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authorsjur.brandeland@stericsson.com <sjur.brandeland@stericsson.com>2012-02-02 01:21:02 +0000
committerDavid S. Miller <davem@davemloft.net>2012-02-02 14:35:12 -0500
commitb01377a4200d0dfc7b04a8daabb4739727353703 (patch)
tree2c1eef3ae76495872c2b55459c318e9a905c479f /net/caif
parentc31c151b1c4a29da4dc92212aa8648fb4f8557b9 (diff)
downloadlinux-b01377a4200d0dfc7b04a8daabb4739727353703.tar.gz
caif: Bugfix list_del_rcu race in cfmuxl_ctrlcmd.
Always use cfmuxl_remove_uplayer when removing a up-layer. cfmuxl_ctrlcmd() can be called independently and in parallel with cfmuxl_remove_uplayer(). The race between them could cause list_del_rcu to be called on a node which has been already taken out from the list. That lead to a (rare) crash on accessing poisoned node->prev inside list_del_rcu. This fix ensures that deletion are done holding the same lock. Reported-by: Dmitry Tarnyagin <dmitry.tarnyagin@stericsson.com> Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/caif')
-rw-r--r--net/caif/cfmuxl.c12
1 files changed, 3 insertions, 9 deletions
diff --git a/net/caif/cfmuxl.c b/net/caif/cfmuxl.c
index b36f24a4c8e..94b08612a4d 100644
--- a/net/caif/cfmuxl.c
+++ b/net/caif/cfmuxl.c
@@ -248,7 +248,6 @@ static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
{
struct cfmuxl *muxl = container_obj(layr);
struct cflayer *layer;
- int idx;
rcu_read_lock();
list_for_each_entry_rcu(layer, &muxl->srvl_list, node) {
@@ -257,14 +256,9 @@ static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
if ((ctrl == _CAIF_CTRLCMD_PHYIF_DOWN_IND ||
ctrl == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND) &&
- layer->id != 0) {
-
- idx = layer->id % UP_CACHE_SIZE;
- spin_lock_bh(&muxl->receive_lock);
- RCU_INIT_POINTER(muxl->up_cache[idx], NULL);
- list_del_rcu(&layer->node);
- spin_unlock_bh(&muxl->receive_lock);
- }
+ layer->id != 0)
+ cfmuxl_remove_uplayer(layr, layer->id);
+
/* NOTE: ctrlcmd is not allowed to block */
layer->ctrlcmd(layer, ctrl, phyid);
}