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authorJakub Kicinski <kuba@kernel.org>2023-01-12 20:41:37 -0800
committerJakub Kicinski <kuba@kernel.org>2023-01-18 20:28:25 -0800
commit339346d49ae0859fe19b860998867861d37f1a76 (patch)
tree008f4d986d20f21879d66819508b62bf4ed3d862 /net
parentedb5b63e5673add742a860814a4f43ff213178ea (diff)
net: sched: gred: prevent races when adding offloads to stats
Naresh reports seeing a warning that gred is calling u64_stats_update_begin() with preemption enabled. Arnd points out it's coming from _bstats_update(). We should be holding the qdisc lock when writing to stats, they are also updated from the datapath. Reported-by: Linux Kernel Functional Testing <lkft@linaro.org> Link: https://lore.kernel.org/all/CA+G9fYsTr9_r893+62u6UGD3dVaCE-kN9C-Apmb2m=hxjc1Cqg@mail.gmail.com/ Fixes: e49efd5288bd ("net: sched: gred: support reporting stats from offloads") Link: https://lore.kernel.org/r/20230113044137.1383067-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/sched/sch_gred.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index a661b062cca8..872d127c9db4 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -377,6 +377,7 @@ static int gred_offload_dump_stats(struct Qdisc *sch)
/* Even if driver returns failure adjust the stats - in case offload
* ended but driver still wants to adjust the values.
*/
+ sch_tree_lock(sch);
for (i = 0; i < MAX_DPs; i++) {
if (!table->tab[i])
continue;
@@ -393,6 +394,7 @@ static int gred_offload_dump_stats(struct Qdisc *sch)
sch->qstats.overlimits += hw_stats->stats.qstats[i].overlimits;
}
_bstats_update(&sch->bstats, bytes, packets);
+ sch_tree_unlock(sch);
kfree(hw_stats);
return ret;