[PATCH] net: stmmac: ethtool: Fixed calltrace caused by unbalanced disable_irq_wake calls

[Qiang Ma]

We found the following dmesg calltrace when testing the GMAC NIC notebook:

[9.448656] ------------[ cut here ]------------
[9.448658] Unbalanced IRQ 43 wake disable
[9.448673] WARNING: CPU: 3 PID: 1083 at kernel/irq/manage.c:688 irq_set_irq_wake+0xe0/0x128
[9.448717] CPU: 3 PID: 1083 Comm: ethtool Tainted: G           O      4.19 #1
[9.448773]         ...
[9.448774] Call Trace:
[9.448781] [<9000000000209b5c>] show_stack+0x34/0x140
[9.448788] [<9000000000d52700>] dump_stack+0x98/0xd0
[9.448794] [<9000000000228610>] __warn+0xa8/0x120
[9.448797] [<9000000000d2fb60>] report_bug+0x98/0x130
[9.448800] [<900000000020a418>] do_bp+0x248/0x2f0
[9.448805] [<90000000002035f4>] handle_bp_int+0x4c/0x78
[9.448808] [<900000000029ea40>] irq_set_irq_wake+0xe0/0x128
[9.448813] [<9000000000a96a7c>] stmmac_set_wol+0x134/0x150
[9.448819] [<9000000000be6ed0>] dev_ethtool+0x1368/0x2440
[9.448824] [<9000000000c08350>] dev_ioctl+0x1f8/0x3e0
[9.448827] [<9000000000bb2a34>] sock_ioctl+0x2a4/0x450
[9.448832] [<900000000046f044>] do_vfs_ioctl+0xa4/0x738
[9.448834] [<900000000046f778>] ksys_ioctl+0xa0/0xe8
[9.448837] [<900000000046f7d8>] sys_ioctl+0x18/0x28
[9.448840] [<9000000000211ab4>] syscall_common+0x20/0x34
[9.448842] ---[ end trace 40c18d9aec863c3e ]---

Multiple disable_irq_wake() calls will keep decreasing the IRQ
wake_depth, When wake_depth is 0, calling disable_irq_wake() again,
will report the above calltrace.

Due to the need to appear in pairs, we cannot call disable_irq_wake()
without calling enable_irq_wake(). Fix this by making sure there are
no unbalanced disable_irq_wake() calls.

Signed-off-by: Qiang Ma <maqianga@xxxxxxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h         |  1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c | 10 ++++++++--
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c    |  1 +
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index cd7a9768de5f..b8c93b881a65 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -255,6 +255,7 @@ struct stmmac_priv {
 	u32 msg_enable;
 	int wolopts;
 	int wol_irq;
+	bool wol_irq_disabled;
 	int clk_csr;
 	struct timer_list eee_ctrl_timer;
 	int lpi_irq;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index f628411ae4ae..9a4d9492a781 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -825,10 +825,16 @@ static int stmmac_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
 	if (wol->wolopts) {
 		pr_info("stmmac: wakeup enable\n");
 		device_set_wakeup_enable(priv->device, 1);
-		enable_irq_wake(priv->wol_irq);
+		/* Avoid unbalanced enable_irq_wake calls */
+		if (priv->wol_irq_disabled)
+			enable_irq_wake(priv->wol_irq);
+		priv->wol_irq_disabled = false;
 	} else {
 		device_set_wakeup_enable(priv->device, 0);
-		disable_irq_wake(priv->wol_irq);
+		/* Avoid unbalanced disable_irq_wake calls */
+		if (!priv->wol_irq_disabled)
+			disable_irq_wake(priv->wol_irq);
+		priv->wol_irq_disabled = true;
 	}
 
 	mutex_lock(&priv->lock);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 37e64283f910..baa396621ed8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3565,6 +3565,7 @@ static int stmmac_request_irq_multi_msi(struct net_device *dev)
 	/* Request the Wake IRQ in case of another line
 	 * is used for WoL
 	 */
+	priv->wol_irq_disabled = true;
 	if (priv->wol_irq > 0 && priv->wol_irq != dev->irq) {
 		int_name = priv->int_name_wol;
 		sprintf(int_name, "%s:%s", dev->name, "wol");
-- 
2.20.1