From accd6321028b45d4bb1cc2eb23b21b456c24de43 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 24 Apr 2020 20:14:10 +0100 Subject: [PATCH] drm/i915: Drop rq->ring->vma peeking from error capture 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 Cc: Mika Kuoppala Cc: Andi Shyti Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20200424191410.27570-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gpu_error.c | 5 ++--- drivers/gpu/drm/i915/i915_gpu_error.h | 1 - 2 files changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c index 424ad975a3608..4d54dba353027 100644 --- a/drivers/gpu/drm/i915/i915_gpu_error.c +++ b/drivers/gpu/drm/i915/i915_gpu_error.c @@ -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; diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h index 0d1f6c8ff3556..fa2d82a6de04b 100644 --- a/drivers/gpu/drm/i915/i915_gpu_error.h +++ b/drivers/gpu/drm/i915/i915_gpu_error.h @@ -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; -- 2.39.5