On 09/26, Peter Zijlstra wrote: > > On Mon, 2011-09-26 at 21:31 +0530, Srikar Dronamraju wrote: > > * Peter Zijlstra <peterz@xxxxxxxxxxxxx> [2011-09-26 15:59:13]: > > > > > On Tue, 2011-09-20 at 17:32 +0530, Srikar Dronamraju wrote: > > > > Hence provide some extra > > > > + * time (by way of synchronize_sched() for breakpoint hit threads to acquire > > > > + * the uprobes_treelock before the uprobe is removed from the rbtree. > > > > > > 'Some extra time' doesn't make me all warm an fuzzy inside, but instead > > > screams we fudge around a race condition. > > > > The extra time provided is sufficient to avoid the race. So will modify > > it to mean "sufficient" instead of "some". > > > > Would that suffice? > > Much better, for extra point, explain why its sufficient as well ;-) +1 ;) I can't understand why synchronize_sched helps. In fact it is very possible I simply misunderstood the problem, I'll appreciate if you can explain. Just for example. Suppose that uprobe_notify_resume() sleeps in down_read(mmap_sem). In this case synchronize_sched() can return even before it takes this sem, how this can help the subsequent find_uprobe() ? Or that task can be simply preempted before. Or I missed the point completely? Oleg. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>