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authorEric Dumazet <edumazet@google.com>2015-11-10 02:51:23 +0100
committerDavid S. Miller <davem@davemloft.net>2015-11-10 03:55:48 +0100
commitd69bbf88c8d0b367cf3e3a052f6daadf630ee566 (patch)
tree32b81467f642ab7a2b6d0b20b2a935eb85bae712 /net/core
parentnet: mvneta: Fix memory use after free. (diff)
downloadlinux-d69bbf88c8d0b367cf3e3a052f6daadf630ee566.tar.xz
linux-d69bbf88c8d0b367cf3e3a052f6daadf630ee566.zip
net: fix a race in dst_release()
Only cpu seeing dst refcount going to 0 can safely dereference dst->flags. Otherwise an other cpu might already have freed the dst. Fixes: 27b75c95f10d ("net: avoid RCU for NOCACHE dst") Reported-by: Greg Thelen <gthelen@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/dst.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/dst.c b/net/core/dst.c
index 2a1818065e12..e6dc77252fe9 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -306,7 +306,7 @@ void dst_release(struct dst_entry *dst)
if (unlikely(newrefcnt < 0))
net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
__func__, dst, newrefcnt);
- if (unlikely(dst->flags & DST_NOCACHE) && !newrefcnt)
+ if (!newrefcnt && unlikely(dst->flags & DST_NOCACHE))
call_rcu(&dst->rcu_head, dst_destroy_rcu);
}
}