* Oleg Nesterov <o...@redhat.com> [2012-07-08 22:30:03]: > uprobe_munmap() does get_user_pages() and it is also called from > the final mmput()->exit_mmap() path. This slows down exit/mmput() > for no reason, and I think it is simply dangerous/wrong to try to > fault-in a page into the dying mm. If nothing else, this happens > after the last sync_mm_rss(), afaics handle_mm_fault() can change > the task->rss_stat and make the subsequent check_mm() unhappy. > > Change uprobe_munmap() to check mm->mm_users != 0. > > Signed-off-by: Oleg Nesterov <o...@redhat.com>
Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com> > --- > kernel/events/uprobes.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index a93b6df..47c4e24 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -1082,6 +1082,9 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned > long start, unsigned lon > if (!atomic_read(&uprobe_events) || !valid_vma(vma, false)) > return; > > + if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */ > + return; > + > if (!atomic_read(&vma->vm_mm->uprobes_state.count)) > return; > > -- > 1.5.5.1 > -- 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/
