[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <Y2a+eXr20BcI3JDe@pop-os.localdomain>
Date: Sat, 5 Nov 2022 12:50:17 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: Hawkins Jiawei <yin31149@...il.com>
Cc: Jamal Hadi Salim <jhs@...atatu.com>, Jiri Pirko <jiri@...nulli.us>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
syzbot+232ebdbd36706c965ebf@...kaller.appspotmail.com,
syzkaller-bugs@...glegroups.com, 18801353760@....com,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: sched: fix memory leak in tcindex_set_parms
On Mon, Oct 31, 2022 at 02:08:35PM +0800, Hawkins Jiawei wrote:
> Syzkaller reports a memory leak as follows:
> ====================================
> BUG: memory leak
> unreferenced object 0xffff88810c287f00 (size 256):
> comm "syz-executor105", pid 3600, jiffies 4294943292 (age 12.990s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff814cf9f0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
> [<ffffffff839c9e07>] kmalloc include/linux/slab.h:576 [inline]
> [<ffffffff839c9e07>] kmalloc_array include/linux/slab.h:627 [inline]
> [<ffffffff839c9e07>] kcalloc include/linux/slab.h:659 [inline]
> [<ffffffff839c9e07>] tcf_exts_init include/net/pkt_cls.h:250 [inline]
> [<ffffffff839c9e07>] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342
> [<ffffffff839caa1f>] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553
> [<ffffffff8394db62>] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147
> [<ffffffff8389e91c>] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082
> [<ffffffff839eba67>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540
> [<ffffffff839eab87>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
> [<ffffffff839eab87>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345
> [<ffffffff839eb046>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921
> [<ffffffff8383e796>] sock_sendmsg_nosec net/socket.c:714 [inline]
> [<ffffffff8383e796>] sock_sendmsg+0x56/0x80 net/socket.c:734
> [<ffffffff8383eb08>] ____sys_sendmsg+0x178/0x410 net/socket.c:2482
> [<ffffffff83843678>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536
> [<ffffffff838439c5>] __sys_sendmmsg+0x105/0x330 net/socket.c:2622
> [<ffffffff83843c14>] __do_sys_sendmmsg net/socket.c:2651 [inline]
> [<ffffffff83843c14>] __se_sys_sendmmsg net/socket.c:2648 [inline]
> [<ffffffff83843c14>] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648
> [<ffffffff84605fd5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> [<ffffffff84605fd5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
> ====================================
>
> Kernel will uses tcindex_change() to change an existing
> traffic-control-indices filter properties. During the
> process of changing, kernel will clears the old
> traffic-control-indices filter result, and updates it
> by RCU assigning new traffic-control-indices data.
>
> Yet the problem is that, kernel will clears the old
> traffic-control-indices filter result, without destroying
> its tcf_exts structure, which triggers the above
> memory leak.
>
> This patch solves it by using tcf_exts_destroy() to
> destroy the tcf_exts structure in old
> traffic-control-indices filter result.
So... your patch can be just the following one-liner, right?
diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 1c9eeb98d826..00a6c04a4b42 100644
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -479,6 +479,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
}
if (old_r && old_r != r) {
+ tcf_exts_destroy(&old_r->exts);
err = tcindex_filter_result_init(old_r, cp, net);
if (err < 0) {
kfree(f);
Powered by blists - more mailing lists