From: Pedro Tammela pctammela@mojatatu.com
[ 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-zj6...
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 Link: https://lore.kernel.org/r/20230711021634.561598-1-pctammela@mojatatu.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 9cd2d4e84913f..d0d9dd2483dd3 100644 --- a/include/net/pkt_sched.h +++ b/include/net/pkt_sched.h @@ -141,7 +141,7 @@ 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)