search for: tif_sigpend

...> also exit since it's the same thread group and it does: > > do_exit -> exit_files -> put_files_struct -> close_files -> fput Ah. thanks. I confused CLONE_FS in vhost_task_create() with CLONE_FILES. > > Also. Suppose that vhost_worker() dequeues SIGKILL and clears TIF_SIGPENDING. > > > > SIGSTOP, PTRACE_INTERRUPT, freezer can come and set TIF_SIGPENDING again. > > In this case the main for (;;) loop will spin without sleeping until > > vhost_task_should_stop() becomes true? > > I see. So I either have to be able to call get_signal after SIG...

When get_pending detects the task has been marked to be killed we try to clean up the SIGKLL by doing a sigdelset and recalc_sigpending, but we still leave it in shared_pending. If the signal is being short circuit delivered there is no need to put in shared_pending so this adds a check in complete_signal. This patch was modified from Eric Biederman <ebiederm at xmission.com> original

...t will stop new IOs from being queued * and check for outstanding cmd responses. It will then * call vhost_task_stop to tell us to return and exit. */ if (signal_pending(current)) { struct ksignal ksig; if (!killed) killed = get_signal(&ksig); clear_thread_flag(TIF_SIGPENDING); } continue; } ------------------------------------------------------------------------------- But let me ask a couple of questions. Let's forget this patch, let's look at the current code: node = llist_del_all(&worker->work_list); if (!node) schedule(); node...

...remember > + * what was set. > + * > + * This thread won't actually exit until all > + * of the file descriptors are closed, and > + * the release function is called. > + */ > + dead = get_signal(&ksig); > + if (dead) > + clear_thread_flag(TIF_SIGPENDING); this can't be right or I am totally confused. Another signal_wake_up() can come right after clear(SIGPENDING). Again, I'll try to re-read this patch, but let me ask anyway... Do we have a plan B? I mean... iirc you have mentioned that you can change these code paths to do somethin...

...utstanding cmd responses. It will then > + * call vhost_task_stop to tell us to return and exit. > + */ > + if (!dead && signal_pending(current)) { > + struct ksignal ksig; > + > + dead = get_signal(&ksig); > + if (dead) > + clear_thread_flag(TIF_SIGPENDING); Does get_signal actually return true only on SIGKILL then? > + } > + } > > node = llist_reverse_order(node); > /* make sure flag is seen after deletion */ > diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h > index 537cbf9a2ade..249a5ece9de...

...and check for outstanding cmd responses. It will then > * call vhost_task_stop to tell us to return and exit. > */ > if (signal_pending(current)) { > struct ksignal ksig; > > if (!killed) > killed = get_signal(&ksig); > > clear_thread_flag(TIF_SIGPENDING); > } > > continue; > } I want to point out that we need to consider not just SIGKILL, but SIGABRT that causes a coredump, as well as the process peforming an ordinary exit(2). All of which will cause get_signal to return SIGKILL in this context. > > ----------------...

...P, + * or clear fatal_signal_pending, but remember + * what was set. + * + * This thread won't actually exit until all + * of the file descriptors are closed, and + * the release function is called. + */ + dead = get_signal(&ksig); + if (dead) + clear_thread_flag(TIF_SIGPENDING); + } + + did_work = vtsk->fn(vtsk->data); + if (!did_work) { + set_current_state(TASK_INTERRUPTIBLE); + schedule(); + } + } - ret = vtsk->fn(vtsk->data); complete(&vtsk->exited); - do_exit(ret); + do_exit(0); +} + +/** + * vhost_task_wake - wakeup the vhost_task +...

The following patches made over Linus's tree fix the 2 bugs: 1. vhost worker task shows up as a process forked from the parent that did VHOST_SET_OWNER ioctl instead of a process under root/kthreadd. This was causing breaking scripts. 2. vhost_tasks didn't disable or add support for freeze requests. The following patches fix these issues by making the vhost_task task a thread under the