From: Chris Wilson <chris@chris-wilson.co.uk> To: intel-gfx@lists.freedesktop.org Subject: [PATCH 08/28] drm/i915/gem: Safely acquire the ctx->vm when copying Date: Thu, 7 Nov 2019 08:12:32 +0000 [thread overview] Message-ID: <20191107081252.10542-8-chris@chris-wilson.co.uk> (raw) In-Reply-To: <20191107081252.10542-1-chris@chris-wilson.co.uk> As we read the ctx->vm unlocked before cloning/exporting, we should validate our reference is correct before returning it. We already do for clone_vm() but were not so strict around get_ppgtt(). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 80 +++++++++++---------- 1 file changed, 43 insertions(+), 37 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index d49869b1aa10..774d71b1ea9b 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -995,6 +995,38 @@ static int context_barrier_task(struct i915_gem_context *ctx, return err; } +static struct i915_address_space * +context_get_vm_rcu(struct i915_gem_context *ctx) +{ + do { + struct i915_address_space *vm; + + vm = rcu_dereference(ctx->vm); + if (!kref_get_unless_zero(&vm->ref)) + continue; + + /* + * This ppgtt may have be reallocated between + * the read and the kref, and reassigned to a third + * context. In order to avoid inadvertent sharing + * of this ppgtt with that third context (and not + * src), we have to confirm that we have the same + * ppgtt after passing through the strong memory + * barrier implied by a successful + * kref_get_unless_zero(). + * + * Once we have acquired the current ppgtt of src, + * we no longer care if it is released from src, as + * it cannot be reallocated elsewhere. + */ + + if (vm == rcu_access_pointer(ctx->vm)) + return rcu_pointer_handoff(vm); + + i915_vm_put(vm); + } while (1); +} + static int get_ppgtt(struct drm_i915_file_private *file_priv, struct i915_gem_context *ctx, struct drm_i915_gem_context_param *args) @@ -1006,7 +1038,7 @@ static int get_ppgtt(struct drm_i915_file_private *file_priv, return -ENODEV; rcu_read_lock(); - vm = i915_vm_get(ctx->vm); + vm = context_get_vm_rcu(ctx); rcu_read_unlock(); ret = mutex_lock_interruptible(&file_priv->vm_idr_lock); @@ -2035,47 +2067,21 @@ static int clone_vm(struct i915_gem_context *dst, struct i915_address_space *vm; int err = 0; - rcu_read_lock(); - do { - vm = rcu_dereference(src->vm); - if (!vm) - break; - - if (!kref_get_unless_zero(&vm->ref)) - continue; - - /* - * This ppgtt may have be reallocated between - * the read and the kref, and reassigned to a third - * context. In order to avoid inadvertent sharing - * of this ppgtt with that third context (and not - * src), we have to confirm that we have the same - * ppgtt after passing through the strong memory - * barrier implied by a successful - * kref_get_unless_zero(). - * - * Once we have acquired the current ppgtt of src, - * we no longer care if it is released from src, as - * it cannot be reallocated elsewhere. - */ - - if (vm == rcu_access_pointer(src->vm)) - break; + if (!rcu_access_pointer(src->vm)) + return 0; - i915_vm_put(vm); - } while (1); + rcu_read_lock(); + vm = context_get_vm_rcu(src); rcu_read_unlock(); - if (vm) { - if (!mutex_lock_interruptible(&dst->mutex)) { - __assign_ppgtt(dst, vm); - mutex_unlock(&dst->mutex); - } else { - err = -EINTR; - } - i915_vm_put(vm); + if (!mutex_lock_interruptible(&dst->mutex)) { + __assign_ppgtt(dst, vm); + mutex_unlock(&dst->mutex); + } else { + err = -EINTR; } + i915_vm_put(vm); return err; } -- 2.24.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
WARNING: multiple messages have this Message-ID (diff)
From: Chris Wilson <chris@chris-wilson.co.uk> To: intel-gfx@lists.freedesktop.org Subject: [Intel-gfx] [PATCH 08/28] drm/i915/gem: Safely acquire the ctx->vm when copying Date: Thu, 7 Nov 2019 08:12:32 +0000 [thread overview] Message-ID: <20191107081252.10542-8-chris@chris-wilson.co.uk> (raw) Message-ID: <20191107081232.TUu5g2IF3tyOBlVy1tlQMUBEaVPl6WoPhXI3CmfziXY@z> (raw) In-Reply-To: <20191107081252.10542-1-chris@chris-wilson.co.uk> As we read the ctx->vm unlocked before cloning/exporting, we should validate our reference is correct before returning it. We already do for clone_vm() but were not so strict around get_ppgtt(). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 80 +++++++++++---------- 1 file changed, 43 insertions(+), 37 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index d49869b1aa10..774d71b1ea9b 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -995,6 +995,38 @@ static int context_barrier_task(struct i915_gem_context *ctx, return err; } +static struct i915_address_space * +context_get_vm_rcu(struct i915_gem_context *ctx) +{ + do { + struct i915_address_space *vm; + + vm = rcu_dereference(ctx->vm); + if (!kref_get_unless_zero(&vm->ref)) + continue; + + /* + * This ppgtt may have be reallocated between + * the read and the kref, and reassigned to a third + * context. In order to avoid inadvertent sharing + * of this ppgtt with that third context (and not + * src), we have to confirm that we have the same + * ppgtt after passing through the strong memory + * barrier implied by a successful + * kref_get_unless_zero(). + * + * Once we have acquired the current ppgtt of src, + * we no longer care if it is released from src, as + * it cannot be reallocated elsewhere. + */ + + if (vm == rcu_access_pointer(ctx->vm)) + return rcu_pointer_handoff(vm); + + i915_vm_put(vm); + } while (1); +} + static int get_ppgtt(struct drm_i915_file_private *file_priv, struct i915_gem_context *ctx, struct drm_i915_gem_context_param *args) @@ -1006,7 +1038,7 @@ static int get_ppgtt(struct drm_i915_file_private *file_priv, return -ENODEV; rcu_read_lock(); - vm = i915_vm_get(ctx->vm); + vm = context_get_vm_rcu(ctx); rcu_read_unlock(); ret = mutex_lock_interruptible(&file_priv->vm_idr_lock); @@ -2035,47 +2067,21 @@ static int clone_vm(struct i915_gem_context *dst, struct i915_address_space *vm; int err = 0; - rcu_read_lock(); - do { - vm = rcu_dereference(src->vm); - if (!vm) - break; - - if (!kref_get_unless_zero(&vm->ref)) - continue; - - /* - * This ppgtt may have be reallocated between - * the read and the kref, and reassigned to a third - * context. In order to avoid inadvertent sharing - * of this ppgtt with that third context (and not - * src), we have to confirm that we have the same - * ppgtt after passing through the strong memory - * barrier implied by a successful - * kref_get_unless_zero(). - * - * Once we have acquired the current ppgtt of src, - * we no longer care if it is released from src, as - * it cannot be reallocated elsewhere. - */ - - if (vm == rcu_access_pointer(src->vm)) - break; + if (!rcu_access_pointer(src->vm)) + return 0; - i915_vm_put(vm); - } while (1); + rcu_read_lock(); + vm = context_get_vm_rcu(src); rcu_read_unlock(); - if (vm) { - if (!mutex_lock_interruptible(&dst->mutex)) { - __assign_ppgtt(dst, vm); - mutex_unlock(&dst->mutex); - } else { - err = -EINTR; - } - i915_vm_put(vm); + if (!mutex_lock_interruptible(&dst->mutex)) { + __assign_ppgtt(dst, vm); + mutex_unlock(&dst->mutex); + } else { + err = -EINTR; } + i915_vm_put(vm); return err; } -- 2.24.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2019-11-07 8:13 UTC|newest] Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-07 8:12 [PATCH 01/28] drm/i915: Leave the aliasing-ppgtt size alone Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 02/28] drm: Move EXPORT_SYMBOL_FOR_TESTS_ONLY under a separate Kconfig Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 03/28] drm: Expose a method for creating anonymous struct file around drm_minor Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 04/28] drm/i915/selftests: Replace mock_file hackery with drm's true fake Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 05/28] drm/i915/selftests: Wrap vm_mmap() around GEM objects Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 06/28] drm/i915/selftests: Verify mmap_gtt revocation on unbinding Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 07/28] drm/i915/userptr: Try to acquire the page lock around set_page_dirty() Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` Chris Wilson [this message] 2019-11-07 8:12 ` [Intel-gfx] [PATCH 08/28] drm/i915/gem: Safely acquire the ctx->vm when copying Chris Wilson 2019-11-07 8:12 ` [PATCH 09/28] drm/i915/selftests: Exercise parallel blit operations on a single ctx Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 10/28] drm/i915/selftests: Perform some basic cycle counting of MI ops Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:39 ` Mika Kuoppala 2019-11-07 8:39 ` [Intel-gfx] " Mika Kuoppala 2019-11-07 8:47 ` Chris Wilson 2019-11-07 8:47 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 11/28] drm/i915/selftests: Mock the engine sorting for easy validation Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 12/28] drm/i915: Use a ctor for TYPESAFE_BY_RCU i915_request Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 13/28] drm/i915: Drop GEM context as a direct link from i915_request Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 14/28] drm/i915: Push the use-semaphore marker onto the intel_context Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 15/28] drm/i915: Remove i915->kernel_context Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 16/28] drm/i915: Move i915_gem_init_contexts() earlier Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 17/28] drm/i915/gt: Defer engine registration until fully initialised Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 12:22 ` Mika Kuoppala 2019-11-07 12:22 ` [Intel-gfx] " Mika Kuoppala 2019-11-07 8:12 ` [PATCH 18/28] drm/i915/gt: Pull GT initialisation under intel_gt_init() Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 19/28] drm/i915/gt: Merge engine init/setup loops Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 20/28] drm/i915/gt: Expose engine properties via sysfs Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 21/28] drm/i915/gt: Expose engine->mmio_base " Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 22/28] drm/i915/gt: Expose timeslice duration to sysfs Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 23/28] drm/i915/gt: Expose reset stop timeout via sysfs Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 24/28] drm/i915/gt: Expose preempt reset " Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 25/28] drm/i915/gt: Expose heartbeat interval " Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 26/28] drm/i915: Flush idle barriers when waiting Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 27/28] drm/i915: Allow userspace to specify ringsize on construction Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 8:12 ` [PATCH 28/28] drm/i915/gem: Honour O_NONBLOCK before throttling execbuf submissions Chris Wilson 2019-11-07 8:12 ` [Intel-gfx] " Chris Wilson 2019-11-07 11:18 ` ✗ Fi.CI.CHECKPATCH: warning for series starting with [01/28] drm/i915: Leave the aliasing-ppgtt size alone Patchwork 2019-11-07 11:18 ` [Intel-gfx] " Patchwork 2019-11-07 11:30 ` ✗ Fi.CI.SPARSE: " Patchwork 2019-11-07 11:30 ` [Intel-gfx] " Patchwork 2019-11-07 11:39 ` ✗ Fi.CI.BAT: failure " Patchwork 2019-11-07 11:39 ` [Intel-gfx] " Patchwork
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