Messages in this thread | | | Date | Mon, 17 Oct 2011 15:20:27 +0800 | From | Li Zefan <> | Subject | Re: BUG: cgroup_task_counter subsys may crash with whole-threadgroup move |
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08:09, Ben Blum wrote: > I was testing some patches for cgroup_attach_proc and managed to cause a > crash with the following usage pattern: > > mount -t cgroup none -o tasks /dev/cgroup > cd /dev/cgroup > mkdir foo > echo $PID > foo/cgroup.procs > echo $PID > tasks > echo $PID > foo/cgroup.procs > > Where $PID is the thread ID of a member of a multithreaded process (my > test program just does CLONE_THREAD 8 times and then all threads sleep). > (It doesn't matter if the thread is the group leader or not, but a > single-threaded process doesn't crash.) > > And get the following kernel panic: > http://maximegalon.andrew.cmu.edu/cgroup-taskstats/panic.txt > > It's deterministic, and happens only when the "tasks" subsystem is > mounted. > > I'm using user-mode linux to test, with the following config: > http://maximegalon.andrew.cmu.edu/cgroup-taskstats/config.txt > > and I ran it in GDB to get the following backtrace: > http://maximegalon.andrew.cmu.edu/cgroup-taskstats/bt.txt >
I've figured out what's wrong. Patch will be sent out soon.
Thanks for reporting this!
-- Li Zefan
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