From: Michael Chan <michael.chan@broadcom.com>
Date: Thu, 3 Sep 2020 14:28:54 -0400
Subject: tg3: Fix soft lockup when tg3_reset_task() fails.
Git-commit: 556699341efa98243e08e34401b3f601da91f5a3
Patch-mainline: 5.9-rc4
References: networking-stable-20_09_11

If tg3_reset_task() fails, the device state is left in an inconsistent
state with IFF_RUNNING still set but NAPI state not enabled.  A
subsequent operation, such as ifdown or AER error can cause it to
soft lock up when it tries to disable NAPI state.

Fix it by bringing down the device to !IFF_RUNNING state when
tg3_reset_task() fails.  tg3_reset_task() running from workqueue
will now call tg3_close() when the reset fails.  We need to
modify tg3_reset_task_cancel() slightly to avoid tg3_close()
calling cancel_work_sync() to cancel tg3_reset_task().  Otherwise
cancel_work_sync() will wait forever for tg3_reset_task() to
finish.

Reported-by: David Christensen <drc@linux.vnet.ibm.com>
Reported-by: Baptiste Covolato <baptiste@arista.com>
Fixes: db2199737990 ("tg3: Schedule at most one tg3_reset_task run")
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/net/ethernet/broadcom/tg3.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -7212,8 +7212,8 @@ static inline void tg3_reset_task_schedu
 
 static inline void tg3_reset_task_cancel(struct tg3 *tp)
 {
-	cancel_work_sync(&tp->reset_task);
-	tg3_flag_clear(tp, RESET_TASK_PENDING);
+	if (test_and_clear_bit(TG3_FLAG_RESET_TASK_PENDING, tp->tg3_flags))
+		cancel_work_sync(&tp->reset_task);
 	tg3_flag_clear(tp, TX_RECOVERY_PENDING);
 }
 
@@ -11207,18 +11207,27 @@ static void tg3_reset_task(struct work_s
 
 	tg3_halt(tp, RESET_KIND_SHUTDOWN, 0);
 	err = tg3_init_hw(tp, true);
-	if (err)
+	if (err) {
+		tg3_full_unlock(tp);
+		tp->irq_sync = 0;
+		tg3_napi_enable(tp);
+		/* Clear this flag so that tg3_reset_task_cancel() will not
+		 * call cancel_work_sync() and wait forever.
+		 */
+		tg3_flag_clear(tp, RESET_TASK_PENDING);
+		dev_close(tp->dev);
 		goto out;
+	}
 
 	tg3_netif_start(tp);
 
-out:
 	tg3_full_unlock(tp);
 
 	if (!err)
 		tg3_phy_start(tp);
 
 	tg3_flag_clear(tp, RESET_TASK_PENDING);
+out:
 	rtnl_unlock();
 }