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| author | NeilBrown <neilb@suse.com> | 2019-04-05 11:34:40 +1100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-16 09:17:13 +0200 |
| commit | b0b38ec243465c545874e7aec262fe5168aed049 (patch) | |
| tree | 0d58b2a6d0863db57faa730b15480317f281f381 /net | |
| parent | 596c78267376e4082b36be56743579369dcfd508 (diff) | |
| download | linux-stable-b0b38ec243465c545874e7aec262fe5168aed049.tar.gz linux-stable-b0b38ec243465c545874e7aec262fe5168aed049.tar.bz2 linux-stable-b0b38ec243465c545874e7aec262fe5168aed049.zip | |
sunrpc: don't mark uninitialised items as VALID.
commit d58431eacb226222430940134d97bfd72f292fcd upstream.
A recent commit added a call to cache_fresh_locked()
when an expired item was found.
The call sets the CACHE_VALID flag, so it is important
that the item actually is valid.
There are two ways it could be valid:
1/ If ->update has been called to fill in relevant content
2/ if CACHE_NEGATIVE is set, to say that content doesn't exist.
An expired item that is waiting for an update will be neither.
Setting CACHE_VALID will mean that a subsequent call to cache_put()
will be likely to dereference uninitialised pointers.
So we must make sure the item is valid, and we already have code to do
that in try_to_negate_entry(). This takes the hash lock and so cannot
be used directly, so take out the two lines that we need and use them.
Now cache_fresh_locked() is certain to be called only on
a valid item.
Cc: stable@kernel.org # 2.6.35
Fixes: 4ecd55ea0742 ("sunrpc: fix cache_head leak due to queued request")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sunrpc/cache.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index cdfa7f4c0a59..4a5598a42cd6 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -50,6 +50,7 @@ static void cache_init(struct cache_head *h) h->last_refresh = now; } +static inline int cache_is_valid(struct cache_head *h); static void cache_fresh_locked(struct cache_head *head, time_t expiry); static void cache_fresh_unlocked(struct cache_head *head, struct cache_detail *detail); @@ -98,6 +99,8 @@ struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, *hp = tmp->next; tmp->next = NULL; detail->entries --; + if (cache_is_valid(tmp) == -EAGAIN) + set_bit(CACHE_NEGATIVE, &tmp->flags); cache_fresh_locked(tmp, 0); freeme = tmp; break; |