Commit f5ffa3b1 authored by Zhengchao Shao's avatar Zhengchao Shao Committed by David S. Miller
Browse files

Revert "net: sched: fq_codel: remove redundant resource cleanup in fq_codel_init()" 



This reverts commit 494f5063.

When the default qdisc is fq_codel, if the qdisc of dev_queue fails to be
inited during mqprio_init(), fq_codel_reset() is invoked to clear
resources. In this case, the flow is NULL, and it will cause gpf issue.

The process is as follows:
qdisc_create_dflt()
	fq_codel_init()
		...
		q->flows_cnt = 1024;
		...
		q->flows = kvcalloc(...)      --->failed, q->flows is NULL
	...
	qdisc_put()
		...
		fq_codel_reset()
			...
			flow = q->flows + i   --->q->flows is NULL

The following is the Call Trace information:
general protection fault, probably for non-canonical address
0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
RIP: 0010:fq_codel_reset+0x14d/0x350
Call Trace:
<TASK>
qdisc_reset+0xed/0x6f0
qdisc_destroy+0x82/0x4c0
qdisc_put+0x9e/0xb0
qdisc_create_dflt+0x2c3/0x4a0
mqprio_init+0xa71/0x1760
qdisc_create+0x3eb/0x1000
tc_modify_qdisc+0x408/0x1720
rtnetlink_rcv_msg+0x38e/0xac0
netlink_rcv_skb+0x12d/0x3a0
netlink_unicast+0x4a2/0x740
netlink_sendmsg+0x826/0xcc0
sock_sendmsg+0xc5/0x100
____sys_sendmsg+0x583/0x690
___sys_sendmsg+0xe8/0x160
__sys_sendmsg+0xbf/0x160
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fd272b22d04
</TASK>

Signed-off-by: default avatarZhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 51f9a892

net/sched/sch_fq_codel.c

+17 −8
Original line number Diff line number Diff line
@@ -478,24 +478,26 @@ static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt, 
	if (opt) {

		err = fq_codel_change(sch, opt, extack);

		if (err)

			return err;

			goto init_failure;

	}



	err = tcf_block_get(&q->block, &q->filter_list, sch, extack);

	if (err)

		return err;

		goto init_failure;



	if (!q->flows) {

		q->flows = kvcalloc(q->flows_cnt,

				    sizeof(struct fq_codel_flow),

				    GFP_KERNEL);

		if (!q->flows)

			return -ENOMEM;



		if (!q->flows) {

			err = -ENOMEM;

			goto init_failure;

		}

		q->backlogs = kvcalloc(q->flows_cnt, sizeof(u32), GFP_KERNEL);

		if (!q->backlogs)

			return -ENOMEM;



		if (!q->backlogs) {

			err = -ENOMEM;

			goto alloc_failure;

		}

		for (i = 0; i < q->flows_cnt; i++) {

			struct fq_codel_flow *flow = q->flows + i;
@@ -508,6 +510,13 @@ static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt, 
	else

		sch->flags &= ~TCQ_F_CAN_BYPASS;

	return 0;



alloc_failure:

	kvfree(q->flows);

	q->flows = NULL;

init_failure:

	q->flows_cnt = 0;

	return err;

}



static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)