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ion:synchronize debugfs callback and ion_client_destroy 

There are race condition B/T ion_client_destroy and debugfs callbacks.
Let's use a mutex to synchronize them.

Signed-off-by: Neil Zhang <neilzhang1123@hotmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Neil Zhang 2016-01-26 17:39:06 +08:00 committed by Greg Kroah-Hartman
parent 9f90381b3e
commit 948c4db4ee
1 changed files with 44 additions and 0 deletions
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44
drivers/staging/android/ion/ion.c
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@ -677,6 +677,34 @@ void ion_unmap_kernel(struct ion_client *client, struct ion_handle *handle)
}
EXPORT_SYMBOL(ion_unmap_kernel);
static struct mutex debugfs_mutex;
static struct rb_root *ion_root_client;
static int is_client_alive(struct ion_client *client)
{
struct rb_node *node;
struct ion_client *tmp;
struct ion_device *dev;
node = ion_root_client->rb_node;
dev = container_of(ion_root_client, struct ion_device, clients);
down_read(&dev->lock);
while (node) {
tmp = rb_entry(node, struct ion_client, node);
if (client < tmp) {
node = node->rb_left;
} else if (client > tmp) {
node = node->rb_right;
} else {
up_read(&dev->lock);
return 1;
}
}
up_read(&dev->lock);
return 0;
}
static int ion_debug_client_show(struct seq_file *s, void *unused)
{
struct ion_client *client = s->private;
@ -685,6 +713,14 @@ static int ion_debug_client_show(struct seq_file *s, void *unused)
const char *names[ION_NUM_HEAP_IDS] = {NULL};
int i;
mutex_lock(&debugfs_mutex);
if (!is_client_alive(client)) {
seq_printf(s, "ion_client 0x%p dead, can't dump its buffers\n",
client);
mutex_unlock(&debugfs_mutex);
return 0;
}
mutex_lock(&client->lock);
for (n = rb_first(&client->handles); n; n = rb_next(n)) {
struct ion_handle *handle = rb_entry(n, struct ion_handle,
@ -696,6 +732,7 @@ static int ion_debug_client_show(struct seq_file *s, void *unused)
sizes[id] += handle->buffer->size;
}
mutex_unlock(&client->lock);
mutex_unlock(&debugfs_mutex);
seq_printf(s, "%16.16s: %16.16s\n", "heap_name", "size_in_bytes");
for (i = 0; i < ION_NUM_HEAP_IDS; i++) {
@ -832,6 +869,7 @@ void ion_client_destroy(struct ion_client *client)
struct rb_node *n;
pr_debug("%s: %d\n", __func__, __LINE__);
mutex_lock(&debugfs_mutex);
while ((n = rb_first(&client->handles))) {
struct ion_handle *handle = rb_entry(n, struct ion_handle,
node);
@ -850,6 +888,7 @@ void ion_client_destroy(struct ion_client *client)
kfree(client->display_name);
kfree(client->name);
kfree(client);
mutex_unlock(&debugfs_mutex);
}
EXPORT_SYMBOL(ion_client_destroy);
@ -1415,6 +1454,7 @@ static int ion_debug_heap_show(struct seq_file *s, void *unused)
seq_printf(s, "%16s %16s %16s\n", "client", "pid", "size");
seq_puts(s, "----------------------------------------------------\n");
mutex_lock(&debugfs_mutex);
for (n = rb_first(&dev->clients); n; n = rb_next(n)) {
struct ion_client *client = rb_entry(n, struct ion_client,
node);
@ -1433,6 +1473,8 @@ static int ion_debug_heap_show(struct seq_file *s, void *unused)
client->pid, size);
}
}
mutex_unlock(&debugfs_mutex);
seq_puts(s, "----------------------------------------------------\n");
seq_puts(s, "orphaned allocations (info is from last known client):\n");
mutex_lock(&dev->buffer_lock);
@ -1617,6 +1659,8 @@ struct ion_device *ion_device_create(long (*custom_ioctl)
init_rwsem(&idev->lock);
plist_head_init(&idev->heaps);
idev->clients = RB_ROOT;
ion_root_client = &idev->clients;
mutex_init(&debugfs_mutex);
return idev;
}
EXPORT_SYMBOL(ion_device_create);