Hi,
On 14/01/2025 09:00, Krzysztof Karas wrote:
spin_unlock() function enables irqs regardless of their state
It doesn't, you confuse spin_unlock with spin_unlock_irq.
before spin_lock() was called. This might result in an interrupt
while holding a lock further down in the execution, as seen in
GitLab issue #13399.
Try to remedy the problem by saving irq state before spin lock
acquisition.
Please check guc_lrc_desc_unpin(). It gets called from the
destroyed_worker_func as hinted by lockdep in 13399. There is a plain
spin_lock() in there (in contradiction with itself). Fixing that one may
be all that is needed to fix this correctly.
If that turns out right then also:
Fixes: 2f2cc53b5fe7 ("drm/i915/guc: Close deregister-context race
against CT-loss")
Cc: <stable@xxxxxxxxxxxxxxx> # v6.9+
Regards,
Tvrtko
v2: add irqs' state save/restore calls to all locks/unlocks in
signal_irq_work() execution (Maciej)
Signed-off-by: Krzysztof Karas <krzysztof.karas@xxxxxxxxx>
---
This issue is hit rarely on CI and I was not able to reproduce
it locally. There might be more places where we should save and
restore irq state, so I am not adding "Closes" label for the
issue yet.
drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 21 ++++++++++++-------
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 5 +++--
2 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index cc866773ba6f..dd5542726b41 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -53,13 +53,15 @@ static void __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b)
static void intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b)
{
+ unsigned long flags;
+
if (!b->irq_engine)
return;
- spin_lock(&b->irq_lock);
+ spin_lock_irqsave(&b->irq_lock, flags);
if (!b->irq_armed)
__intel_breadcrumbs_arm_irq(b);
- spin_unlock(&b->irq_lock);
+ spin_unlock_irqrestore(&b->irq_lock, flags);
}
static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)
@@ -76,10 +78,12 @@ static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)
static void intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)
{
- spin_lock(&b->irq_lock);
+ unsigned long flags;
+
+ spin_lock_irqsave(&b->irq_lock, flags);
if (b->irq_armed)
__intel_breadcrumbs_disarm_irq(b);
- spin_unlock(&b->irq_lock);
+ spin_unlock_irqrestore(&b->irq_lock, flags);
}
static void add_signaling_context(struct intel_breadcrumbs *b,
@@ -173,6 +177,7 @@ static void signal_irq_work(struct irq_work *work)
const ktime_t timestamp = ktime_get();
struct llist_node *signal, *sn;
struct intel_context *ce;
+ unsigned long flags;
signal = NULL;
if (unlikely(!llist_empty(&b->signaled_requests)))
@@ -226,10 +231,10 @@ static void signal_irq_work(struct irq_work *work)
* spinlock as the callback chain may end up adding
* more signalers to the same context or engine.
*/
- spin_lock(&ce->signal_lock);
+ spin_lock_irqsave(&ce->signal_lock, flags);
list_del_rcu(&rq->signal_link);
release = remove_signaling_context(b, ce);
- spin_unlock(&ce->signal_lock);
+ spin_unlock_irqrestore(&ce->signal_lock, flags);
if (release) {
if (intel_timeline_is_last(ce->timeline, rq))
add_retire(b, ce->timeline);
@@ -254,11 +259,11 @@ static void signal_irq_work(struct irq_work *work)
if (rq->engine->sched_engine->retire_inflight_request_prio)
rq->engine->sched_engine->retire_inflight_request_prio(rq);
- spin_lock(&rq->lock);
+ spin_lock_irqsave(&rq->lock, flags);
list_replace(&rq->fence.cb_list, &cb_list);
__dma_fence_signal__timestamp(&rq->fence, timestamp);
__dma_fence_signal__notify(&rq->fence, &cb_list);
- spin_unlock(&rq->lock);
+ spin_unlock_irqrestore(&rq->lock, flags);
i915_request_put(rq);
}
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index 12f1ba7ca9c1..e9102f7246f5 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -4338,10 +4338,11 @@ static void guc_bump_inflight_request_prio(struct i915_request *rq,
static void guc_retire_inflight_request_prio(struct i915_request *rq)
{
struct intel_context *ce = request_to_scheduling_context(rq);
+ unsigned long flags;
- spin_lock(&ce->guc_state.lock);
+ spin_lock_irqsave(&ce->guc_state.lock, flags);
guc_prio_fini(rq, ce);
- spin_unlock(&ce->guc_state.lock);
+ spin_unlock_irqrestore(&ce->guc_state.lock, flags);
}
static void sanitize_hwsp(struct intel_engine_cs *engine)
