On Wed, Apr 29, 2026 at 11:11 PM Daniel Walker (danielwa) <[email protected]> wrote: > 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?
I guess we could add a pr_warn_once() that warns when madvise(MADV_DONTNEED) is called on a read+execute file mapping, and/or (as David said) add an explicit note in the madvise() manpage about how that can interfere with software breakpoints and uprobes?
