From: Sean Wang
Lockdep found an inconsistent lock state when mtk_get_stats64 is called
in user context while NAPI updates MAC statistics in softirq.
Use spin_trylock_bh/spin_unlock_bh fix following lockdep warning.
[ 81.321030] WARNING: inconsistent lock state
[ 81.325266] 4.12.0-rc1-00035-gd9dda65 #32 Not tainted
[ 81.330273]
[ 81.334505] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[ 81.340464] ksoftirqd/0/7 [HC0[0]:SC1[1]:HE1:SE0] takes:
[ 81.345731] (&syncp->seq#2){+.?...}, at: []
mtk_handle_status_irq.part.6+0x70/0x84
[ 81.354219] {SOFTIRQ-ON-W} state was registered at:
[ 81.359062] lock_acquire+0xfc/0x2b0
[ 81.362696] mtk_stats_update_mac+0x60/0x2c0
[ 81.367017] mtk_get_stats64+0x17c/0x18c
[ 81.370995] dev_get_stats+0x48/0xbc
[ 81.374628] rtnl_fill_stats+0x48/0x128
[ 81.378520] rtnl_fill_ifinfo+0x4ac/0xd1c
[ 81.382584] rtmsg_ifinfo_build_skb+0x7c/0xe0
[ 81.386991] rtmsg_ifinfo.part.5+0x24/0x54
[ 81.391139] rtmsg_ifinfo+0x24/0x28
[ 81.394685] __dev_notify_flags+0xa4/0xac
[ 81.398749] dev_change_flags+0x50/0x58
[ 81.402640] devinet_ioctl+0x768/0x85c
[ 81.406444] inet_ioctl+0x1a4/0x1d0
[ 81.409990] sock_ioctl+0x16c/0x33c
[ 81.413538] do_vfs_ioctl+0xb4/0xa34
[ 81.417169] SyS_ioctl+0x44/0x6c
[ 81.420458] ret_fast_syscall+0x0/0x1c
[ 81.424260] irq event stamp: 3354692
[ 81.427806] hardirqs last enabled at (3354692): []
net_rx_action+0xc0/0x504
[ 81.435660] hardirqs last disabled at (3354691): []
net_rx_action+0x8c/0x504
[ 81.443515] softirqs last enabled at (3354106): []
__do_softirq+0x4b4/0x614
[ 81.451370] softirqs last disabled at (3354109): []
run_ksoftirqd+0x44/0x80
[ 81.459134]
[ 81.459134] other info that might help us debug this:
[ 81.465608] Possible unsafe locking scenario:
[ 81.465608]
[ 81.471478]CPU0
[ 81.473900]
[ 81.476321] lock(&syncp->seq#2);
[ 81.479701]
[ 81.482294] lock(&syncp->seq#2);
[ 81.485847]
[ 81.485847] *** DEADLOCK ***
[ 81.485847]
[ 81.491720] 1 lock held by ksoftirqd/0/7:
[ 81.495693] #0: (&(&mac->hw_stats->stats_lock)->rlock){+.+...}, at:
[] mtk_handle_status_irq.part.6+0x48/0x84
[ 81.506579]
[ 81.506579] stack backtrace:
[ 81.510904] CPU: 0 PID: 7 Comm: ksoftirqd/0 Not tainted
4.12.0-rc1-00035-gd9dda65 #32
[ 81.518668] Hardware name: Mediatek Cortex-A7 (Device Tree)
[ 81.524208] [] (unwind_backtrace) from []
(show_stack+0x20/0x24)
[ 81.531899] [] (show_stack) from []
(dump_stack+0xb4/0xe0)
[ 81.539072] [] (dump_stack) from []
(print_usage_bug+0x234/0x2e0)
[ 81.546846] [] (print_usage_bug) from []
(mark_lock+0x63c/0x7bc)
[ 81.554532] [] (mark_lock) from []
(__lock_acquire+0x654/0x1bfc)
[ 81.562217] [] (__lock_acquire) from []
(lock_acquire+0xfc/0x2b0)
[ 81.569990] [] (lock_acquire) from []
(mtk_stats_update_mac+0x60/0x2c0)
[ 81.578283] [] (mtk_stats_update_mac) from []
(mtk_handle_status_irq.part.6+0x70/0x84)
[ 81.587865] [] (mtk_handle_status_irq.part.6) from []
(mtk_napi_tx+0x358/0x37c)
[ 81.596845] [] (mtk_napi_tx) from []
(net_rx_action+0x244/0x504)
[ 81.604533] [] (net_rx_action) from []
(__do_softirq+0x134/0x614)
[ 81.612306] [] (__do_softirq) from []
(run_ksoftirqd+0x44/0x80)
[ 81.619907] [] (run_ksoftirqd) from []
(smpboot_thread_fn+0x14c/0x25c)
[ 81.628110] [] (smpboot_thread_fn) from []
(kthread+0x150/0x180)
[ 81.635798] [] (kthread) from []
(ret_from_fork+0x14/0x24)
Signed-off-by: Sean Wang
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 16f9755..8a2acb8 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -470,9 +470,9 @@ static void mtk_get_stats64(struct net_device *dev,
unsigned int start;
if (netif_running(dev) && netif_device_present(dev)) {
- if (spin_trylock(&hw_stats->stats_lock)) {
+ if (spin_trylock_bh(&hw_stats->stats_lock)) {
mtk_stats_update_mac(mac);
- spin_unlock(&hw_stats->stats_lock);
+ spin_unlock_bh(&hw_stats->stats_lock);
}
}
@@ -2156,9 +2156,9 @@ static void mtk_get_ethtool_stats(struct net_device *dev,
return;
if (netif_running(dev) && netif_device_present(dev)) {
- if (spin_trylock(&hwstats->stats_lock)) {
+ if (spin_trylock_bh(&hwstats->stats_lock)) {
mtk_stats_update_mac(mac);
- spin_unlock(&hwstats->stats_lock);
+ spin_unlock_bh(&hwstats->stats_lock);
}
}
--
2.7.4
