drm/i915: Drop rq->ring->vma peeking from error capture (9669a507) · Commits · 戴 / test

We only hold the active spinlock while dumping the error state, and this does not prevent another thread from retiring the request -- as it is quite possible that despite us capturing the current state, the GPU has completed the request. As such, it is dangerous to dereference state below the request as it may already be freed, and the simplest way to avoid the danger is not include it in the error state. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1788 Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Andi Shyti <andi.shyti@intel.com> Reviewed-by:

Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200424191410.27570-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gpu_error.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -467,14 +467,14 @@ static void error_print_request(struct drm_i915_error_state_buf *m,
		if (!erq->seqno)
		return;

		err_printf(m, "%s pid %d, seqno %8x:%08x%s%s, prio %d, start %08x, head %08x, tail %08x\n",
		err_printf(m, "%s pid %d, seqno %8x:%08x%s%s, prio %d, head %08x, tail %08x\n",
		prefix, erq->pid, erq->context, erq->seqno,
		test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
		&erq->flags) ? "!" : "",
		test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
		&erq->flags) ? "+" : "",
		erq->sched_attr.priority,
		erq->start, erq->head, erq->tail);
		erq->head, erq->tail);
		}

		static void error_print_context(struct drm_i915_error_state_buf *m,
		@@ -1213,7 +1213,6 @@ static void record_request(const struct i915_request *request,
		erq->context = request->fence.context;
		erq->seqno = request->fence.seqno;
		erq->sched_attr = request->sched.attr;
		erq->start = i915_ggtt_offset(request->ring->vma);
		erq->head = request->head;
		erq->tail = request->tail;

drivers/gpu/drm/i915/i915_gpu_error.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -50,7 +50,6 @@ struct i915_request_coredump {
		pid_t pid;
		u32 context;
		u32 seqno;
		u32 start;
		u32 head;
		u32 tail;
		struct i915_sched_attr sched_attr;

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