Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > 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@xxxxxxxxxxxxxxxxxx> > Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > Cc: Andi Shyti <andi.shyti@xxxxxxxxx> Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/i915_gpu_error.c | 18 ++++++++++++------ > drivers/gpu/drm/i915/i915_gpu_error.h | 1 - > 2 files changed, 12 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c > index 424ad975a360..6dd2fc0b0d47 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, > @@ -1204,16 +1204,18 @@ static void engine_record_registers(struct intel_engine_coredump *ee) > } > } > > -static void record_request(const struct i915_request *request, > +static bool record_request(const struct i915_request *request, > struct i915_request_coredump *erq) > { > const struct i915_gem_context *ctx; > > + if (i915_request_completed(request)) > + return false; > + > erq->flags = request->fence.flags; > 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; > > @@ -1223,6 +1225,8 @@ static void record_request(const struct i915_request *request, > if (ctx) > erq->pid = pid_nr(ctx->pid); > rcu_read_unlock(); > + > + return true; > } > > static void engine_record_execlists(struct intel_engine_coredump *ee) > @@ -1231,8 +1235,10 @@ static void engine_record_execlists(struct intel_engine_coredump *ee) > struct i915_request * const *port = el->active; > unsigned int n = 0; > > - while (*port) > - record_request(*port++, &ee->execlist[n++]); > + while (*port) { > + if (record_request(*port++, &ee->execlist[n])) > + n++; > + } > > ee->num_ports = n; > } > diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h > index 0d1f6c8ff355..fa2d82a6de04 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; > -- > 2.20.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
