Hi Rob & Dmitry,
On 03/24/2017 06:58 AM, Dmitry Torokhov wrote:
On Thu, Mar 23, 2017 at 3:07 PM, Rob Herring <robh@xxxxxxxxxx> wrote:
On Thu, Mar 23, 2017 at 3:12 AM, Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx> wrote:
Currently we only free the allocated resource struct when error.
This would cause memory leak after pci_free_resource_list.
Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
---
Changes in v2:
Don't change the resource_list_create_entry's behavior.
drivers/of/of_pci.c | 57 +++++++++++++++++++++++------------------------------
1 file changed, 25 insertions(+), 32 deletions(-)
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 0ee42c3..a0ec246 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -190,8 +190,7 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
struct list_head *resources, resource_size_t *io_base)
{
struct resource_entry *window;
- struct resource *res;
- struct resource *bus_range;
+ struct resource res;
struct of_pci_range range;
struct of_pci_range_parser parser;
char range_type[4];
@@ -200,24 +199,24 @@ int of_pci_get_host_bridge_resources(struct device_node *dev,
if (io_base)
*io_base = (resource_size_t)OF_BAD_ADDR;
- bus_range = kzalloc(sizeof(*bus_range), GFP_KERNEL);
- if (!bus_range)
- return -ENOMEM;
-
pr_info("host bridge %s ranges:\n", dev->full_name);
- err = of_pci_parse_bus_range(dev, bus_range);
+ err = of_pci_parse_bus_range(dev, &res);
if (err) {
- bus_range->start = busno;
- bus_range->end = bus_max;
- bus_range->flags = IORESOURCE_BUS;
- pr_info(" No bus range found for %s, using %pR\n",
- dev->full_name, bus_range);
+ res.start = busno;
+ res.end = bus_max;
+ res.flags = IORESOURCE_BUS;
+ pr_info(" No bus range found for %s\n", dev->full_name);
} else {
- if (bus_range->end > bus_range->start + bus_max)
- bus_range->end = bus_range->start + bus_max;
+ if (res.end > res.start + bus_max)
+ res.end = res.start + bus_max;
+ }
+ window = pci_add_resource(resources, NULL);
+ if (!window) {
+ err = -ENOMEM;
+ goto parse_failed;
}
- pci_add_resource(resources, bus_range);
+ *window->res = res;
Well, now this seems racy. You add a blank resource to the list first
and then fill it in.
Huh? There is absolutely no guarantees for concurrent access here.
pcI_add_resource_offset() first adds a resource and then modifies
offset. Here we add an empty resource and then fill it in.
currently, we are using of_pci_get_host_bridge_resources in this pattern:
create resource list:
LIST_HEAD(res);
...
add resources into the list:
err = of_pci_get_host_bridge_resources(dev->of_node, 0, 0xff,
&res, &io_base);
...
walk over the list:
/* Get the I/O and memory ranges from DT */
resource_list_for_each_entry(win, &res) {
so only of_pci_get_host_bridge_resources is accessing this list at that
time.
and an empty resource is harmless i think(with zero size and flags) ;)
maybe i should add some comments in the patch
Thanks.
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