From: Cong Wang xiyou.wangcong@gmail.com
[ Upstream commit 306381aec7c2b5a658eebca008c8a1b666536cba ]
When tcf_block_get() fails inside atm_tc_init(), atm_tc_put() is called to release the qdisc p->link.q. But the flow->ref prevents it to do so, as the flow->ref is still zero.
Fix this by moving the p->link.ref initialization before tcf_block_get().
Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure") Reported-and-tested-by: syzbot+d411cff6ab29cc2c311b@syzkaller.appspotmail.com Cc: Jamal Hadi Salim jhs@mojatatu.com Cc: Jiri Pirko jiri@resnulli.us Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/sch_atm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/net/sched/sch_atm.c +++ b/net/sched/sch_atm.c @@ -545,15 +545,15 @@ static int atm_tc_init(struct Qdisc *sch if (!p->link.q) p->link.q = &noop_qdisc; pr_debug("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q); + p->link.vcc = NULL; + p->link.sock = NULL; + p->link.common.classid = sch->handle; + p->link.ref = 1;
err = tcf_block_get(&p->link.block, &p->link.filter_list); if (err) return err;
- p->link.vcc = NULL; - p->link.sock = NULL; - p->link.common.classid = sch->handle; - p->link.ref = 1; tasklet_init(&p->task, sch_atm_dequeue, (unsigned long)sch); return 0; }