diff options
| author | Erik Gilling | 2013-03-01 01:43:18 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2013-03-04 10:46:54 +0100 |
| commit | c679212dbfd060513e156133326122bf9f496579 (patch) | |
| tree | 45d7d131fb492e9ff268b36fed8f907b1771a7b8 /drivers/staging | |
| parent | staging: sync: Dump sync state on fence errors (diff) | |
| download | kernel-qcow2-linux-c679212dbfd060513e156133326122bf9f496579.tar.gz kernel-qcow2-linux-c679212dbfd060513e156133326122bf9f496579.tar.xz kernel-qcow2-linux-c679212dbfd060513e156133326122bf9f496579.zip | |
staging: sync: Protect unlocked access to fence status
Fence status is checked outside of locks in both sync_fence_wait and
sync_fence_poll. This patch adds propper barrier protection in these
cases to avoid seeing stale status.
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Erik Gilling <konkers@android.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <robclark@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Erik Gilling <konkers@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
| -rw-r--r-- | drivers/staging/android/sync.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c index 36ffa2024875..2394189c5958 100644 --- a/drivers/staging/android/sync.c +++ b/drivers/staging/android/sync.c @@ -556,6 +556,16 @@ int sync_fence_cancel_async(struct sync_fence *fence, } EXPORT_SYMBOL(sync_fence_cancel_async); +static bool sync_fence_check(struct sync_fence *fence) +{ + /* + * Make sure that reads to fence->status are ordered with the + * wait queue event triggering + */ + smp_rmb(); + return fence->status != 0; +} + int sync_fence_wait(struct sync_fence *fence, long timeout) { int err = 0; @@ -563,7 +573,7 @@ int sync_fence_wait(struct sync_fence *fence, long timeout) if (timeout > 0) { timeout = msecs_to_jiffies(timeout); err = wait_event_interruptible_timeout(fence->wq, - fence->status != 0, + sync_fence_check(fence), timeout); } else if (timeout < 0) { err = wait_event_interruptible(fence->wq, fence->status != 0); @@ -630,6 +640,12 @@ static unsigned int sync_fence_poll(struct file *file, poll_table *wait) poll_wait(file, &fence->wq, wait); + /* + * Make sure that reads to fence->status are ordered with the + * wait queue event triggering + */ + smp_rmb(); + if (fence->status == 1) return POLLIN; else if (fence->status < 0) |