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authorThomas Hellstrom <unichrome@shipmail.org>2005-04-20 18:50:49 +0000
committerThomas Hellstrom <unichrome@shipmail.org>2005-04-20 18:50:49 +0000
commit699d4ad53a62e46344b672365dda0be4001edd99 (patch)
tree1ac0e9023041d9962ad16debe48afdc0f64935b3 /linux-core
parent2b8dc25dc549533f1567093fb7dffc06d6f55268 (diff)
A fix for a locking bug which is triggered when a client tries to lock with
flag DMA_QUIESCENT (typically the X server), but gets interrupted by a signal. The locking IOCTL should then return an error, but if DMA_QUIESCENT succeeds it returns 0, and the client falsely thinks it has the lock. In addition The client waits for DMA_QUISCENT and possibly DMA_READY without having the lock.
Diffstat (limited to 'linux-core')
-rw-r--r--linux-core/drm_lock.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/linux-core/drm_lock.c b/linux-core/drm_lock.c
index b9833724..048f084f 100644
--- a/linux-core/drm_lock.c
+++ b/linux-core/drm_lock.c
@@ -99,6 +99,9 @@ int drm_lock(struct inode *inode, struct file *filp,
current->state = TASK_RUNNING;
remove_wait_queue(&dev->lock.lock_queue, &entry);
+ DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" );
+ if (ret) return ret;
+
sigemptyset(&dev->sigmask);
sigaddset(&dev->sigmask, SIGSTOP);
sigaddset(&dev->sigmask, SIGTSTP);
@@ -111,8 +114,12 @@ int drm_lock(struct inode *inode, struct file *filp,
if (dev->driver->dma_ready && (lock.flags & _DRM_LOCK_READY))
dev->driver->dma_ready(dev);
- if (dev->driver->dma_quiescent && (lock.flags & _DRM_LOCK_QUIESCENT))
- return dev->driver->dma_quiescent(dev);
+ if (dev->driver->dma_quiescent && (lock.flags & _DRM_LOCK_QUIESCENT)) {
+ if (dev->driver->dma_quiescent(dev)) {
+ DRM_DEBUG( "%d waiting for DMA quiescent\n", lock.context);
+ return DRM_ERR(EBUSY);
+ }
+ }
if (dev->driver->kernel_context_switch
&& dev->last_context != lock.context) {
@@ -120,9 +127,7 @@ int drm_lock(struct inode *inode, struct file *filp,
lock.context);
}
- DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock");
-
- return ret;
+ return 0;
}
/**