From: Jakub Kicinski <kuba@kernel.org>
To: madhuparnabhowmik10@gmail.com
Cc: davem@davemloft.net, kuznet@ms2.inr.ac.ru,
yoshfuji@linux-ipv6.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, sfr@canb.auug.org.au,
frextrite@gmail.com, joel@joelfernandes.org, paulmck@kernel.org,
cai@lca.pw
Subject: Re: [PATCH net] ipv6: Fix suspicious RCU usage warning in ip6mr
Date: Thu, 14 May 2020 09:40:08 -0700 [thread overview]
Message-ID: <20200514094008.6421ea71@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200514070204.3108-1-madhuparnabhowmik10@gmail.com>
On Thu, 14 May 2020 12:32:04 +0530 madhuparnabhowmik10@gmail.com wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
> This patch fixes the following warning:
>
> =============================
> WARNING: suspicious RCU usage
> 5.7.0-rc4-next-20200507-syzkaller #0 Not tainted
> -----------------------------
> net/ipv6/ip6mr.c:124 RCU-list traversed in non-reader section!!
>
> ipmr_new_table() returns an existing table, but there is no table at
> init. Therefore the condition: either holding rtnl or the list is empty
> is used.
>
> Fixes: d13fee049f ("Default enable RCU list lockdep debugging with .."): WARNING: suspicious RCU usage
Fixes tag: Fixes: d13fee049f ("Default enable RCU list lockdep debugging with .."): WARNING: suspicious RCU usage
Has these problem(s):
- Target SHA1 does not exist
I think the message at the end is confusing automation, could you use
the standard Fixes tag format, please?
> Reported-by: kernel test robot <lkp@intel.com>
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
> ---
> net/ipv6/ip6mr.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
> index 65a54d74acc1..fbe282bb8036 100644
> --- a/net/ipv6/ip6mr.c
> +++ b/net/ipv6/ip6mr.c
> @@ -98,7 +98,7 @@ static void ipmr_expire_process(struct timer_list *t);
> #ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
> #define ip6mr_for_each_table(mrt, net) \
> list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list, \
> - lockdep_rtnl_is_held())
> + lockdep_rtnl_is_held() || list_empty(&net->ipv6.mr6_tables))
double space, line over 80 chars
> static struct mr_table *ip6mr_mr_table_iter(struct net *net,
> struct mr_table *mrt)
Other than these nits looks good, thanks!
next prev parent reply other threads:[~2020-05-14 16:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-14 7:02 [PATCH net] ipv6: Fix suspicious RCU usage warning in ip6mr madhuparnabhowmik10
2020-05-14 16:40 ` Jakub Kicinski [this message]
2020-05-15 17:32 ` Madhuparna Bhowmik
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