From: Zhengchao Shao shaozhengchao@huawei.com
[ Upstream commit 2a3fc78210b9f0e85372a2435368962009f480fc ]
When the default qdisc is sfb, if the qdisc of dev_queue fails to be inited during mqprio_init(), sfb_reset() is invoked to clear resources. In this case, the q->qdisc is NULL, and it will cause gpf issue.
The process is as follows: qdisc_create_dflt() sfb_init() tcf_block_get() --->failed, q->qdisc is NULL ... qdisc_put() ... sfb_reset() qdisc_reset(q->qdisc) --->q->qdisc is NULL ops = qdisc->ops
The following is the Call Trace information: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] RIP: 0010:qdisc_reset+0x2b/0x6f0 Call Trace: <TASK> sfb_reset+0x37/0xd0 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: 0033:0x7f2164122d04 </TASK>
Fixes: e13e02a3c68d ("net_sched: SFB flow scheduler") Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/sched/sch_sfb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c index 0e1cb517b0d9..9ded56228ea1 100644 --- a/net/sched/sch_sfb.c +++ b/net/sched/sch_sfb.c @@ -455,7 +455,8 @@ static void sfb_reset(struct Qdisc *sch) { struct sfb_sched_data *q = qdisc_priv(sch);
- qdisc_reset(q->qdisc); + if (likely(q->qdisc)) + qdisc_reset(q->qdisc); q->slot = 0; q->double_buffering = false; sfb_zero_all_buckets(q);