mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-15 23:25:07 +00:00
Code Issues Releases Wiki Activity

dma-buf/sw_sync: Synchronize signal vs syncpt free

Browse source 
[ Upstream commit d3c6dd1fb3 ]

During release of the syncpt, we remove it from the list of syncpt and
the tree, but only if it is not already been removed. However, during
signaling, we first remove the syncpt from the list. So, if we
concurrently free and signal the syncpt, the free may decide that it is
not part of the tree and immediately free itself -- meanwhile the
signaler goes on to use the now freed datastructure.

In particular, we get struck by commit 0e2f733add ("dma-buf: make
dma_fence structure a bit smaller v2") as the cb_list is immediately
clobbered by the kfree_rcu.

v2: Avoid calling into timeline_fence_release() from under the spinlock

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111381
Fixes: d3862e44da ("dma-buf/sw-sync: Fix locking around sync_timeline lists")
References: 0e2f733add ("dma-buf: make dma_fence structure a bit smaller v2")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: <stable@vger.kernel.org> # v4.14+
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190812154247.20508-1-chris@chris-wilson.co.uk
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Chris Wilson 2019-08-12 16:42:47 +01:00 committed by Greg Kroah-Hartman
parent c76e18970d
commit 81fbd2327c
1 changed files with 7 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
drivers/dma-buf/sw_sync.c
View file

@ -141,17 +141,14 @@ static void timeline_fence_release(struct dma_fence *fence)
{
struct sync_pt *pt = dma_fence_to_sync_pt(fence);
struct sync_timeline *parent = dma_fence_parent(fence);
unsigned long flags;
spin_lock_irqsave(fence->lock, flags);
if (!list_empty(&pt->link)) {
unsigned long flags;
spin_lock_irqsave(fence->lock, flags);
if (!list_empty(&pt->link)) {
list_del(&pt->link);
rb_erase(&pt->node, &parent->pt_tree);
}
spin_unlock_irqrestore(fence->lock, flags);
list_del(&pt->link);
rb_erase(&pt->node, &parent->pt_tree);
}
spin_unlock_irqrestore(fence->lock, flags);
sync_timeline_put(parent);
dma_fence_free(fence);
@ -274,7 +271,8 @@ static struct sync_pt *sync_pt_create(struct sync_timeline *obj,
p = &parent->rb_left;
} else {
if (dma_fence_get_rcu(&other->base)) {
dma_fence_put(&pt->base);
sync_timeline_put(obj);
kfree(pt);
pt = other;
goto unlock;
}