On Tue, 24 Apr 2007 04:30:22 -0600 [EMAIL PROTECTED] (Eric W. Biederman) wrote:
> Andrew Morton <[EMAIL PROTECTED]> writes: > > > On Fri, 13 Apr 2007 21:13:13 -0600 [EMAIL PROTECTED] (Eric W. Biederman) > > wrote: > > > >> This patch reworks kthread_stop so it is more flexible and it causes > >> the target kthread to abort interruptible sleeps. Allowing a larger > >> class of kernel threads to use to the kthread API. > >> > >> The changes start by defining TIF_KTHREAD_STOP on all architectures. > >> TIF_KTHREAD_STOP is a per process flag that I can set from another > >> process to indicate that a kernel thread should stop. > >> > >> wake_up_process in kthread_stop has been replaced by signal_wake_up > >> ensuring that the kernel thread if sleeping is woken up in a timely > >> manner and with TIF_SIGNAL_PENDING set, which causes us to break out > >> of interruptible sleeps. > >> > >> recalc_signal_pending was modified to keep TIF_SIGNAL_PENDING set for > >> as long as TIF_KTHREAD_STOP is set. > >> > >> Arbitrary paths to do_exit are now allowed. I have placed a > >> completion on the thread stack and pointed vfork_done at it, when the > >> mm_release is called from do_exit the completion will be called. > >> Since the completion is stored on the stack it is important that > >> kthread() now calls do_exit ensuring the stack frame that holds the > >> completion is never released, and so that our exit_code is certain to > >> make it unchanged all the way to do_exit. > >> > >> To allow kthread_stop to read the process exit code when exit_mm wakes > >> it up I have moved the setting of exit_code to the beginning of > >> do_exit. > > > > This patch causes this oops: http://userweb.kernel.org/~akpm/s5000508.jpg > > with this config: http://userweb.kernel.org/~akpm/config-x.txt > > Thanks. If I am reading the oops properly this happened during bootup and > vfork_done was set to NULL? Yes, it was fairly early in boot. I didn't check what we're oopsing on. > The NULL vfork_done is really weird as exec is the only thing that sets > vfork_done to NULL. > > Either I've got a stupid bug in there somewhere or we have just found > the weirdest memory stomp. I will take a look and see if I can reproduce > this shortly. That was on a Fedora Core 3 machine. One of those older distros I keep around to trip people up. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
