On Thu, Feb 12, 2009 at 02:54:58PM +0800, Li Zefan wrote: > But the following testcase can also trigger the warning: > > thread 1: > for ((; ;)) > { > mount -t cgroup -o ns xxx cgroup/ > /dev/null 2>&1 > # remove the dirs generated by cgroup_clone() > rmdir cgroup/[1-9]* > /dev/null 2>&1 > umount cgroup/ > /dev/null 2>&1 > } > > > thread 2: > > int foo(void *arg) > { return 0; } > > char *stack[4096]; > > int main(int argc, char **argv) > { > int usec = DEFAULT_USEC; > while (1) { > usleep(usec); > # cgroup_clone() will be called > clone(foo, stack+4096, CLONE_NEWNS, NULL); > } > > return 0; > } Uh-oh... That clone() will do more, actually - it will clone a bunch of vfsmounts. What happens if you create a separate namespace for the first thread, so that the second one would not have our vfsmount to play with? Alternatively, what if the second thread is doing mount --bind cgroup foo umount foo in a loop? Another one: does turning the umount in the first thread into umount -l affect anything? _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers