tests/drv_hangman: test for acthd increasing through invalid VM space

The hangcheck logic will not flag an hang if acthd keeps increasing.
However, if a malformed batch jumps to an invalid offset in the ppgtt it
can potentially continue executing through the whole address space
without triggering the hangcheck mechanism.

This patch adds a test to simulate the issue. I've kept the test running
for more than 10 minutes before killing it on a BDW and no hang occurred.
I've sampled i915_hangcheck_info a few times during the run and got the
following:

Hangcheck active, fires in 468ms
render ring:
	seqno = fffff55e [current fffff55e]
	ACTHD = 0x47df685ecc [current 0x4926b81d90]
	max ACTHD = 0x47df685ecc
	score = 0
	action = 2
	instdone read = 0xffd7ffff 0xffffffff 0xffffffff 0xffffffff
	instdone accu = 0x00000000 0x00000000 0x00000000 0x00000000

Hangcheck active, fires in 424ms
render ring:
	seqno = fffff55e [current fffff55e]
	ACTHD = 0x6c953d3a34 [current 0x6de5e76fa4]
	max ACTHD = 0x6c953d3a34
	score = 0
	action = 2
	instdone read = 0xffd7ffff 0xffffffff 0xffffffff 0xffffffff
	instdone accu = 0x00000000 0x00000000 0x00000000 0x00000000

Hangcheck active, fires in 1692ms
render ring:
	seqno = fffff55e [current fffff55e]
	ACTHD = 0x1f49b0366dc [current 0x1f4dcbd88ec]
	max ACTHD = 0x1f49b0366dc
	score = 0
	action = 2
	instdone read = 0xffd7ffff 0xffffffff 0xffffffff 0xffffffff
	instdone accu = 0x00000000 0x00000000 0x00000000 0x00000000

v2: use the new gem_wait() function (Chris)

v3: switch to unterminated batch and rename test, remove redundant
    check, update test requirements (Chris), update top comment

v4: force gpu reset if the hang detection fails (Mika)

Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Arun Siluvery <arun.siluvery@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
[Mika: removed batch_len=8]
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
This commit is contained in:
Daniele Ceraolo Spurio 2016-03-01 11:01:33 +00:00 committed by Mika Kuoppala
parent 03c7f84eb1
commit 95ca7644db

View File

@ -284,6 +284,46 @@ static void test_error_state_capture(unsigned ring_id,
check_error_state(gen, cmd_parser, ring_name, offset);
}
/* 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
* case and it takes a lot more time to wrap, so the acthd can potentially keep
* increasing for a long time
*/
#define NSEC_PER_SEC 1000000000L
static void hangcheck_unterminated(void)
{
int fd;
/* timeout needs to be greater than ~5*hangcheck */
int64_t timeout_ns = 100 * NSEC_PER_SEC; /* 100 seconds */
struct drm_i915_gem_execbuffer2 execbuf;
struct drm_i915_gem_exec_object2 gem_exec;
uint32_t handle;
fd = drm_open_driver(DRIVER_INTEL);
igt_require(gem_uses_full_ppgtt(fd));
igt_require_hang_ring(fd, 0);
handle = gem_create(fd, 4096);
memset(&gem_exec, 0, sizeof(gem_exec));
gem_exec.handle = handle;
memset(&execbuf, 0, sizeof(execbuf));
execbuf.buffers_ptr = (uintptr_t)&gem_exec;
execbuf.buffer_count = 1;
gem_execbuf(fd, &execbuf);
if (gem_wait(fd, handle, &timeout_ns) != 0) {
/* need to manually trigger an hang to clean before failing */
igt_force_gpu_reset();
igt_assert_f(0, "unterminated batch did not trigger an hang!");
}
close(fd);
}
igt_main
{
const struct intel_execution_engine *e;
@ -310,4 +350,7 @@ igt_main
test_error_state_capture(e->exec_id | e->flags,
e->full_name);
}
igt_subtest("hangcheck-unterminated")
hangcheck_unterminated();
}