From: Davide Caratti <dcaratti@xxxxxxxxxx> commit 3a62fed2fd7b6fea96d720e779cafc30dfb3a22e upstream. 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 bb2f930d6dd708469a587dc9ed1efe1ef969c0bf. [1] https://lore.kernel.org/netdev/20210407163808.499027-1-colin.king@xxxxxxxxxxxxx/ CC: Colin Ian King <colin.king@xxxxxxxxxxxxx> CC: stable@xxxxxxxxxxxxxxx Fixes: bb2f930d6dd7 ("net/sched: fix infinite loop in sch_fq_pie") Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler") Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/sch_fq_pie.c | 10 +++++----- tools/testing/selftests/tc-testing/tc-tests/qdiscs/fq_pie.json | 8 ++++---- 2 files changed, 9 insertions(+), 9 deletions(-) --- a/net/sched/sch_fq_pie.c +++ b/net/sched/sch_fq_pie.c @@ -297,9 +297,9 @@ static int fq_pie_change(struct Qdisc *s 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_li 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 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 Qdis 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); --- a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/fq_pie.json +++ b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/fq_pie.json @@ -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" ]
