From 79ffdfc6522ae33d8a33e971070c08ee5f27439b Mon Sep 17 00:00:00 2001 From: Kirill Tkhai Date: Wed, 14 Mar 2018 22:17:20 +0300 Subject: [PATCH] net: Add rtnl_lock_killable() rtnl_lock() is widely used mutex in kernel. Some of kernel code does memory allocations under it. In case of memory deficit this may invoke OOM killer, but the problem is a killed task can't exit if it's waiting for the mutex. This may be a reason of deadlock and panic. This patch adds a new primitive, which responds on SIGKILL, and it allows to use it in the places, where we don't want to sleep forever. Signed-off-by: Kirill Tkhai Signed-off-by: David S. Miller --- include/linux/rtnetlink.h | 1 + net/core/rtnetlink.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 3573b4b..562a175 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -33,6 +33,7 @@ extern void rtnl_lock(void); extern void rtnl_unlock(void); extern int rtnl_trylock(void); extern int rtnl_is_locked(void); +extern int rtnl_lock_killable(void); extern wait_queue_head_t netdev_unregistering_wq; extern struct rw_semaphore net_sem; diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 67f375c..87079ea 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -75,6 +75,12 @@ void rtnl_lock(void) } EXPORT_SYMBOL(rtnl_lock); +int rtnl_lock_killable(void) +{ + return mutex_lock_killable(&rtnl_mutex); +} +EXPORT_SYMBOL(rtnl_lock_killable); + static struct sk_buff *defer_kfree_skb_list; void rtnl_kfree_skbs(struct sk_buff *head, struct sk_buff *tail) { -- 2.7.4