On 04/10, Steven Rostedt wrote: > > On Thu, 10 Apr 2014 21:38:20 +0200 > Oleg Nesterov <o...@redhat.com> wrote: > > > I _think_ that the kernel thread can only return from "call *%rbx" if > > it is no longer a kernel thread, iow, do_execve() was called. > > Ah right. But only in special cases. > > Actually, it only returns if the function in kernel_thread() returns, > and in the case of ____call_usermodehelper, it does an exec and > returns on success. But if it fails, it needs to call do_exit().
Yes. If it simply returns the kernel will crash, without start_thread/etc "int_ret_from_sys_call" can do nothing good. So we can conclude that "there is only one case when a kernel thread can reach the usual syscall exit tracing path:" from cc3b13c11c567c69 is no longer valid and we can kille the PF_KTHREAD check in regfuncs. > Thus, it's not sufficient to just say "only if do_execve is called" but > to say, if the handler that is called is only allowed to return iff it > did a execve first and succeeded. I do remember, I already told you are pedant! Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
