On Thu, 21 Sep 2006 14:42:22 +0100 Alex Zeffertt <ajz at cambridgebroadband.com> wrote: > Hi all, > > We use linux-2.4.20 in one of our products and we've found what looks > to be a problem in the bridge module. (I know this is old code but we > don't send our customers kernel upgrades unless we really have to!) > > The problem is that some of our bridges have become orphaned from the > bridge module. Specifically > > ifconfig ourbridgename > > shows that the device "ourbridgename" is known to the kernel, but > > brctl show > > does not list "ourbridgename". You need to find a sequence of commands that reproduces it. Unless you run multiple commands in parallel, I don't think there should be a problem with 2.4. > I've looked through the bridge module and it seems that the most likely > explanation is that bridge_list in br_if.c has become corrupted, causing > the bridge called "ourbridgename" to become orphaned. > > I cannot see how this would happen, however, since bridge_list is only > ever referenced under the ioctl_mutex. I should also point out that > br_del_bridge() is not called by our application. > > I noticed that in later kernels the ioctl_mutex has been replaced by > the rtnl_lock(). Why was this done? Could this be related to our > problem? In 2.6 it was observed that all changes to bridge list were already being done under the RT netlink mutex, so no additional locking was needed. -- Stephen Hemminger <shemminger at osdl.org>
