From: Matthew Wilcox <willy@infradead.org>
To: Christopher Lameter <cl@linux.com>
Cc: Shyam Saini <mayhs11saini@gmail.com>,
linux-mm@kvack.org, kernel-hardening@lists.openwall.com,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH] slab: Redefine ZERO_SIZE_PTR to include ERR_PTR range
Date: Thu, 10 Oct 2019 10:44:13 -0700 [thread overview]
Message-ID: <20191010174413.GT32665@bombadil.infradead.org> (raw)
In-Reply-To: <alpine.DEB.2.21.1910101418500.27284@www.lameter.com>
On Thu, Oct 10, 2019 at 02:22:40PM +0000, Christopher Lameter wrote:
> On Thu, 10 Oct 2019, Shyam Saini wrote:
>
> > This will help error related to ERR_PTR stand out better.
>
> Maybe make ZERO_SIZE_PTR an ERRNO value instead? Then allow ERR_PTRs to be
> used instead of ZERO_SIZE_PTRs
>
> ERRNO_ZERO_OBJECT
>
> or something like that?
I was wondering about something like that too, but allocating zero bytes
isn't actually an error, and if we have code that does something like:
void *p = my_funky_alloc(size, ...);
if (IS_ERR(p))
return PTR_ERR(p);
then we might get this errno returned to userspace.
The change is definitely worth thinking about.
next prev parent reply other threads:[~2019-10-10 17:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-10 10:31 [PATCH] slab: Redefine ZERO_SIZE_PTR to include ERR_PTR range Shyam Saini
2019-10-10 14:22 ` Christopher Lameter
2019-10-10 17:44 ` Matthew Wilcox [this message]
2019-10-10 18:35 ` Christopher Lameter
2019-10-20 6:06 ` Shyam Saini
2019-10-20 15:38 ` Jann Horn
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