From: Pavel Skripkin <paskripkin@gmail.com>
To: Haakon Bugge <haakon.bugge@oracle.com>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>,
"David S. Miller" <davem@davemloft.net>,
"kuba@kernel.org" <kuba@kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
OFED mailing list <linux-rdma@vger.kernel.org>,
"rds-devel@oss.oracle.com" <rds-devel@oss.oracle.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com"
<syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com>
Subject: Re: [PATCH] net: rds: fix memory leak in rds_recvmsg
Date: Tue, 8 Jun 2021 11:00:06 +0300 [thread overview]
Message-ID: <20210608110006.5dbca106@gmail.com> (raw)
In-Reply-To: <CF68E17D-CC8A-4B30-9B67-4A0B0047FCE1@oracle.com>
On Tue, 8 Jun 2021 07:11:27 +0000
Haakon Bugge <haakon.bugge@oracle.com> wrote:
>
>
> > On 7 Jun 2021, at 21:41, Pavel Skripkin <paskripkin@gmail.com>
> > wrote:
> >
> > Syzbot reported memory leak in rds. The problem
> > was in unputted refcount in case of error.
> >
> > int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t
> > size, int msg_flags)
> > {
> > ...
> >
> > if (!rds_next_incoming(rs, &inc)) {
> > ...
> > }
> >
> > After this "if" inc refcount incremented and
> >
> > if (rds_cmsg_recv(inc, msg, rs)) {
> > ret = -EFAULT;
> > goto out;
> > }
> > ...
> > out:
> > return ret;
> > }
> >
> > in case of rds_cmsg_recv() fail the refcount won't be
> > decremented. And it's easy to see from ftrace log, that
> > rds_inc_addref() don't have rds_inc_put() pair in
> > rds_recvmsg() after rds_cmsg_recv()
> >
> > 1) | rds_recvmsg() {
> > 1) 3.721 us | rds_inc_addref();
> > 1) 3.853 us | rds_message_inc_copy_to_user();
> > 1) + 10.395 us | rds_cmsg_recv();
> > 1) + 34.260 us | }
> >
> > Fixes: bdbe6fbc6a2f ("RDS: recv.c")
> > Reported-and-tested-by:
> > syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com
> > Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
>
> Thank for your commit and analyses. One small nit below.
>
> > ---
> > net/rds/recv.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/rds/recv.c b/net/rds/recv.c
> > index 4db109fb6ec2..3fa16c339bfe 100644
> > --- a/net/rds/recv.c
> > +++ b/net/rds/recv.c
> > @@ -714,7 +714,7 @@ int rds_recvmsg(struct socket *sock, struct
> > msghdr *msg, size_t size,
> >
> > if (rds_cmsg_recv(inc, msg, rs)) {
> > ret = -EFAULT;
> > - goto out;
> > + goto out_put;
>
> Would a simple "break;" do it here and no need for the next hunk?
>
>
> Thxs, Håkon
>
Sure! I'll send v2 soon. Thank you for feedback :)
With regards,
Pavel Skripkin
next prev parent reply other threads:[~2021-06-08 8:00 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-07 19:41 [PATCH] net: rds: fix memory leak in rds_recvmsg Pavel Skripkin
2021-06-08 7:11 ` Haakon Bugge
2021-06-08 8:00 ` Pavel Skripkin [this message]
2021-06-08 8:06 ` [PATCH v2] " Pavel Skripkin
2021-06-08 12:29 ` Haakon Bugge
2021-06-08 14:41 ` Santosh Shilimkar
2021-06-08 23:40 ` patchwork-bot+netdevbpf
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