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gpu: ion: Fix race between ion_import and ion_free 

If preemted during ion_free after the refcount is updated but
before the handle can be removed from the rb_tree, import
might find that handle in the tree and try to reuse it
when execution returns to free, the handle will be cleaned
up leaving the caller of import with a corrupt handle.
This patch modifies the locking to protect agains this race.

Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
wifi-calibration
Rebecca Schultz Zavin 2013-12-13 14:24:01 -08:00 committed by Greg Kroah-Hartman
parent 12edf53db3
commit 0e9c03a58e
1 changed files with 1 additions and 4 deletions
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5
drivers/staging/android/ion/ion.c
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@ -253,8 +253,6 @@ static void ion_handle_destroy(struct kref *kref)
struct ion_client *client = handle->client;
struct ion_buffer *buffer = handle->buffer;
mutex_lock(&client->lock);
mutex_lock(&buffer->lock);
while (handle->kmap_cnt)
ion_handle_kmap_put(handle);
@ -262,7 +260,6 @@ static void ion_handle_destroy(struct kref *kref)
if (!RB_EMPTY_NODE(&handle->node))
rb_erase(&handle->node, &client->handles);
mutex_unlock(&client->lock);
ion_buffer_put(buffer);
kfree(handle);
@ -406,13 +403,13 @@ void ion_free(struct ion_client *client, struct ion_handle *handle)
mutex_lock(&client->lock);
valid_handle = ion_handle_validate(client, handle);
mutex_unlock(&client->lock);
if (!valid_handle) {
WARN(1, "%s: invalid handle passed to free.\n", __func__);
return;
}
ion_handle_put(handle);
mutex_unlock(&client->lock);
}
EXPORT_SYMBOL(ion_free);