Re: [PATCH] uprobes: Skip breakpoint installation on non executable vmas

On Thu, Aug 6, 2026 at 8:35 AM Oleg Nesterov <[email protected]> wrote:
>
> On 08/06, Sumanth Korikkar wrote:
> >
> > On Thu, Aug 06, 2026 at 01:01:11PM +0200, Oleg Nesterov wrote:
> > >
> > > But your change in install_breakpoint() essentually reverts that commit?
> > > If uprobe_register() -> register_for_each_vma() finds a VM_MAYEXEC vma
> > > without VM_EXEC valid_vma() will return true, but then install_breakpoint()
> > > will fail anyway.
> >
> > Initially non exec vma will be ignored via uprobe_register(),
> > install_breakpoint() will reject non vma mappings initially.
> >
> > As far as I understand,  if mprotect(PROT_EXEC) is performed later by a
> > process, it adds VM_EXEC flag to vma and calls vma_complete() via
> > vma_modify_flags(). uprobe_mmap() will then call install_breakpoint()
> > and now it should succeed because VM_EXEC is set.
>
> Heh, I am stupid the 2nd time in the same thread ;)
>
> Sumanth, thanks for correcting me! It seems that I forgot everything about
> these code paths.
>
> Then this change makes more sense, but the VM_EXEC check needs the comment
> to explain this all.
>
> However, I personally still don't think it's worth "fixing". But I leave the
> decision to Andrii and Jiri who (unlike me) understand how USDT's are used.
>

I agree, I don't see what needs to be fixed here.

> Oleg.
>