On 2014-09-10 01:48:06 +0200, Andres Freund wrote: > On 2014-09-09 15:43:55 -0700, Cong Wang wrote: > > On Mon, Sep 8, 2014 at 2:25 PM, Andres Freund <and...@anarazel.de> wrote: > > > Hi, > > > > > > (don't have netdev archived, thus answering here, sorry) > > > > > > On 2014-09-07 16:41:09 -0700, David Miller wrote: > > >> Alexander Y. Fomichev (1): > > >> net: prevent of emerging cross-namespace symlinks > > > > > > > Since you are quoting this change, are you saying it causes > > the following kernel warning? > > I thought it might be a likely candidate; but I'm not sure at all. I'll > verify it as soon as I can reboot the machine a couple of times (end of > week-ish). > > > > I'm seeing WARNINGs like: > > > [ 1005.269134] ------------[ cut here ]------------ > > > [ 1005.269148] WARNING: CPU: 6 PID: 4213 at fs/sysfs/dir.c:31 > > > sysfs_warn_dup+0x64/0x80() > > > [ 1005.269150] sysfs: cannot create duplicate filename > > > '/devices/pci0000:00/0000:00:1c.4/0000:03:00.0/net/eth0/upper_mv-eth0' > > > > > > Is there a network device named upper_mv-eth0 existed in your system > > before you created macvlan? > > No, there wasn't any. Afaics, the sequence is: > 1) macvlan mv-eth0 is created in global namespace > 2) mv-eth0 is moved (by systemd-nsspawn) into a new network > namespace. Leaving a dangling symlink in the host namespace > /devices/pci0000:00/0000:00:1c.4/0000:03:00.0/net/eth0/upper_mv-eth0 pointing > toward > ../mv-eth0 > which doesn't exist in the external namespace. The new namespace seems > to have broken 'lower_bond0' symlink as well > > This seems to be the case (and probably the actual root cause) in > slightly earlier kernels as well. > What changed seems to be that: > 3) macvlan mv-eth0 is destroyed in the namespace (potentially while > tearing it down) > 4) Now there's a broken symlink that doesn't make sense in any namespace > 5) mv-eth0 can't be created anew > > It seems that 3-5 didn't happen that way on older kernels. The most > recent where it's not persistently broken is 3.16.0-rc7-00007 - > 31dab719f. The oldest where I know it's reproducible is > 3.17.0-rc4-andres-00135-g35af256.
I've reproduced the problem on another machine where it's perfectly reproducible (except being about mv-bond0). After reverting only the aforementioned 4c75431ac352063 it works again. As I said above, I'm not sure whether 4c75431ac352063 is the actual culprit, but it certainly made the problem visible. How are these upper_$if/lower_$if supposed to behave when the macvlan and the underlying device are in differing namespaces? Greetings, Andres Freund -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
