| Message ID | 1464112420-1722-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index 8d423bc..f876f70 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; }
This is a note to let you know that I have just added a patch titled net: bridge: fix old ioctl unlocked net device walk to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt11. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 0e76b4f688893c83a8331d76452d1c7ffd0d87f7 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Date: Wed, 4 May 2016 16:18:45 +0200 Subject: 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: Kamal Mostafa <kamal@canonical.com> --- net/bridge/br_ioctl.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) -- 2.7.4