lkml.org 
[lkml]   [2019]   [Sep]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.2 017/124] net_sched: let qdisc_put() accept NULL pointer
    Date
    From: Cong Wang <xiyou.wangcong@gmail.com>

    [ 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>
    ---
    net/sched/sch_generic.c | 3 +++
    1 file changed, 3 insertions(+)

    --- a/net/sched/sch_generic.c
    +++ b/net/sched/sch_generic.c
    @@ -985,6 +985,9 @@ static void qdisc_destroy(struct Qdisc *

    void qdisc_put(struct Qdisc *qdisc)
    {
    + if (!qdisc)
    + return;
    +
    if (qdisc->flags & TCQ_F_BUILTIN ||
    !refcount_dec_and_test(&qdisc->refcnt))
    return;

    \
     
     \ /
      Last update: 2019-09-20 00:07    [W:4.018 / U:0.164 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site