Re: [tipc-discussion] [PATCH v2 3/3] tipc: fix issue of calling smp_processor_id() in preemptible

[Jon M. <jm...@re...>]

On 2/20/20 10:44 AM, Xin Long wrote:
> On Wed, Feb 19, 2020 at 4:34 PM Dmitry Vyukov <dv...@go...> wrote:
>> On Wed, Feb 19, 2020 at 9:29 AM Dmitry Vyukov <dv...@go...> wrote:
>>> On Mon, Aug 12, 2019 at 9:44 AM Ying Xue <yin...@wi...> wrote:
>>>> syzbot found the following issue:
>>>>
>>>> [   81.119772][ T8612] BUG: using smp_processor_id() in preemptible [00000000] code: syz-executor834/8612
>>>> [   81.136212][ T8612] caller is dst_cache_get+0x3d/0xb0
>>>> [   81.141450][ T8612] CPU: 0 PID: 8612 Comm: syz-executor834 Not tainted 5.2.0-rc6+ #48
[...]
>>>> Fixes: e9c1a793210f ("tipc: add dst_cache support for udp media")
>>>> Reported-by: syz...@sy...
>>>> Signed-off-by: Hillf Danton <hd...@si...>
>>>> Signed-off-by: Ying Xue <yin...@wi...>
>>> Hi,
>>>
>>> Was this ever merged?
>>> The bug is still open, alive and kicking:
>>> https://syzkaller.appspot.com/bug?extid=1a68504d96cd17b33a05
>>>
>>> and one of the top crashers currently.
>>> Along with few other top crashers, these bugs prevent most of the
>>> other kernel testing from happening.
>> /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
>>
>> +jmaloy new email address

Acked-by: Jon Maloy <jm...@re...>


>>
>>>> ---
>>>>   net/tipc/udp_media.c | 12 +++++++++---
>>>>   1 file changed, 9 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
>>>> index 287df687..ca3ae2e 100644
>>>> --- a/net/tipc/udp_media.c
>>>> +++ b/net/tipc/udp_media.c
>>>> @@ -224,6 +224,8 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
>>>>          struct udp_bearer *ub;
>>>>          int err = 0;
>>>>
>>>> +       local_bh_disable();
>>>> +
>>>>          if (skb_headroom(skb) < UDP_MIN_HEADROOM) {
>>>>                  err = pskb_expand_head(skb, UDP_MIN_HEADROOM, 0, GFP_ATOMIC);
>>>>                  if (err)
>>>> @@ -237,9 +239,12 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
>>>>                  goto out;
>>>>          }
>>>>
>>>> -       if (addr->broadcast != TIPC_REPLICAST_SUPPORT)
>>>> -               return tipc_udp_xmit(net, skb, ub, src, dst,
>>>> -                                    &ub->rcast.dst_cache);
>>>> +       if (addr->broadcast != TIPC_REPLICAST_SUPPORT) {
>>>> +               err = tipc_udp_xmit(net, skb, ub, src, dst,
>>>> +                                   &ub->rcast.dst_cache);
>>>> +               local_bh_enable();
>>>> +               return err;
>>>> +       }
>>>>
>>>>          /* Replicast, send an skb to each configured IP address */
>>>>          list_for_each_entry_rcu(rcast, &ub->rcast.list, list) {
>>>> @@ -259,6 +264,7 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
>>>>          err = 0;
>>>>   out:
>>>>          kfree_skb(skb);
>>>> +       local_bh_enable();
>>>>          return err;
>>>>   }
>>>>
>>>> --
>>>> 2.7.4
>>>>
>>>> --
>>>> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send an email to syz...@go....
>>>> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/1565595162-1383-4-git-send-email-ying.xue%40windriver.com.