[PATCH] net: allow sleeping when modifying store_rps_map

From: Sasha Levin
Date: Thu Aug 13 2015 - 14:03:33 EST

Commit 10e4ea751 ("net: Fix race condition in store_rps_map") has moved the
manipulation of the rps_needed jump label under a spinlock. Since changing
the state of a jump label may sleep this is incorrect and causes warnings
during runtime.

Make rps_map_lock a mutex to allow sleeping under it.

Fixes: 10e4ea751 ("net: Fix race condition in store_rps_map")
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
net/core/net-sysfs.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 39ec694..b279077 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -689,7 +689,7 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue,
struct rps_map *old_map, *map;
cpumask_var_t mask;
int err, cpu, i;
- static DEFINE_SPINLOCK(rps_map_lock);
+ static DEFINE_MUTEX(rps_map_mutex);

if (!capable(CAP_NET_ADMIN))
return -EPERM;
@@ -722,9 +722,9 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue,
map = NULL;

- spin_lock(&rps_map_lock);
+ mutex_lock(&rps_map_mutex);
old_map = rcu_dereference_protected(queue->rps_map,
- lockdep_is_held(&rps_map_lock));
+ mutex_is_locked(&rps_map_mutex));
rcu_assign_pointer(queue->rps_map, map);

if (map)
@@ -732,7 +732,7 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue,
if (old_map)

- spin_unlock(&rps_map_lock);
+ mutex_unlock(&rps_map_mutex);

if (old_map)
kfree_rcu(old_map, rcu);

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