From: Herbert Xu <herbert@gondor.apana.org.au>
When we are not the real parent of the dst (e.g., when we're xfrm_dst and
the child is an rtentry), it may already be on the GC list.
In fact the current code is buggy to, we need to check dst->flags before
the dec as dst may no longer be valid afterwards.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/net/core/dst.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff -puN net/core/dst.c~fix-dst_destroy-race net/core/dst.c
--- 25/net/core/dst.c~fix-dst_destroy-race 2005-04-06 01:39:29.000000000 -0700
+++ 25-akpm/net/core/dst.c 2005-04-06 01:39:29.000000000 -0700
@@ -198,13 +198,15 @@ again:
dst = child;
if (dst) {
+ int nohash = dst->flags & DST_NOHASH;
+
if (atomic_dec_and_test(&dst->__refcnt)) {
/* We were real parent of this dst, so kill child. */
- if (dst->flags&DST_NOHASH)
+ if (nohash)
goto again;
} else {
/* Child is still referenced, return it for freeing. */
- if (dst->flags&DST_NOHASH)
+ if (nohash)
return dst;
/* Child is still in his hash table */
}
_