From 82aeed2400786bd3f79d88cb8b8f42e6127e5923 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Tue, 25 Aug 2026 03:50:10 -0700 Subject: [PATCH] net: fix spurious TX timeout after dev_activate() While debugging another issue today, I found out that my TX queue is reported as stopped for 4294907392 ms (49.7 days), on a machine that had been up for four minutes. bnxt_en 0002:01:00.0 eth0: NETDEV WATCHDOG: CPU: 28: transmit queue 23 timed out 4294907392 ms 4294907392 is not an elapsed time. It is the value of jiffies at that moment: INITIAL_JIFFIES is 4294667296, which leaves jiffies 59 seconds short of wrapping. dev_activate() runs transition_one_qdisc() over every TX queue, which resets trans_start to 0, and then stamps only queue 0 through netif_trans_update(). Stamp jiffies instead. A queue stopped across dev_activate() now gets a full watchdog_timeo of grace, and is still reported if it is stopped that long. Fixes: 9b36627acecd ("net: remove dev->trans_start") Cc: stable@vger.kernel.org Signed-off-by: Breno Leitao Reviewed-by: Nicolai Buchwitz Reviewed-by: Jason Xing Link: https://patch.msgid.link/20260825-trans_start-v2-1-286b4d6d70cb@debian.org Signed-off-by: Paolo Abeni --- net/sched/sch_generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index ef2b4bf51564..4539dc2c6d38 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1278,7 +1278,7 @@ static void transition_one_qdisc(struct net_device *dev, rcu_assign_pointer(dev_queue->qdisc, new_qdisc); if (need_watchdog_p) { - WRITE_ONCE(dev_queue->trans_start, 0); + WRITE_ONCE(dev_queue->trans_start, jiffies); *need_watchdog_p = 1; } }