In intel_gt_wait_for_idle, we use the remaining timeout returned from intel_gt_retire_requests_timeout to wait on the GuC being idle. However, the returned variable can have a negative value if something goes wrong during the wait, leading to us hitting a GEM_BUG_ON in the GuC wait function. To fix this, make sure to only return the timeout if it is positive.
Fixes: b97060a99b01b ("drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC") Signed-off-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Cc: Matthew Brost matthew.brost@intel.com Cc: John Harrison john.c.harrison@intel.com --- drivers/gpu/drm/i915/gt/intel_gt_requests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c index edb881d756309..ef70c209976d8 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c @@ -197,7 +197,7 @@ out_active: spin_lock(&timelines->lock); active_count++;
if (remaining_timeout) - *remaining_timeout = timeout; + *remaining_timeout = timeout > 0 ? timeout : 0;
return active_count ? timeout : 0; }
On Fri, Mar 25, 2022 at 10:58:39AM -0700, Daniele Ceraolo Spurio wrote:
In intel_gt_wait_for_idle, we use the remaining timeout returned from intel_gt_retire_requests_timeout to wait on the GuC being idle. However, the returned variable can have a negative value if something goes wrong during the wait, leading to us hitting a GEM_BUG_ON in the GuC wait function. To fix this, make sure to only return the timeout if it is positive.
Fixes: b97060a99b01b ("drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC") Signed-off-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Cc: Matthew Brost matthew.brost@intel.com Cc: John Harrison john.c.harrison@intel.com
Reviewed-by: Matthew Brost matthew.brost@intel.com
drivers/gpu/drm/i915/gt/intel_gt_requests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c index edb881d756309..ef70c209976d8 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c @@ -197,7 +197,7 @@ out_active: spin_lock(&timelines->lock); active_count++;
if (remaining_timeout)
*remaining_timeout = timeout;
*remaining_timeout = timeout > 0 ? timeout : 0;return active_count ? timeout : 0;
}
2.25.1
On 3/25/2022 6:58 PM, Daniele Ceraolo Spurio wrote:
In intel_gt_wait_for_idle, we use the remaining timeout returned from intel_gt_retire_requests_timeout to wait on the GuC being idle. However, the returned variable can have a negative value if something goes wrong during the wait, leading to us hitting a GEM_BUG_ON in the GuC wait function. To fix this, make sure to only return the timeout if it is positive.
Fixes: b97060a99b01b ("drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC") Signed-off-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Cc: Matthew Brost matthew.brost@intel.com Cc: John Harrison john.c.harrison@intel.com
drivers/gpu/drm/i915/gt/intel_gt_requests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c index edb881d756309..ef70c209976d8 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c @@ -197,7 +197,7 @@ out_active: spin_lock(&timelines->lock); active_count++;
if (remaining_timeout)
*remaining_timeout = timeout;
*remaining_timeout = timeout > 0 ? timeout : 0;
Should the last flush_submission() be "if ( timeout > 0 &&flush_submission(gt, timeout))" ?
Nirmoy
return active_count ? timeout : 0; }
On 3/25/2022 11:37 AM, Das, Nirmoy wrote:
On 3/25/2022 6:58 PM, Daniele Ceraolo Spurio wrote:
In intel_gt_wait_for_idle, we use the remaining timeout returned from intel_gt_retire_requests_timeout to wait on the GuC being idle. However, the returned variable can have a negative value if something goes wrong during the wait, leading to us hitting a GEM_BUG_ON in the GuC wait function. To fix this, make sure to only return the timeout if it is positive.
Fixes: b97060a99b01b ("drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC") Signed-off-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Cc: Matthew Brost matthew.brost@intel.com Cc: John Harrison john.c.harrison@intel.com
drivers/gpu/drm/i915/gt/intel_gt_requests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c index edb881d756309..ef70c209976d8 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c @@ -197,7 +197,7 @@ out_active: spin_lock(&timelines->lock); active_count++; if (remaining_timeout) - *remaining_timeout = timeout; + *remaining_timeout = timeout > 0 ? timeout : 0;
Should the last flush_submission() be "if ( timeout > 0 &&flush_submission(gt, timeout))" ?
I considered it, but flush_submission only checks for timeout != 0 so it won't accidentally make use of a negative value thinking it's positive. I don't know if the flush is purposely done even if timeout is negative or if that's a mistake, but that code has been there long before we modified the function to return the remaining timeout and never seems to have caused issues, so I decided not to change it.
Daniele
Nirmoy
return active_count ? timeout : 0; }
On 3/25/2022 9:33 PM, Ceraolo Spurio, Daniele wrote:
On 3/25/2022 11:37 AM, Das, Nirmoy wrote:
On 3/25/2022 6:58 PM, Daniele Ceraolo Spurio wrote:
In intel_gt_wait_for_idle, we use the remaining timeout returned from intel_gt_retire_requests_timeout to wait on the GuC being idle. However, the returned variable can have a negative value if something goes wrong during the wait, leading to us hitting a GEM_BUG_ON in the GuC wait function. To fix this, make sure to only return the timeout if it is positive.
Fixes: b97060a99b01b ("drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC") Signed-off-by: Daniele Ceraolo Spurio daniele.ceraolospurio@intel.com Cc: Matthew Brost matthew.brost@intel.com Cc: John Harrison john.c.harrison@intel.com
drivers/gpu/drm/i915/gt/intel_gt_requests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c index edb881d756309..ef70c209976d8 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c @@ -197,7 +197,7 @@ out_active: spin_lock(&timelines->lock); active_count++; if (remaining_timeout) - *remaining_timeout = timeout; + *remaining_timeout = timeout > 0 ? timeout : 0;
Should the last flush_submission() be "if ( timeout > 0 &&flush_submission(gt, timeout))" ?
I considered it, but flush_submission only checks for timeout != 0 so it won't accidentally make use of a negative value thinking it's positive. I don't know if the flush is purposely done even if timeout is negative or if that's a mistake, but that code has been there long before we modified the function to return the remaining timeout and never seems to have caused issues, so I decided not to change it.
Yes, we need clarify if we really need the final flush if the timeout is negative.
But this patch is Acked-by: Nirmoy Das nirmoy.das@intel.com
Nirmoy
Daniele
Nirmoy
return active_count ? timeout : 0; }
dri-devel@lists.freedesktop.org
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Ceraolo Spurio, Daniele -
Daniele Ceraolo Spurio
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Das, Nirmoy -
Matthew Brost