Messages in this thread | | | Date | Fri, 13 Feb 2009 14:12:13 +0800 | From | Li Zefan <> | Subject | Re: [cgroup or VFS ?] WARNING: at fs/namespace.c:636 mntput_no_expire+0xac/0xf2() |
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Al Viro wrote: > On Fri, Feb 13, 2009 at 01:09:17PM +0800, Li Zefan wrote: > >> I ran following testcase, and triggered the warning in 1 hour: >> >> thread 1: >> for ((; ;)) >> { >> mount --bind /cgroup /mnt > /dev/null 2>&1 >> umount /mnt > /dev/null 2>&1 >> } >> >> tread 2: >> for ((; ;)) >> { >> mount -t cgroup -o cpu xxx /cgroup > /dev/null 2>&1 >> mkdir /cgroup/0 > /dev/null 2>&1 >> rmdir /cgroup/0 > /dev/null 2>&1 >> umount -l /cgroup > /dev/null 2>&1 >> } > > Wow. You know, at that point these redirects could probably be removed.
Ah, yes.
> If anything in there ends up producing an output, we very much want to > see that. Actually, I'd even make that > mount --bind /cgroup/mnt || (echo mount1: ; date) > etc., so we'd see when do they fail and which one fails (if any)... > > Which umount has failed in the above, BTW? > >
the first one sometimes failed, and the second one hasn't failed:
mount: wrong fs type, bad option, bad superblock on /cgroup, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so
mount1 Fri Feb 13 14:05:37 CST 2009 umount: /mnt: not mounted mount: wrong fs type, bad option, bad superblock on /cgroup, ...
mount1 Fri Feb 13 14:08:34 CST 2009 umount: /mnt: not mounted mount: wrong fs type, bad option, bad superblock on /cgroup, ...
mount1 Fri Feb 13 14:08:43 CST 2009 umount: /mnt: not mounted mount: wrong fs type, bad option, bad superblock on /cgroup, ...
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