Commit 91dfae03 authored by Dmitry Antipov's avatar Dmitry Antipov Committed by Wen Zhiwei
Browse files

net: sched: consistently use rcu_replace_pointer() in taprio_change() 

stable inclusion
from stable-v6.6.55
commit 37a6fc0d8fca8fd2e34835a6faabc7955fcd1419
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IB0MX4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=37a6fc0d8fca8fd2e34835a6faabc7955fcd1419

--------------------------------

[ Upstream commit d5c4546062fd6f5dbce575c7ea52ad66d1968678 ]

According to Vinicius (and carefully looking through the whole
https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa


once again), txtime branch of 'taprio_change()' is not going to
race against 'advance_sched()'. But using 'rcu_replace_pointer()'
in the former may be a good idea as well.

Suggested-by: default avatarVinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: default avatarDmitry Antipov <dmantipov@yandex.ru>
Acked-by: default avatarVinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent 12d4e00d

net/sched/sch_taprio.c

+3 −1
Original line number Diff line number Diff line
@@ -1975,7 +1975,9 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, 
			goto unlock;

		}



		rcu_assign_pointer(q->admin_sched, new_admin);

		/* Not going to race against advance_sched(), but still */

		admin = rcu_replace_pointer(q->admin_sched, new_admin,

					    lockdep_rtnl_is_held());

		if (admin)

			call_rcu(&admin->rcu, taprio_free_sched_cb);

	} else {