From: Chris Wilson Date: Thu, 28 Jun 2018 14:22:06 +0100 Subject: drm/i915: Show vma allocator stack when in doubt Git-commit: 10195b1e4411191a30456e3e60bc539531b17053 Patch-mainline: v4.19-rc1 References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166 At the moment, gem_exec_gttfill fails with a sporadic EBUSY due to us wanting to unbind a pinned batch. Let's dump who first bound that vma to see if that helps us identify who still unexpectedly has it pinned. v2: We cannot allocate inside the printer (as it may be on an fs-reclaim path), so hope for the best and build the string on the stack v3: stack depth of 16 routinely overflows a 512 character string, limit it to 12 to avoid unsightly truncation. Signed-off-by: Chris Wilson Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20180628132206.8329-1-chris@chris-wilson.co.uk Acked-by: Petr Tesarik --- drivers/gpu/drm/i915/i915_vma.c | 39 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 37 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -21,7 +21,7 @@ * IN THE SOFTWARE. * */ - + #include "i915_vma.h" #include "i915_drv.h" @@ -30,6 +30,39 @@ #include +#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && IS_ENABLED(CONFIG_DRM_DEBUG_MM) + +#include + +static void vma_print_allocator(struct i915_vma *vma, const char *reason) +{ + unsigned long entries[12]; + struct stack_trace trace = { + .entries = entries, + .max_entries = ARRAY_SIZE(entries), + }; + char buf[512]; + + if (!vma->node.stack) { + DRM_DEBUG_DRIVER("vma.node [%08llx + %08llx] %s: unknown owner\n", + vma->node.start, vma->node.size, reason); + return; + } + + depot_fetch_stack(vma->node.stack, &trace); + snprint_stack_trace(buf, sizeof(buf), &trace, 0); + DRM_DEBUG_DRIVER("vma.node [%08llx + %08llx] %s: inserted at %s\n", + vma->node.start, vma->node.size, reason, buf); +} + +#else + +static void vma_print_allocator(struct i915_vma *vma, const char *reason) +{ +} + +#endif + static void i915_vma_retire(struct i915_gem_active *active, struct i915_request *rq) { @@ -875,8 +908,10 @@ int i915_vma_unbind(struct i915_vma *vma } GEM_BUG_ON(i915_vma_is_active(vma)); - if (i915_vma_is_pinned(vma)) + if (i915_vma_is_pinned(vma)) { + vma_print_allocator(vma, "is pinned"); return -EBUSY; + } if (!drm_mm_node_allocated(&vma->node)) return 0;