From: Daniel Vetter <daniel.vetter@ffwll.ch> To: DRI Development <dri-devel@lists.freedesktop.org> Cc: "Intel Graphics Development" <intel-gfx@lists.freedesktop.org>, "Daniel Vetter" <daniel.vetter@ffwll.ch>, "Daniel Vetter" <daniel.vetter@intel.com>, "Jason Ekstrand" <jason@jlekstrand.net>, "Chris Wilson" <chris@chris-wilson.co.uk>, "Tvrtko Ursulin" <tvrtko.ursulin@intel.com>, "Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>, "Matthew Brost" <matthew.brost@intel.com>, "Matthew Auld" <matthew.auld@intel.com>, "Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>, "Thomas Hellström" <thomas.hellstrom@intel.com>, "Lionel Landwerlin" <lionel.g.landwerlin@intel.com>, "Dave Airlie" <airlied@redhat.com> Subject: [PATCH 02/11] drm/i915: Release ctx->syncobj on final put, not on ctx close Date: Fri, 13 Aug 2021 22:30:24 +0200 [thread overview] Message-ID: <20210813203033.3179400-2-daniel.vetter@ffwll.ch> (raw) In-Reply-To: <20210813203033.3179400-1-daniel.vetter@ffwll.ch> gem context refcounting is another exercise in least locking design it seems, where most things get destroyed upon context closure (which can race with anything really). Only the actual memory allocation and the locks survive while holding a reference. This tripped up Jason when reimplementing the single timeline feature in commit 00dae4d3d35d4f526929633b76e00b0ab4d3970d Author: Jason Ekstrand <jason@jlekstrand.net> Date: Thu Jul 8 10:48:12 2021 -0500 drm/i915: Implement SINGLE_TIMELINE with a syncobj (v4) We could fix the bug by holding ctx->mutex in execbuf and clear the pointer (again while holding the mutex) context_close, but it's cleaner to just make the context object actually invariant over its _entire_ lifetime. This way any other ioctl that's potentially racing, but holding a full reference, can still rely on ctx->syncobj being an immutable pointer. Which without this change, is not the case. Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Fixes: 00dae4d3d35d ("drm/i915: Implement SINGLE_TIMELINE with a syncobj (v4)") Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: "Thomas Hellström" <thomas.hellstrom@intel.com> Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Cc: Dave Airlie <airlied@redhat.com> --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 051bc357ff65..5a053cf14948 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -994,6 +994,9 @@ static void i915_gem_context_release_work(struct work_struct *work) trace_i915_context_free(ctx); GEM_BUG_ON(!i915_gem_context_is_closed(ctx)); + if (ctx->syncobj) + drm_syncobj_put(ctx->syncobj); + mutex_destroy(&ctx->engines_mutex); mutex_destroy(&ctx->lut_mutex); @@ -1220,9 +1223,6 @@ static void context_close(struct i915_gem_context *ctx) if (vm) i915_vm_close(vm); - if (ctx->syncobj) - drm_syncobj_put(ctx->syncobj); - ctx->file_priv = ERR_PTR(-EBADF); /* -- 2.32.0
WARNING: multiple messages have this Message-ID (diff)
From: Daniel Vetter <daniel.vetter@ffwll.ch> To: DRI Development <dri-devel@lists.freedesktop.org> Cc: "Intel Graphics Development" <intel-gfx@lists.freedesktop.org>, "Daniel Vetter" <daniel.vetter@ffwll.ch>, "Daniel Vetter" <daniel.vetter@intel.com>, "Jason Ekstrand" <jason@jlekstrand.net>, "Chris Wilson" <chris@chris-wilson.co.uk>, "Tvrtko Ursulin" <tvrtko.ursulin@intel.com>, "Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>, "Matthew Brost" <matthew.brost@intel.com>, "Matthew Auld" <matthew.auld@intel.com>, "Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>, "Thomas Hellström" <thomas.hellstrom@intel.com>, "Lionel Landwerlin" <lionel.g.landwerlin@intel.com>, "Dave Airlie" <airlied@redhat.com> Subject: [Intel-gfx] [PATCH 02/11] drm/i915: Release ctx->syncobj on final put, not on ctx close Date: Fri, 13 Aug 2021 22:30:24 +0200 [thread overview] Message-ID: <20210813203033.3179400-2-daniel.vetter@ffwll.ch> (raw) In-Reply-To: <20210813203033.3179400-1-daniel.vetter@ffwll.ch> gem context refcounting is another exercise in least locking design it seems, where most things get destroyed upon context closure (which can race with anything really). Only the actual memory allocation and the locks survive while holding a reference. This tripped up Jason when reimplementing the single timeline feature in commit 00dae4d3d35d4f526929633b76e00b0ab4d3970d Author: Jason Ekstrand <jason@jlekstrand.net> Date: Thu Jul 8 10:48:12 2021 -0500 drm/i915: Implement SINGLE_TIMELINE with a syncobj (v4) We could fix the bug by holding ctx->mutex in execbuf and clear the pointer (again while holding the mutex) context_close, but it's cleaner to just make the context object actually invariant over its _entire_ lifetime. This way any other ioctl that's potentially racing, but holding a full reference, can still rely on ctx->syncobj being an immutable pointer. Which without this change, is not the case. Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Fixes: 00dae4d3d35d ("drm/i915: Implement SINGLE_TIMELINE with a syncobj (v4)") Cc: Jason Ekstrand <jason@jlekstrand.net> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: "Thomas Hellström" <thomas.hellstrom@intel.com> Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Cc: Dave Airlie <airlied@redhat.com> --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 051bc357ff65..5a053cf14948 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -994,6 +994,9 @@ static void i915_gem_context_release_work(struct work_struct *work) trace_i915_context_free(ctx); GEM_BUG_ON(!i915_gem_context_is_closed(ctx)); + if (ctx->syncobj) + drm_syncobj_put(ctx->syncobj); + mutex_destroy(&ctx->engines_mutex); mutex_destroy(&ctx->lut_mutex); @@ -1220,9 +1223,6 @@ static void context_close(struct i915_gem_context *ctx) if (vm) i915_vm_close(vm); - if (ctx->syncobj) - drm_syncobj_put(ctx->syncobj); - ctx->file_priv = ERR_PTR(-EBADF); /* -- 2.32.0
next prev parent reply other threads:[~2021-08-13 20:30 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-13 20:30 [PATCH 01/11] drm/i915: Release i915_gem_context from a worker Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` Daniel Vetter [this message] 2021-08-13 20:30 ` [Intel-gfx] [PATCH 02/11] drm/i915: Release ctx->syncobj on final put, not on ctx close Daniel Vetter 2021-08-13 20:30 ` [PATCH 03/11] drm/i915: Keep gem ctx->vm alive until the final put Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 04/11] drm/i915: Drop code to handle set-vm races from execbuf Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 05/11] drm/i915: Rename i915_gem_context_get_vm_rcu to i915_gem_context_get_eb_vm Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 06/11] drm/i915: Use i915_gem_context_get_eb_vm in ctx_getparam Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 07/11] drm/i915: Add i915_gem_context_is_full_ppgtt Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 08/11] drm/i915: Use i915_gem_context_get_eb_vm in intel_context_set_gem Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 09/11] drm/i915: Drop __rcu from gem_context->vm Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 10/11] drm/i915: use xa_lock/unlock for fpriv->vm_xa lookups Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-31 9:29 ` Maarten Lankhorst 2021-08-31 9:29 ` [Intel-gfx] " Maarten Lankhorst 2021-08-31 12:14 ` [PATCH] " Daniel Vetter 2021-08-31 12:14 ` [Intel-gfx] " Daniel Vetter 2021-08-13 20:30 ` [PATCH 11/11] drm/i915: Stop rcu support for i915_address_space Daniel Vetter 2021-08-13 20:30 ` [Intel-gfx] " Daniel Vetter 2021-08-13 21:48 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with [01/11] drm/i915: Release i915_gem_context from a worker Patchwork 2021-08-13 21:49 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork 2021-08-13 22:18 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork 2021-08-14 1:26 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork 2021-08-14 10:43 ` [PATCH] " Daniel Vetter 2021-08-14 10:43 ` [Intel-gfx] " Daniel Vetter 2021-08-31 9:38 ` Maarten Lankhorst 2021-08-31 9:38 ` [Intel-gfx] " Maarten Lankhorst 2021-08-31 12:16 ` Daniel Vetter 2021-08-31 12:16 ` [Intel-gfx] " Daniel Vetter 2021-08-31 15:14 ` Daniel Vetter 2021-08-31 15:14 ` [Intel-gfx] " Daniel Vetter 2021-09-02 10:04 ` Maarten Lankhorst 2021-09-02 10:04 ` Maarten Lankhorst 2021-08-14 10:55 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for series starting with drm/i915: Release i915_gem_context from a worker (rev2) Patchwork 2021-08-14 10:56 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork 2021-08-14 11:19 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork 2021-08-14 12:38 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork 2021-08-31 10:16 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with drm/i915: Release i915_gem_context from a worker (rev3) Patchwork 2021-08-31 12:18 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with drm/i915: Release i915_gem_context from a worker (rev4) Patchwork 2021-09-02 12:42 ` [Intel-gfx] [PATCH 01/11] drm/i915: Release i915_gem_context from a worker Tvrtko Ursulin 2021-09-02 15:05 ` Daniel Vetter 2021-09-02 16:20 ` Tvrtko Ursulin 2021-09-02 20:02 ` Daniel Vetter 2021-09-03 10:40 ` Tvrtko Ursulin 2021-09-02 14:20 Daniel Vetter 2021-09-02 14:20 ` [PATCH 02/11] drm/i915: Release ctx->syncobj on final put, not on ctx close Daniel Vetter
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