
> + for_each_ctx_engine(device, ctx, e) {
> + igt_dynamic_f("%s", e->name)
> + test_hang_detector(ctx, e);
> + }
> + }
> +
> do_tests("GT", "gt", ctx);
>
> igt_fixture {
> --
> 2.25.1
>
