linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Yunsheng Lin <linyunsheng@huawei.com>
To: <gregkh@linuxfoundation.org>, <stable@vger.kernel.org>
Cc: <vpai@akamai.com>, <Joakim.Tjernlund@infinera.com>,
	<xiyou.wangcong@gmail.com>, <johunt@akamai.com>,
	<jhs@mojatatu.com>, <jiri@resnulli.us>, <davem@davemloft.net>,
	<kuba@kernel.org>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <linuxarm@huawei.com>,
	<john.fastabend@gmail.com>, <eric.dumazet@gmail.com>,
	<dsahern@gmail.com>
Subject: [PATCH stable] net: sch_generic: fix the missing new qdisc assignment bug
Date: Tue, 3 Nov 2020 11:25:38 +0800	[thread overview]
Message-ID: <1604373938-211588-1-git-send-email-linyunsheng@huawei.com> (raw)

commit 2fb541c862c9 ("net: sch_generic: aviod concurrent reset and enqueue op for lockless qdisc")

When the above upstream commit is backported to stable kernel,
one assignment is missing, which causes two problems reported
by Joakim and Vishwanath, see [1] and [2].

So add the assignment back to fix it.

1. https://www.spinics.net/lists/netdev/msg693916.html
2. https://www.spinics.net/lists/netdev/msg695131.html

Fixes: 749cc0b0c7f3 ("net: sch_generic: aviod concurrent reset and enqueue op for lockless qdisc")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 net/sched/sch_generic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 0e275e1..6e6147a 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -1127,10 +1127,13 @@ static void dev_deactivate_queue(struct net_device *dev,
 				 void *_qdisc_default)
 {
 	struct Qdisc *qdisc = rtnl_dereference(dev_queue->qdisc);
+	struct Qdisc *qdisc_default = _qdisc_default;
 
 	if (qdisc) {
 		if (!(qdisc->flags & TCQ_F_BUILTIN))
 			set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
+
+		rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
 	}
 }
 
-- 
2.7.4


             reply	other threads:[~2020-11-03  3:29 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-03  3:25 Yunsheng Lin [this message]
2020-11-03 15:46 ` [PATCH stable] net: sch_generic: fix the missing new qdisc assignment bug Vishwanath Pai
2020-11-03 19:06 ` Jakub Kicinski
2020-11-09 12:46 ` Greg KH
2020-11-10  0:58   ` Yunsheng Lin
2020-11-17 12:09     ` Greg KH
2020-11-13  3:51 ` Brian Norris

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1604373938-211588-1-git-send-email-linyunsheng@huawei.com \
    --to=linyunsheng@huawei.com \
    --cc=Joakim.Tjernlund@infinera.com \
    --cc=davem@davemloft.net \
    --cc=dsahern@gmail.com \
    --cc=eric.dumazet@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jhs@mojatatu.com \
    --cc=jiri@resnulli.us \
    --cc=john.fastabend@gmail.com \
    --cc=johunt@akamai.com \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxarm@huawei.com \
    --cc=netdev@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --cc=vpai@akamai.com \
    --cc=xiyou.wangcong@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).