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authorNeil Brown <neilb@suse.de>2006-08-05 12:14:29 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-08-06 08:57:47 -0700
commit2f34931fdc78b4895553aaa33748939cc7697c99 (patch)
treec94736005fd9b9b67515c9e5518b3543d58ff488 /net/sunrpc/cache.c
parent9b7f750d446a717d4c8346fbb165b62661019b92 (diff)
[PATCH] knfsd: fix race related problem when adding items to and svcrpc auth cache
If we don't find the item we are lookng for, we allocate a new one, and then grab the lock again and search to see if it has been added while we did the alloc. If it had been added we need to 'cache_put' the newly created item that we are never going to use. But as it hasn't been initialised properly, putting it can cause an oops. So move the ->init call earlier to that it will always be fully initilised if we have to put it. Thanks to Philipp Matthias Hahn <pmhahn@svs.Informatik.Uni-Oldenburg.de> for reporting the problem. Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'net/sunrpc/cache.c')
-rw-r--r--net/sunrpc/cache.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 7026b0866b7..00cb388ece0 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -71,7 +71,12 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
new = detail->alloc();
if (!new)
return NULL;
+ /* must fully initialise 'new', else
+ * we might get lose if we need to
+ * cache_put it soon.
+ */
cache_init(new);
+ detail->init(new, key);
write_lock(&detail->hash_lock);
@@ -85,7 +90,6 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail,
return tmp;
}
}
- detail->init(new, key);
new->next = *head;
*head = new;
detail->entries++;