Re: [PATCH] mm/madvise: preserve uprobe breakpoints across MADV_DONTNEED

Daniel Walker (danielwa)
2026-04-29T21:12:34Z

On Wed, Apr 29, 2026 at 05:24:25PM +0200, Oleg Nesterov wrote:
> On 04/29, David Hildenbrand (Arm) wrote:
> >
> > On 4/29/26 15:15, Darko Tominac wrote:
> >
> > > uprobe infrastructure does not re-instrument pages on individual page
> > > faults (uprobe_mmap() is only called during VMA creation, not on
> > > page-in), the breakpoints are silently lost once the discarded pages are
> > > re-read from the backing file. The probes stop firing with no error
> > > indication, and the only recovery is to unregister and re-register the
> > > affected uprobes.
> >
> > Right. Don't MADV_DONTNEED uprobes, just like you are not supposed to
> > MADV_DONTNEED debugger breakpoints/set data etc. :)
>
> Agreed, thanks.

Shouldn't there be some sort of compensation or notification for this, or is each person that
hits this suppose to just scratch their head and send a patch that's rejected?

Daniel