On Thu, Nov 22, 2018 at 04:11:45PM +0100, Florian Weimer wrote: > * Mathieu Desnoyers: > > > Thoughts ? > > > > /* Unregister rseq TLS from kernel. */ > > if (has_rseq && __rseq_unregister_current_thread ()) > > abort(); > > > > advise_stack_range (pd->stackblock, pd->stackblock_size, (uintptr_t) pd, > > pd->guardsize); > > > > /* If the thread is detached free the TCB. */ > > if (IS_DETACHED (pd)) > > /* Free the TCB. */ > > __free_tcb (pd); > > Considering that we proceed to free the TCB, I really hope that all > signals are blocked at this point. (I have not checked this, though.) > > Wouldn't this address your concern about access to the rseq area? I'm not familiar with glibc's logic here, but for other reasons, I don't think freeing it is safe until the kernel task exit futex (set via clone or set_tid_address) has fired. I would guess __free_tcb just sets up for it to be reclaimable when this happens rather than immediately freeing it for reuse. Rich
