aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorNikolay Aleksandrov <nikolay@cumulusnetworks.com>2016-05-04 16:18:45 +0200
committerSasha Levin <sasha.levin@oracle.com>2016-07-12 08:48:15 -0400
commitf7eadcefc08424765cad28feddd6659e05c1b2c8 (patch)
treefe736114fe495a1ab32ec370a5ab854505c8f70b
parente79fd7106c1555ac38d915ecb3903f1a92860e91 (diff)
downloadlinux-linaro-stable-f7eadcefc08424765cad28feddd6659e05c1b2c8.tar.gz
net: bridge: fix old ioctl unlocked net device walk
[ Upstream commit 31ca0458a61a502adb7ed192bf9716c6d05791a5 ] get_bridge_ifindices() is used from the old "deviceless" bridge ioctl calls which aren't called with rtnl held. The comment above says that it is called with rtnl but that is not really the case. Here's a sample output from a test ASSERT_RTNL() which I put in get_bridge_ifindices and executed "brctl show": [ 957.422726] RTNL: assertion failed at net/bridge//br_ioctl.c (30) [ 957.422925] CPU: 0 PID: 1862 Comm: brctl Tainted: G W O 4.6.0-rc4+ #157 [ 957.423009] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014 [ 957.423009] 0000000000000000 ffff880058adfdf0 ffffffff8138dec5 0000000000000400 [ 957.423009] ffffffff81ce8380 ffff880058adfe58 ffffffffa05ead32 0000000000000001 [ 957.423009] 00007ffec1a444b0 0000000000000400 ffff880053c19130 0000000000008940 [ 957.423009] Call Trace: [ 957.423009] [<ffffffff8138dec5>] dump_stack+0x85/0xc0 [ 957.423009] [<ffffffffa05ead32>] br_ioctl_deviceless_stub+0x212/0x2e0 [bridge] [ 957.423009] [<ffffffff81515beb>] sock_ioctl+0x22b/0x290 [ 957.423009] [<ffffffff8126ba75>] do_vfs_ioctl+0x95/0x700 [ 957.423009] [<ffffffff8126c159>] SyS_ioctl+0x79/0x90 [ 957.423009] [<ffffffff8163a4c0>] entry_SYSCALL_64_fastpath+0x23/0xc1 Since it only reads bridge ifindices, we can use rcu to safely walk the net device list. Also remove the wrong rtnl comment above. Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--net/bridge/br_ioctl.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c
index 8d423bc649b9..f876f707fd9e 100644
--- a/net/bridge/br_ioctl.c
+++ b/net/bridge/br_ioctl.c
@@ -21,18 +21,19 @@
#include <asm/uaccess.h>
#include "br_private.h"
-/* called with RTNL */
static int get_bridge_ifindices(struct net *net, int *indices, int num)
{
struct net_device *dev;
int i = 0;
- for_each_netdev(net, dev) {
+ rcu_read_lock();
+ for_each_netdev_rcu(net, dev) {
if (i >= num)
break;
if (dev->priv_flags & IFF_EBRIDGE)
indices[i++] = dev->ifindex;
}
+ rcu_read_unlock();
return i;
}