Messages in this thread | | | Date | Tue, 5 Jul 2016 16:34:52 +0200 | From | Oleg Nesterov <> | Subject | Re: is pid_namespace leak in v3.10? |
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On 07/05, Xishi Qiu wrote: > > I find pid_namespace leak by "cat /proc/slabinfo | grep pid_namespace". > The kernel version is RHEL 7.1 (kernel v3.10 stable). > The following is the test case, after several times, the count of pid_namespace > become very large, is it correct?
Apparently not,
> I also test mainline, and the count will increase too, but it seems stably later.
And I can't reproduce the problem with the latest rhel7 kernel.
And just in case, I have no idea what actually slub reports as "active_objs" but certainly this is not the number of allocated "in use" objects, so it is fine if this counter doesn't go to zero when your test-case exits. But it should not grow "too much".
> BTW, this patch doesn't help. > 24c037ebf5723d4d9ab0996433cee4f96c292a4d > exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting
Sure, it can't help, your test-case doesn't fork other processes which could race with the exiting sub-namespace init.
> int main() > { > pid_t pid, child_pid; > int i, status; > void *stack; > > for (i = 0; i < 100; i++) { > stack = malloc(8192); > pid = clone(&test, (char *)stack + 8192, CLONE_NEWPID|SIGCHLD, 0); > } > > sleep(5);
is this sleep() really needed to trigger the problem?
Oleg.
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