lkml.org 
[lkml]   [2013]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: net: rcu warnings in ip6fl_get_first
On Fri, Feb 08, 2013 at 01:38:29AM +0000, Cong Wang wrote:
> On Thu, 07 Feb 2013 at 19:32 GMT, Sasha Levin <sasha.levin@oracle.com> wrote:
> > Hi guys,
> >
> > I got the following while fuzzing with trinity inside a KVM tools guest:
> >
> > [ 51.680236] ===============================
> > [ 51.681914] [ INFO: suspicious RCU usage. ]
> > [ 51.683610] 3.8.0-rc6-next-20130206-sasha-00028-g83214f7-dirty #276 Tainted: G W
> > [ 51.686703] -------------------------------
> > [ 51.688281] net/ipv6/ip6_flowlabel.c:671 suspicious rcu_dereference_check() usage!
> > [ 51.691345]
>
> It should use rcu_dereference_bh()...
>
> diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
> index ea42bf4..c50080f 100644
> --- a/net/ipv6/ip6_flowlabel.c
> +++ b/net/ipv6/ip6_flowlabel.c
> @@ -65,13 +65,13 @@ static DEFINE_SPINLOCK(ip6_fl_lock);
> static DEFINE_SPINLOCK(ip6_sk_fl_lock);
>
> #define for_each_fl_rcu(hash, fl) \
> - for (fl = rcu_dereference(fl_ht[(hash)]); \
> + for (fl = rcu_dereference_bh(fl_ht[(hash)]); \
> fl != NULL; \
> - fl = rcu_dereference(fl->next))
> + fl = rcu_dereference_hb(fl->next))

Small but important typo in the preceding line, should be:

+ fl = rcu_dereference_bh(fl->next))

Thanx, Paul

> #define for_each_fl_continue_rcu(fl) \
> - for (fl = rcu_dereference(fl->next); \
> + for (fl = rcu_dereference_bh(fl->next); \
> fl != NULL; \
> - fl = rcu_dereference(fl->next))
> + fl = rcu_dereference_bh(fl->next))
>
> #define for_each_sk_fl_rcu(np, sfl) \
> for (sfl = rcu_dereference_bh(np->ipv6_fl_list); \
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>



\
 
 \ /
  Last update: 2013-02-08 21:01    [W:0.516 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site