From 2cf654db8d7eafb973d28eb3cddf043d353e1345 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 13 Dec 2017 09:48:02 +0000 Subject: [PATCH] drm/i915/fence: Use rcu to defer freeing of irq_work It is illegal to perform an immediate free of the struct irq_work from inside the irq_work callback (as irq_work_run_list modifies work->flags after execution of the work->func()). As we use the irq_work to coordinate the freeing of the callback from two different softirq paths, we need to defer the kfree from inside our irq_work callback, for which we can use kfree_rcu. Fixes: 81c0ed21aa91 ("drm/i915/fence: Avoid del_timer_sync() from inside a timer") Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Joonas Lahtinen Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20171213094802.28243-1-chris@chris-wilson.co.uk (cherry picked from commit 7d622351c94172a42bfe9b13bdb0fdc2be90ed3b) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/i915_sw_fence.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c index e8ca67a129d2..ac236b88c99c 100644 --- a/drivers/gpu/drm/i915/i915_sw_fence.c +++ b/drivers/gpu/drm/i915/i915_sw_fence.c @@ -367,6 +367,7 @@ struct i915_sw_dma_fence_cb { struct dma_fence *dma; struct timer_list timer; struct irq_work work; + struct rcu_head rcu; }; static void timer_i915_sw_fence_wake(struct timer_list *t) @@ -406,7 +407,7 @@ static void irq_i915_sw_fence_work(struct irq_work *wrk) del_timer_sync(&cb->timer); dma_fence_put(cb->dma); - kfree(cb); + kfree_rcu(cb, rcu); } int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence, -- 2.30.2