From 663a50ceac75c2208d2ad95365bc8382fd42f44d Mon Sep 17 00:00:00 2001 From: Yan Zhao Date: Wed, 27 Mar 2019 00:55:45 -0400 Subject: drm/i915/gvt: do not let pin count of shadow mm go negative shadow mm's pin count got increased in workload preparation phase, which is after workload scanning. it will get decreased in complete_current_workload() anyway after workload completion. Sometimes, if a workload meets a scanning error, its shadow mm pin count will not get increased but will get decreased in the end. This patch lets shadow mm's pin count not go below 0. Fixes: 2707e4446688 ("drm/i915/gvt: vGPU graphics memory virtualization") Cc: zhenyuw@linux.intel.com Cc: stable@vger.kernel.org #4.14+ Signed-off-by: Yan Zhao Signed-off-by: Zhenyu Wang --- drivers/gpu/drm/i915/gvt/gtt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/gpu/drm/i915/gvt/gtt.c') diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c index d7052ab7908c..cf133ef03873 100644 --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -1946,7 +1946,7 @@ void _intel_vgpu_mm_release(struct kref *mm_ref) */ void intel_vgpu_unpin_mm(struct intel_vgpu_mm *mm) { - atomic_dec(&mm->pincount); + atomic_dec_if_positive(&mm->pincount); } /** -- cgit v1.2.3-55-g7522 From 968a85b19d0a79dd8ed85f39e23eacd34b503e72 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 4 Apr 2019 08:30:56 +0100 Subject: drm/i915/gvt: Prevent use-after-free in ppgtt_free_all_spt() ppgtt_free_all_spt() iterates the radixtree as it is deleting it, forgoing all protection against the leaves being freed in the process (leaving the iter pointing into the void). A minimal fix seems to be to use the available post_shadow_list to decompose the tree into a list prior to destroying the radixtree. Alerted by the sparse warnings: drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in assignment (different address spaces) drivers/gpu/drm/i915/gvt/gtt.c:757:9: expected void **slot drivers/gpu/drm/i915/gvt/gtt.c:757:9: got void [noderef] ** drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in assignment (different address spaces) drivers/gpu/drm/i915/gvt/gtt.c:757:9: expected void **slot drivers/gpu/drm/i915/gvt/gtt.c:757:9: got void [noderef] ** drivers/gpu/drm/i915/gvt/gtt.c:758:45: warning: incorrect type in argument 1 (different address spaces) drivers/gpu/drm/i915/gvt/gtt.c:758:45: expected void [noderef] **slot drivers/gpu/drm/i915/gvt/gtt.c:758:45: got void **slot drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in argument 1 (different address spaces) drivers/gpu/drm/i915/gvt/gtt.c:757:9: expected void [noderef] **slot drivers/gpu/drm/i915/gvt/gtt.c:757:9: got void **slot drivers/gpu/drm/i915/gvt/gtt.c:757:9: warning: incorrect type in assignment (different address spaces) drivers/gpu/drm/i915/gvt/gtt.c:757:9: expected void **slot drivers/gpu/drm/i915/gvt/gtt.c:757:9: got void [noderef] ** This would also have been loudly warning if run through CI for the invalid RCU dereferences. Fixes: b6c126a39345 ("drm/i915/gvt: Manage shadow pages with radix tree") Reviewed-by: Zhenyu Wang Signed-off-by: Chris Wilson Cc: Changbin Du Cc: Zhenyu Wang Cc: Zhi Wang Signed-off-by: Zhenyu Wang --- drivers/gpu/drm/i915/gvt/gtt.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/i915/gvt/gtt.c') diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c index cf133ef03873..9814773882ec 100644 --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -750,14 +750,20 @@ static void ppgtt_free_spt(struct intel_vgpu_ppgtt_spt *spt) static void ppgtt_free_all_spt(struct intel_vgpu *vgpu) { - struct intel_vgpu_ppgtt_spt *spt; + struct intel_vgpu_ppgtt_spt *spt, *spn; struct radix_tree_iter iter; - void **slot; + LIST_HEAD(all_spt); + void __rcu **slot; + rcu_read_lock(); radix_tree_for_each_slot(slot, &vgpu->gtt.spt_tree, &iter, 0) { spt = radix_tree_deref_slot(slot); - ppgtt_free_spt(spt); + list_move(&spt->post_shadow_list, &all_spt); } + rcu_read_unlock(); + + list_for_each_entry_safe(spt, spn, &all_spt, post_shadow_list) + ppgtt_free_spt(spt); } static int ppgtt_handle_guest_write_page_table_bytes( -- cgit v1.2.3-55-g7522