diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2019-09-12 10:22:30 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-09-15 20:54:14 +0200 |
| commit | 6efb971ba8edfbd80b666f29de12882852f095ae (patch) | |
| tree | 81a0a8101c77ce22309bfd7e6a59b730e1bf47d6 /net/sched/sch_generic.c | |
| parent | 23426a25e55a417dc104df08781b6eff95e65f3f (diff) | |
| download | lwn-6efb971ba8edfbd80b666f29de12882852f095ae.tar.gz lwn-6efb971ba8edfbd80b666f29de12882852f095ae.zip | |
net_sched: let qdisc_put() accept NULL pointer
When tcf_block_get() fails in sfb_init(), q->qdisc is still a NULL
pointer which leads to a crash in sfb_destroy(). Similar for
sch_dsmark.
Instead of fixing each separately, Linus suggested to just accept
NULL pointer in qdisc_put(), which would make callers easier.
(For sch_dsmark, the bug probably exists long before commit
6529eaba33f0.)
Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
Reported-by: syzbot+d5870a903591faaca4ae@syzkaller.appspotmail.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_generic.c')
| -rw-r--r-- | net/sched/sch_generic.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index ac28f6a5d70e..17bd8f539bc7 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -985,6 +985,9 @@ static void qdisc_destroy(struct Qdisc *qdisc) void qdisc_put(struct Qdisc *qdisc) { + if (!qdisc) + return; + if (qdisc->flags & TCQ_F_BUILTIN || !refcount_dec_and_test(&qdisc->refcnt)) return; |