| Message ID | 20240430180015.3111398-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | a17ef9e6c2c1cf0fc6cd6ca6a9ce525c67d1da7f |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] net_sched: sch_sfq: annotate data-races around q->perturb_period | expand |
On Tue, Apr 30, 2024 at 06:00:15PM +0000, Eric Dumazet wrote: > sfq_perturbation() reads q->perturb_period locklessly. > Add annotations to fix potential issues. > > Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Simon Horman <horms@kernel.org>
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Tue, 30 Apr 2024 18:00:15 +0000 you wrote: > sfq_perturbation() reads q->perturb_period locklessly. > Add annotations to fix potential issues. > > Signed-off-by: Eric Dumazet <edumazet@google.com> > --- > net/sched/sch_sfq.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) Here is the summary with links: - [net-next] net_sched: sch_sfq: annotate data-races around q->perturb_period https://git.kernel.org/netdev/net-next/c/a17ef9e6c2c1 You are awesome, thank you!
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c index e66f4afb920d28b2fcca1e15634b61ca41ee1bcc..3b9245a3c767a6feed5e06f90459ae896b217c23 100644 --- a/net/sched/sch_sfq.c +++ b/net/sched/sch_sfq.c @@ -608,6 +608,7 @@ static void sfq_perturbation(struct timer_list *t) struct Qdisc *sch = q->sch; spinlock_t *root_lock; siphash_key_t nkey; + int period; get_random_bytes(&nkey, sizeof(nkey)); rcu_read_lock(); @@ -618,8 +619,12 @@ static void sfq_perturbation(struct timer_list *t) sfq_rehash(sch); spin_unlock(root_lock); - if (q->perturb_period) - mod_timer(&q->perturb_timer, jiffies + q->perturb_period); + /* q->perturb_period can change under us from + * sfq_change() and sfq_destroy(). + */ + period = READ_ONCE(q->perturb_period); + if (period) + mod_timer(&q->perturb_timer, jiffies + period); rcu_read_unlock(); } @@ -662,7 +667,7 @@ static int sfq_change(struct Qdisc *sch, struct nlattr *opt) q->quantum = ctl->quantum; q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum); } - q->perturb_period = ctl->perturb_period * HZ; + WRITE_ONCE(q->perturb_period, ctl->perturb_period * HZ); if (ctl->flows) q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS); if (ctl->divisor) { @@ -724,7 +729,7 @@ static void sfq_destroy(struct Qdisc *sch) struct sfq_sched_data *q = qdisc_priv(sch); tcf_block_put(q->block); - q->perturb_period = 0; + WRITE_ONCE(q->perturb_period, 0); del_timer_sync(&q->perturb_timer); sfq_free(q->ht); sfq_free(q->slots);
sfq_perturbation() reads q->perturb_period locklessly. Add annotations to fix potential issues. Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/sched/sch_sfq.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)