6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tao Cui <redacted>
[ Upstream commit 482fc257de95ab181688e9d1dfcc6b6a58857b1e ]
kyber_timer_fn() sums the per-cpu latency histograms with
for_each_online_cpu(). A CPU that goes offline mid-interval leaves its
bucket un-flushed; the samples are lost from the current decision and
re-appear (stale) when the CPU is onlined again.
Fixes: 6e25cb01ea20 ("kyber: implement improved heuristics")
Signed-off-by: Tao Cui <redacted>
Reviewed-by: Yu Kuai <yukuai@fygo.io>
Link: https://patch.msgid.link/20260720093726.28965-5-cui.tao@linux.dev (local)
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/kyber-iosched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index b05357bced990..dc7d9a6079ec7 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -284,7 +284,7 @@ static void kyber_timer_fn(struct timer_list *t)
bool bad = false;
/* Sum all of the per-cpu latency histograms. */
- for_each_online_cpu(cpu) {
+ for_each_possible_cpu(cpu) {
struct kyber_cpu_latency *cpu_latency;
cpu_latency = per_cpu_ptr(kqd->cpu_latency, cpu);--
2.53.0