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net/sched: fq_pie: re-factor fix for fq_pie endless loop

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the patch that fixed an endless loop in_fq_pie_init() was not considering
that 65535 is a valid class id. The correct bugfix for this infinite loop
is to change 'idx' to become an u32, like Colin proposed in the past [1].

Fix this as follows:
 - restore 65536 as maximum possible values of 'flows_cnt'
 - use u32 'idx' when iterating on 'q->flows'
 - fix the TDC selftest

This reverts commit bb2f930d6d.

[1] https://lore.kernel.org/netdev/20210407163808.499027-1-colin.king@canonical.com/

CC: Colin Ian King <colin.king@canonical.com>
CC: stable@vger.kernel.org
Fixes: bb2f930d6d ("net/sched: fix infinite loop in sch_fq_pie")
Fixes: ec97ecf1eb ("net: sched: add Flow Queue PIE packet scheduler")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Davide Caratti 2021-05-22 15:14:45 +02:00 committed by David S. Miller
parent 5eff1461a6
commit 3a62fed2fd
2 changed files with 9 additions and 9 deletions
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10
net/sched/sch_fq_pie.c
View File

@ -297,9 +297,9 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr *opt,
goto flow_error;
}
q->flows_cnt = nla_get_u32(tb[TCA_FQ_PIE_FLOWS]);
if (!q->flows_cnt || q->flows_cnt >= 65536) {
if (!q->flows_cnt || q->flows_cnt > 65536) {
NL_SET_ERR_MSG_MOD(extack,
"Number of flows must range in [1..65535]");
"Number of flows must range in [1..65536]");
goto flow_error;
}
}
@ -367,7 +367,7 @@ static void fq_pie_timer(struct timer_list *t)
struct fq_pie_sched_data *q = from_timer(q, t, adapt_timer);
struct Qdisc *sch = q->sch;
spinlock_t *root_lock; /* to lock qdisc for probability calculations */
u16 idx;
u32 idx;
root_lock = qdisc_lock(qdisc_root_sleeping(sch));
spin_lock(root_lock);
@ -388,7 +388,7 @@ static int fq_pie_init(struct Qdisc *sch, struct nlattr *opt,
{
struct fq_pie_sched_data *q = qdisc_priv(sch);
int err;
u16 idx;
u32 idx;
pie_params_init(&q->p_params);
sch->limit = 10 * 1024;
@ -500,7 +500,7 @@ static int fq_pie_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
static void fq_pie_reset(struct Qdisc *sch)
{
struct fq_pie_sched_data *q = qdisc_priv(sch);
u16 idx;
u32 idx;
INIT_LIST_HEAD(&q->new_flows);
INIT_LIST_HEAD(&q->old_flows);

8
tools/testing/selftests/tc-testing/tc-tests/qdiscs/fq_pie.json
View File

@ -9,11 +9,11 @@
"setup": [
"$IP link add dev $DUMMY type dummy || /bin/true"
],
"cmdUnderTest": "$TC qdisc add dev $DUMMY root fq_pie flows 65536",
"expExitCode": "2",
"cmdUnderTest": "$TC qdisc add dev $DUMMY handle 1: root fq_pie flows 65536",
"expExitCode": "0",
"verifyCmd": "$TC qdisc show dev $DUMMY",
"matchPattern": "qdisc",
"matchCount": "0",
"matchPattern": "qdisc fq_pie 1: root refcnt 2 limit 10240p flows 65536",
"matchCount": "1",
"teardown": [
"$IP link del dev $DUMMY"
]