>>>> How cute... Same mountpoint in both, so these mount(2) will sometimes >>>> fail (cgroup picks the same sb on the same options, AFAICS) and fail >>>> silently due to these redirects... >>>> >>>> That's a lovely way to stress-test a large part of ro-bind stuff *and* >>>> umount()-related code. Could you do C equivalent of the above (just >>>> the same syscalls in loop, nothing fancier) and do time-stamped strace? >>>> >>> Sure, I'll write a C version and try to reproduce the warning. >>> >> Unfortunately, the C equivalent can't reproduce the warning, I've run the >> test for the whole night. :( While using the script, often I can trigger >> the warning in several mins. > > Ho-hum... I wonder if we are hitting cgroup_clone() in all that fun... I don't think so, I think cgroup_clone() will be called only if namespace is used, like clone(CLONE_NEWNS). Even if cgroup_clone() gets called, it will return before doing any vfs work unless the ns_cgroup subsystem is mounted. int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys, char *nodename) { ... mutex_lock(&cgroup_mutex); again: root = subsys->root; if (root == &rootnode) { <--- here mutex_unlock(&cgroup_mutex); return 0; } > Could you > a) add a printk to that sucker > b) independently from (a), see if wrapping these syscalls into > pid = fork(); > if (!pid) { > [make a syscall, print something] > exit(0); > } else if (pid > 0) { > waitpid(pid, NULL, 0); > } > and see what happens... > > _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers