diff options
| author |   Andrei Vagin <avagin@gmail.com> | 2018-08-08 20:07:35 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-08-09 14:25:06 -0700 |
| commit | 4d99f6602cb552fb58db0c3b1d935bb6fa017f24 (patch) | |
| tree | 01ef2703ee691058407b15164a05c7dea2f7c461 /net/core/net-sysfs.c | |
| parent | net: phy: sftp: print debug message with text, not numbers (diff) | |
| download | linux-dev-4d99f6602cb552fb58db0c3b1d935bb6fa017f24.tar.xz linux-dev-4d99f6602cb552fb58db0c3b1d935bb6fa017f24.zip | |
net: allow to call netif_reset_xps_queues() under cpus_read_lock
The definition of static_key_slow_inc() has cpus_read_lock in place. In the
virtio_net driver, XPS queues are initialized after setting the queue:cpu
affinity in virtnet_set_affinity() which is already protected within
cpus_read_lock. Lockdep prints a warning when we are trying to acquire
cpus_read_lock when it is already held.
This patch adds an ability to call __netif_set_xps_queue under
cpus_read_lock().
Acked-by: Jason Wang <jasowang@redhat.com>
============================================
WARNING: possible recursive locking detected
4.18.0-rc3-next-20180703+ #1 Not tainted
--------------------------------------------
swapper/0/1 is trying to acquire lock:
00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: static_key_slow_inc+0xe/0x20
but task is already holding lock:
00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: init_vqs+0x513/0x5a0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(cpu_hotplug_lock.rw_sem);
lock(cpu_hotplug_lock.rw_sem);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by swapper/0/1:
#0: 00000000244bc7da (&dev->mutex){....}, at: __driver_attach+0x5a/0x110
#1: 00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: init_vqs+0x513/0x5a0
#2: 000000005cd8463f (xps_map_mutex){+.+.}, at: __netif_set_xps_queue+0x8d/0xc60
v2: move cpus_read_lock() out of __netif_set_xps_queue()
Cc: "Nambiar, Amritha" <amritha.nambiar@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Fixes: 8af2c06ff4b1 ("net-sysfs: Add interface for Rx queue(s) map per Tx queue")
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/net-sysfs.c')
| -rw-r--r-- | net/core/net-sysfs.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 0a95bcf64cdc..bd67c4d0fcfd 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -26,6 +26,7 @@ #include <linux/pm_runtime.h> #include <linux/of.h> #include <linux/of_net.h> +#include <linux/cpu.h> #include "net-sysfs.h" @@ -1400,7 +1401,10 @@ static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf, return err; } + cpus_read_lock(); err = __netif_set_xps_queue(dev, mask, index, true); + cpus_read_unlock(); + kfree(mask); return err ? : len; } |