diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2019-09-12 10:22:30 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-21 07:19:38 +0200 |
| commit | 8e18aa20f4f0e5eb8688f6ab9250dfa83517c474 (patch) | |
| tree | 1f6348131cb43d3660aaf120a44f56eef9a23db2 | |
| parent | e0426ee9ad505871f8ed12bfd20d7d3ffbdbd241 (diff) | |
net_sched: let qdisc_put() accept NULL pointer
[ Upstream commit 6efb971ba8edfbd80b666f29de12882852f095ae ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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; |