Re: [PATCH] vsprintf: Do not break early boot with probing addresses

Hi Steve,

On Tue, May 14, 2019 at 9:35 PM Steven Rostedt [off-list ref] wrote:

On Tue, 14 May 2019 21:13:06 +0200
Geert Uytterhoeven [off-list ref] wrote:

quoted

quoted

quoted

Do we care about the value? "(-E%u)"?

That too could be confusing. What would (-E22) be considered by a user
doing an sprintf() on some string. I know that would confuse me, or I
would think that it was what the %pX displayed, and wonder why it
displayed it that way. Whereas "(fault)" is quite obvious for any %p
use case.

I would immediately understand there's a missing IS_ERR() check in a
function that can return  -EINVAL, without having to add a new printk()
to find out what kind of bogus value has been received, and without
having to reboot, and trying to reproduce...

I have to ask. Has there actually been a case that you used a %pX and
it faulted, and you had to go back to find what the value of the
failure was?

If it faulted, the bad pointer value is obvious from the backtrace.
If the code avoids the fault by verifying the pointer and returning
"(efault)" instead, the bad pointer value is lost.

Or am I missing something?

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds