netdev - [PATCH] qede: fix crash in rmmod qede while automatic debug collection

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Date:   Thu, 29 Jul 2021 14:43:06 +0300
From:   Prabhakar Kushwaha <pkushwaha@...vell.com>
To:     <netdev@...r.kernel.org>, <davem@...emloft.net>, <kuba@...nel.org>
CC:     <smalin@...vell.com>, <aelior@...vell.com>,
        <pkushwaha@...vell.com>, <prabhakar.pkin@...il.com>,
        <malin1024@...il.com>, Alok Prasad <palok@...vell.com>
Subject: [PATCH] qede: fix crash in rmmod qede while automatic debug collection

A crash has been observed if rmmod is done while automatic debug
collection in progress. It is due to a race  condition between
both of them.

To fix stop the sp_task during unload to avoid running qede_sp_task
even if they are schedule during removal process.

Signed-off-by: Alok Prasad <palok@...vell.com>
Signed-off-by: Shai Malin <smalin@...vell.com>
Signed-off-by: Ariel Elior <aelior@...vell.com>
Signed-off-by: Prabhakar Kushwaha <pkushwaha@...vell.com>
---
 drivers/net/ethernet/qlogic/qede/qede.h      | 1 +
 drivers/net/ethernet/qlogic/qede/qede_main.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qede/qede.h b/drivers/net/ethernet/qlogic/qede/qede.h
index 2e62a2c4eb63..5630008f38b7 100644
--- a/drivers/net/ethernet/qlogic/qede/qede.h
+++ b/drivers/net/ethernet/qlogic/qede/qede.h
@@ -501,6 +501,7 @@ struct qede_fastpath {
 #define QEDE_SP_HW_ERR                  4
 #define QEDE_SP_ARFS_CONFIG             5
 #define QEDE_SP_AER			7
+#define QEDE_SP_DISABLE			8
 
 #ifdef CONFIG_RFS_ACCEL
 int qede_rx_flow_steer(struct net_device *dev, const struct sk_buff *skb,
diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c b/drivers/net/ethernet/qlogic/qede/qede_main.c
index 173878696143..6a4bc7652d2e 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_main.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
@@ -1009,6 +1009,13 @@ static void qede_sp_task(struct work_struct *work)
 	struct qede_dev *edev = container_of(work, struct qede_dev,
 					     sp_task.work);
 
+	/* Disable execution of this deferred work once
+	 * qede removal is in progress, this stop any future
+	 * scheduling of sp_task.
+	 */
+	if (test_bit(QEDE_SP_DISABLE, &edev->sp_flags))
+		return;
+
 	/* The locking scheme depends on the specific flag:
 	 * In case of QEDE_SP_RECOVERY, acquiring the RTNL lock is required to
 	 * ensure that ongoing flows are ended and new ones are not started.
@@ -1300,6 +1307,7 @@ static void __qede_remove(struct pci_dev *pdev, enum qede_remove_mode mode)
 	qede_rdma_dev_remove(edev, (mode == QEDE_REMOVE_RECOVERY));
 
 	if (mode != QEDE_REMOVE_RECOVERY) {
+		set_bit(QEDE_SP_DISABLE, &edev->sp_flags);
 		unregister_netdev(ndev);
 
 		cancel_delayed_work_sync(&edev->sp_task);
-- 
2.24.1