| Message ID | 20230711021634.561598-1-pctammela@mojatatu.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 150e33e62c1fa4af5aaab02776b6c3812711d478 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2,net] net/sched: make psched_mtu() RTNL-less safe | expand |
On Mon, Jul 10, 2023 at 11:16:34PM -0300, Pedro Tammela wrote: > Eric Dumazet says[1]: > ------- > Speaking of psched_mtu(), I see that net/sched/sch_pie.c is using it > without holding RTNL, so dev->mtu can be changed underneath. > KCSAN could issue a warning. > ------- > > Annotate dev->mtu with READ_ONCE() so KCSAN don't issue a warning. > > [1] https://lore.kernel.org/all/CANn89iJoJO5VtaJ-2=_d2aOQhb0Xw8iBT_Cxqp2HyuS-zj6azw@mail.gmail.com/ > > v1 -> v2: Fix commit message > > Fixes: d4b36210c2e6 ("net: pkt_sched: PIE AQM scheme") > Suggested-by: Eric Dumazet <edumazet@google.com> > Signed-off-by: Pedro Tammela <pctammela@mojatatu.com> Reviewed-by: Simon Horman <simon.horman@corigine.com>
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Mon, 10 Jul 2023 23:16:34 -0300 you wrote: > Eric Dumazet says[1]: > ------- > Speaking of psched_mtu(), I see that net/sched/sch_pie.c is using it > without holding RTNL, so dev->mtu can be changed underneath. > KCSAN could issue a warning. > ------- > > [...] Here is the summary with links: - [v2,net] net/sched: make psched_mtu() RTNL-less safe https://git.kernel.org/netdev/net/c/150e33e62c1f You are awesome, thank you!
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h index e98aac9d5ad5..15960564e0c3 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -134,7 +134,7 @@ extern const struct nla_policy rtm_tca_policy[TCA_MAX + 1]; */ static inline unsigned int psched_mtu(const struct net_device *dev) { - return dev->mtu + dev->hard_header_len; + return READ_ONCE(dev->mtu) + dev->hard_header_len; } static inline struct net *qdisc_net(struct Qdisc *q)
Eric Dumazet says[1]: ------- Speaking of psched_mtu(), I see that net/sched/sch_pie.c is using it without holding RTNL, so dev->mtu can be changed underneath. KCSAN could issue a warning. ------- Annotate dev->mtu with READ_ONCE() so KCSAN don't issue a warning. [1] https://lore.kernel.org/all/CANn89iJoJO5VtaJ-2=_d2aOQhb0Xw8iBT_Cxqp2HyuS-zj6azw@mail.gmail.com/ v1 -> v2: Fix commit message Fixes: d4b36210c2e6 ("net: pkt_sched: PIE AQM scheme") Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Pedro Tammela <pctammela@mojatatu.com> --- include/net/pkt_sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)