Re: [libvirt] [PATCH] LXC: make sure fuse thread start to run before we do clone

On Thu, Nov 07, 2013 at 09:15:43PM +0800, Gao feng wrote: > I met a problem that container blocked by seteuid/setegid > which is call in lxcContainerSetID on UP system and libvirt > compiled with --with-fuse=yes. > > I looked into the glibc's codes, and found setxid in glibc > calls futex() to wait for other threads to change their > setxid_futex to 0(see setxid_mark_thread in glibc). > > since the process created by clone system call will not > share the memory with the other threads and the context > of memory doesn't changed until we call execl.(COW) > > So if the process which created by clone is called before > fuse thread being stated, the new setxid_futex of fuse > thread will not be saw in this process, it will be blocked > forever. > > Maybe this problem should be fixed in glibc, but I send > this patch as a quick fix. Can you show a stack trace of the threads/processes deadlocking