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| author | sjur.brandeland@stericsson.com <sjur.brandeland@stericsson.com> | 2012-02-02 01:21:02 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-02-02 14:35:12 -0500 |
| commit | b01377a4200d0dfc7b04a8daabb4739727353703 (patch) | |
| tree | 2c1eef3ae76495872c2b55459c318e9a905c479f /net/caif/cfmuxl.c | |
| parent | c31c151b1c4a29da4dc92212aa8648fb4f8557b9 (diff) | |
| download | linux-b01377a4200d0dfc7b04a8daabb4739727353703.tar.gz linux-b01377a4200d0dfc7b04a8daabb4739727353703.tar.bz2 linux-b01377a4200d0dfc7b04a8daabb4739727353703.zip | |
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/cfmuxl.c')
| -rw-r--r-- | net/caif/cfmuxl.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/net/caif/cfmuxl.c b/net/caif/cfmuxl.c index b36f24a4c8e7..94b08612a4d8 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); } |