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Message-ID: <1335965318.22133.568.camel@edumazet-glaptop>
Date: Wed, 02 May 2012 15:28:38 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: Sasha Levin <levinsasha928@...il.com>
Cc: davem@...emloft.net, jchapman@...alix.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, davej@...hat.com
Subject: Re: [PATCH] net: l2tp: unlock socket lock before returning from
l2tp_ip_sendmsg
On Wed, 2012-05-02 at 15:10 +0200, Sasha Levin wrote:
> l2tp_ip_sendmsg could return without releasing socket lock, making it all the
> way to userspace, and generating the following warning:
>
> [ 130.891594] ================================================
> [ 130.894569] [ BUG: lock held when returning to user space! ]
> [ 130.897257] 3.4.0-rc5-next-20120501-sasha #104 Tainted: G W
> [ 130.900336] ------------------------------------------------
> [ 130.902996] trinity/8384 is leaving the kernel with locks still held!
> [ 130.906106] 1 lock held by trinity/8384:
> [ 130.907924] #0: (sk_lock-AF_INET){+.+.+.}, at: [<ffffffff82b9503f>] l2tp_ip_sendmsg+0x2f/0x550
>
> Signed-off-by: Sasha Levin <levinsasha928@...il.com>
> ---
> net/l2tp/l2tp_ip.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
> index 585d93e..a4d8364 100644
> --- a/net/l2tp/l2tp_ip.c
> +++ b/net/l2tp/l2tp_ip.c
> @@ -442,8 +442,10 @@ static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
>
> daddr = lip->l2tp_addr.s_addr;
> } else {
> - if (sk->sk_state != TCP_ESTABLISHED)
> - return -EDESTADDRREQ;
> + if (sk->sk_state != TCP_ESTABLISHED) {
> + rc = -EDESTADDRREQ;
> + goto out;
> + }
>
> daddr = inet->inet_daddr;
> connected = 1;
Good catch, but please use existing code style in this function.
rc = -EDESTADDRREQ;
if (sk->sk_state != TCP_ESTABLISHED)
goto out;
Also, please add in your commit message bug origin to ease stable team
work (not counting reviewers work)
Bug added in commit 2f16270f41e1 (l2tp: Fix locking in l2tp_ip.c)
Really, given the amount of patches you already sent, you should already
know that.
Thanks
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