Re: [PATCH 15/18] uprobes: wait for mmap_sem for write killable

[Michal Hocko]

On Mon 29-02-16 16:57:13, Oleg Nesterov wrote:
> On 02/29, Michal Hocko wrote:
> >
> > --- a/kernel/events/uprobes.c
> > +++ b/kernel/events/uprobes.c
> > @@ -1130,7 +1130,9 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area)
> >  	struct vm_area_struct *vma;
> >  	int ret;
> >
> > -	down_write(&mm->mmap_sem);
> > +	if (down_write_killable(&mm->mmap_sem))
> > +		return -EINTR;
> > +
> 
> Yes, but then dup_xol_work() should probably check fatal_signal_pending() to
> suppress uprobe_warn(), the warning looks like a kernel problem.

Ahh, I see. I didn't understand what is the purpose of the warning. Does
the following work for you?
---
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index a79315d0f711..fb4a6bcc88ce 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1470,7 +1470,8 @@ static void dup_xol_work(struct callback_head *work)
 	if (current->flags & PF_EXITING)
 		return;
 
-	if (!__create_xol_area(current->utask->dup_xol_addr))
+	if (!__create_xol_area(current->utask->dup_xol_addr) &&
+			!fatal_signal_pending(current)
 		uprobe_warn(current, "dup xol area");
 }
 
-- 
Michal Hocko
SUSE Labs