Re: [PATCHv2 perf/core] uprobes: Harden uretprobe syscall trampoline check

[Google]

On Tue, 11 Feb 2025 17:59:41 +0100
Oleg Nesterov <oleg@xxxxxxxxxx> wrote:

> On 02/11, Alexei Starovoitov wrote:
> >
> > > > +#define UPROBE_NO_TRAMPOLINE_VADDR ((unsigned long)-1)
> >
> > If you respin anyway maybe use ~0UL instead?
> > In the above and in
> > uprobe_get_trampoline_vaddr(),
> > since
> >
> > unsigned long trampoline_vaddr = -1;
> 
> ... or -1ul in both cases.
> 
> I agree, UPROBE_NO_TRAMPOLINE_VADDR has a single user, looks
> a bit strange...

I think both this function and uprobe_get_trampoline_vaddr()
should use the same macro as a token.
(and ~0UL is a bit more comfortable for me too :) )

----
unsigned long uprobe_get_trampoline_vaddr(void)
{
	struct xol_area *area;
	unsigned long trampoline_vaddr = -1;
----

Thank you,

> 
> Oleg.
> 
> 


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>