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

On Tue, 11 Feb 2025 17:59:41 +0100 Oleg Nesterov oleg@redhat.com 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.