| Message ID | 20240904115401.3425674-1-dmantipov@yandex.ru (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | d5c4546062fd6f5dbce575c7ea52ad66d1968678 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v5] net: sched: consistently use rcu_replace_pointer() in taprio_change() | expand |
Dmitry Antipov <dmantipov@yandex.ru> writes: > 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: Vinicius Costa Gomes <vinicius.gomes@intel.com> > Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> > --- > v5: cut from the series, add syzbot link an re-target to net-next > v4: adjust subject to target net tree > v3: unchanged since v2 > v2: added to the series > --- Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> Cheers,
Hello: This patch was applied to netdev/net-next.git (main) by David S. Miller <davem@davemloft.net>: On Wed, 4 Sep 2024 14:54:01 +0300 you wrote: > 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: Vinicius Costa Gomes <vinicius.gomes@intel.com> > Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> > > [...] Here is the summary with links: - [net-next,v5] net: sched: consistently use rcu_replace_pointer() in taprio_change() https://git.kernel.org/netdev/net-next/c/d5c4546062fd You are awesome, thank you!
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index cc2df9f8c14a..8498d0606b24 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1952,7 +1952,9 @@ 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 {
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: Vinicius Costa Gomes <vinicius.gomes@intel.com> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> --- v5: cut from the series, add syzbot link an re-target to net-next v4: adjust subject to target net tree v3: unchanged since v2 v2: added to the series --- net/sched/sch_taprio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)