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authorNikita Yushchenko <nikita.yoush@cogentembedded.com>2016-11-28 09:48:48 +0300
committerDavid S. Miller <davem@davemloft.net>2016-11-28 16:15:45 -0500
commit7a99cd6e213685b78118382e6a8fed506c82ccb2 (patch)
treef08b04e49d5002be5dcee747fe5b91b0eb112ef7 /net/dsa
parent79dc7e3f1cd323be4c81aa1a94faa1b3ed987fb2 (diff)
downloadlinux-7a99cd6e213685b78118382e6a8fed506c82ccb2.tar.bz2
net: dsa: fix unbalanced dsa_switch_tree reference counting
_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(). Fixes: 83c0afaec7b7 ("net: dsa: Add new binding implementation") Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dsa')
-rw-r--r--net/dsa/dsa2.c4
1 files changed, 3 insertions, 1 deletions
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;
}