_dsa_register_switch() gets a dsa_switch_tree object either via
dsa_get_dst() or via dsa_add_dst(). Former path does not increase kref
in returned object (resulting into caller not owning a reference),
while later path does create a new object (resulting into caller owning
a reference).
The rest of _dsa_register_switch() assumes that it owns a reference, and
calls dsa_put_dst().
This causes a memory breakage if first switch in the tree initialized
successfully, but second failed to initialize. In particular, freed
dsa_swith_tree object is left referenced by switch that was initialized,
and later access to sysfs attributes of that switch cause OOPS.
To fix, need to add kref_get() call to dsa_get_dst().
Signed-off-by: Nikita Yushchenko <nikita.yo...@cogentembedded.com>
---
net/dsa/dsa2.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index f8a7d9aab437..5fff951a0a49 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -28,8 +28,10 @@ static struct dsa_switch_tree *dsa_get_dst(u32 tree)
struct dsa_switch_tree *dst;
list_for_each_entry(dst, &dsa_switch_trees, list)
- if (dst->tree == tree)
+ if (dst->tree == tree) {
+ kref_get(&dst->refcount);
return dst;
+ }
return NULL;
}
--
2.1.4
