From 95278ddaa15cfa23e4a06ee9ed7b6ee0197c500b Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Tue, 2 Oct 2018 12:50:19 -0700 Subject: net_sched: convert idrinfo->lock from spinlock to a mutex In commit ec3ed293e766 ("net_sched: change tcf_del_walker() to take idrinfo->lock") we move fl_hw_destroy_tmplt() to a workqueue to avoid blocking with the spinlock held. Unfortunately, this causes a lot of troubles here: 1. tcf_chain_destroy() could be called right after we queue the work but before the work runs. This is a use-after-free. 2. The chain refcnt is already 0, we can't even just hold it again. We can check refcnt==1 but it is ugly. 3. The chain with refcnt 0 is still visible in its block, which means it could be still found and used! 4. The block has a refcnt too, we can't hold it without introducing a proper API either. We can make it working but the end result is ugly. Instead of wasting time on reviewing it, let's just convert the troubling spinlock to a mutex, which allows us to use non-atomic allocations too. Fixes: ec3ed293e766 ("net_sched: change tcf_del_walker() to take idrinfo->lock") Reported-by: Ido Schimmel Cc: Jamal Hadi Salim Cc: Vlad Buslov Cc: Jiri Pirko Signed-off-by: Cong Wang Tested-by: Ido Schimmel Signed-off-by: David S. Miller --- include/net/act_api.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/net/act_api.h') diff --git a/include/net/act_api.h b/include/net/act_api.h index 1ddff3360592..05c7df41d737 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -13,7 +13,7 @@ #include struct tcf_idrinfo { - spinlock_t lock; + struct mutex lock; struct idr action_idr; }; @@ -117,7 +117,7 @@ int tc_action_net_init(struct tc_action_net *tn, if (!tn->idrinfo) return -ENOMEM; tn->ops = ops; - spin_lock_init(&tn->idrinfo->lock); + mutex_init(&tn->idrinfo->lock); idr_init(&tn->idrinfo->action_idr); return err; } -- cgit v1.2.3-59-g8ed1b