On Sat, 2011-08-27 at 12:38 +0200, Dirk Weinhardt wrote: > Package: linux-2.6 > Version: 2.6.39-3~bpo60+1 > Severity: normal > > > I am experiencing the following issue with a Debian squeeze based > server and the most recent squeeze-backports kernel: > > I realized that some vstfpd daemons randomly drop connections (sending > a FIN right after the initial TCP hand shake was completed). > Furthermore, a "Failed to create cgroup nnnn: -17" message is logged > by the kernel. > > Furthermore, I am observing a steadily increasing number of > directories named like pids being created in the root of the cgroup > virtual filesystem (mounted at /cgroup). For each connection attempt > to a vsftpd daemon a new directory is created. Those directories seem > to be never deleted. After a few days of uptime there are about 7,500 > directories while there constantly are only about 150 processes > running (more or less idling, this server usually has low load). Do they persist if you restart vsftpd? > When stracing vsftpd the call that fails seems to be this one (full > output below): > > clone(child_stack=0, flags=0x28000000|SIGCHLD) = -1 EEXIST (File > exists) > > Which makes me believe that those "zombie directories" in /cgroup > might conflict with the new pid . The longer the server is up the more > likely it becomes that connections are dropped. > > Side note: The affected vsftpd daemons are running on a server that > also is hosting an LXC-based virtual server. I have experienced a > steadily increasing soft IRQ load on the server while a cgroup virtual > filesystem being mounted. I have upgraded to the recent > squeeze-backports kernel which seems not to suffer from this soft IRQ > issue. [...] That is bug #629373. Ben.
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