lkml.org 
[lkml]   [2021]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 73/74] net_sched: fix a crash in tc_new_tfilter()
    Date
    From: Cong Wang <xiyou.wangcong@gmail.com>

    commit 460b360104d51552a57f39e54b2589c9fd7fa0b3 upstream.

    When tcf_block_find() fails, it already rollbacks the qdisc refcnt,
    so its caller doesn't need to clean up this again. Avoid calling
    qdisc_put() again by resetting qdisc to NULL for callers.

    Reported-by: syzbot+37b8770e6d5a8220a039@syzkaller.appspotmail.com
    Fixes: e368fdb61d8e ("net: sched: use Qdisc rcu API instead of relying on rtnl lock")
    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/cls_api.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    --- a/net/sched/cls_api.c
    +++ b/net/sched/cls_api.c
    @@ -629,8 +629,10 @@ static struct tcf_block *tcf_block_find(
    errout_rcu:
    rcu_read_unlock();
    errout_qdisc:
    - if (*q)
    + if (*q) {
    qdisc_put(*q);
    + *q = NULL;
    + }
    return ERR_PTR(err);
    }


    \
     
     \ /
      Last update: 2021-12-13 11:10    [W:4.085 / U:0.100 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site