From: Pedro Tammela <pctammela@xxxxxxxxxxxx> [ Upstream commit 150e33e62c1fa4af5aaab02776b6c3812711d478 ] 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@xxxxxxxxxxxxxx/ v1 -> v2: Fix commit message Fixes: d4b36210c2e6 ("net: pkt_sched: PIE AQM scheme") Suggested-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Pedro Tammela <pctammela@xxxxxxxxxxxx> Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230711021634.561598-1-pctammela@xxxxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/net/pkt_sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h index ba781e0aaf566..e186b2bd8c860 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -136,7 +136,7 @@ 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) -- 2.39.2
