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| author | Tao Cui <cuitao@kylinos.cn> | 2026-08-04 13:41:20 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-08-04 07:23:04 -0600 |
| commit | 4d73bf0ca4fbe7f252154ce98d6693c6c198164c (patch) | |
| tree | 49038ba784f0f1c4379854e79c5dcc1bf9d5852b /block | |
| parent | 3bf9a21e7bccfd8c35b440efd114c61cc9838a41 (diff) | |
| download | linux-stable-4d73bf0ca4fbe7f252154ce98d6693c6c198164c.tar.gz linux-stable-4d73bf0ca4fbe7f252154ce98d6693c6c198164c.zip | |
block/blk-iocost: annotate ioc_pd_stat reads with data_race()
ioc_pd_stat() reads ioc->enabled, ioc->vtime_base_rate, and
iocg->last_stat without holding ioc->lock, which trips KCSAN since
ioc_adjust_base_vrate() and iocg_flush_stat_upward() write those
fields under ioc->lock.
Commit 35198e323001 fixed the same issue in ioc_qos_prfill() and
ioc_cost_model_prfill() by adding spin_lock_irq(&ioc->lock). However,
those functions read configuration parameters (qos/model) that need
synchronized reads. In contrast, ioc_pd_stat() only reads stat
values (vrate, usage) where stale reads are harmless, so data_race()
is more appropriate — it silences the KCSAN warning without adding
lock contention during high-frequency stat reads.
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://patch.msgid.link/20260804054120.161933-1-cui.tao@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-iocost.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/block/blk-iocost.c b/block/blk-iocost.c index b60625613e09..dd7749d59900 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -3093,23 +3093,23 @@ static void ioc_pd_stat(struct blkg_policy_data *pd, struct seq_file *s) struct ioc_gq *iocg = pd_to_iocg(pd); struct ioc *ioc = iocg->ioc; - if (!ioc->enabled) + if (!data_race(ioc->enabled)) return; if (iocg->level == 0) { unsigned vp10k = DIV64_U64_ROUND_CLOSEST( - ioc->vtime_base_rate * 10000, + data_race(ioc->vtime_base_rate) * 10000, VTIME_PER_USEC); seq_printf(s, " cost.vrate=%u.%02u", vp10k / 100, vp10k % 100); } - seq_printf(s, " cost.usage=%llu", iocg->last_stat.usage_us); + seq_printf(s, " cost.usage=%llu", data_race(iocg->last_stat.usage_us)); if (blkcg_debug_stats) seq_printf(s, " cost.wait=%llu cost.indebt=%llu cost.indelay=%llu", - iocg->last_stat.wait_us, - iocg->last_stat.indebt_us, - iocg->last_stat.indelay_us); + data_race(iocg->last_stat.wait_us), + data_race(iocg->last_stat.indebt_us), + data_race(iocg->last_stat.indelay_us)); } static u64 ioc_weight_prfill(struct seq_file *sf, struct blkg_policy_data *pd, |