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net/sched: sch_htb: annotate data-races (III)

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htb_dump_class_stats() will soon run locklessly.

(no RTNL, not qdisc spinlock).

Add READ_ONCE()/WRITE_ONCE() annotations on these fields:

- cl->overlimits
- cl->drops
- cl->tokens
- cl->ctokens

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260514095935.3926276-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-05-14 09:59:35 +00:00 committed by Jakub Kicinski
parent 55562d4662
commit e249ae717b
1 changed files with 12 additions and 11 deletions
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23
net/sched/sch_htb.c
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@ -568,7 +568,7 @@ htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, s64 *diff)
return;
if (new_mode == HTB_CANT_SEND) {
cl->overlimits++;
WRITE_ONCE(cl->overlimits, cl->overlimits + 1);
WRITE_ONCE(q->overlimits, q->overlimits + 1);
}
@ -644,7 +644,7 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
to_free)) != NET_XMIT_SUCCESS) {
if (net_xmit_drop_count(ret)) {
qdisc_qstats_drop(sch);
cl->drops++;
WRITE_ONCE(cl->drops, cl->drops + 1);
}
return ret;
} else {
@ -666,7 +666,7 @@ static inline void htb_accnt_tokens(struct htb_class *cl, int bytes, s64 diff)
if (toks <= -cl->mbuffer)
toks = 1 - cl->mbuffer;
cl->tokens = toks;
WRITE_ONCE(cl->tokens, toks);
}
static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, s64 diff)
@ -679,7 +679,7 @@ static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, s64 diff)
if (toks <= -cl->mbuffer)
toks = 1 - cl->mbuffer;
cl->ctokens = toks;
WRITE_ONCE(cl->ctokens, toks);
}
/**
@ -712,7 +712,8 @@ static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
htb_accnt_tokens(cl, bytes, diff);
} else {
WRITE_ONCE(cl->xstats_borrows, cl->xstats_borrows + 1);
cl->tokens += diff; /* we moved t_c; update tokens */
/* we moved t_c; update tokens */
WRITE_ONCE(cl->tokens, cl->tokens + diff);
}
htb_accnt_ctokens(cl, bytes, diff);
cl->t_c = q->now;
@ -1325,17 +1326,17 @@ htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
.borrows = READ_ONCE(cl->xstats_borrows),
};
struct gnet_stats_queue qs = {
.drops = cl->drops,
.overlimits = cl->overlimits,
.drops = READ_ONCE(cl->drops),
.overlimits = READ_ONCE(cl->overlimits),
};
__u32 qlen = 0;
if (!cl->level && cl->leaf.q)
qdisc_qstats_qlen_backlog(cl->leaf.q, &qlen, &qs.backlog);
xstats.tokens = clamp_t(s64, PSCHED_NS2TICKS(cl->tokens),
xstats.tokens = clamp_t(s64, PSCHED_NS2TICKS(READ_ONCE(cl->tokens)),
INT_MIN, INT_MAX);
xstats.ctokens = clamp_t(s64, PSCHED_NS2TICKS(cl->ctokens),
xstats.ctokens = clamp_t(s64, PSCHED_NS2TICKS(READ_ONCE(cl->ctokens)),
INT_MIN, INT_MAX);
if (q->offload) {
@ -1517,8 +1518,8 @@ static void htb_parent_to_leaf(struct Qdisc *sch, struct htb_class *cl,
parent->level = 0;
memset(&parent->inner, 0, sizeof(parent->inner));
parent->leaf.q = new_q ? new_q : &noop_qdisc;
parent->tokens = parent->buffer;
parent->ctokens = parent->cbuffer;
WRITE_ONCE(parent->tokens, parent->buffer);
WRITE_ONCE(parent->ctokens, parent->cbuffer);
parent->t_c = ktime_get_ns();
parent->cmode = HTB_CAN_SEND;
if (q->offload)