From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Petr Mladek <pmladek@suse.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: [RFC][PATCH] printf: Harden accessing pointer dereference in vsprintf()
Date: Mon, 6 Jan 2025 21:29:28 -0500 [thread overview]
Message-ID: <20250106212928.7b836da9@gandalf.local.home> (raw)
In-Reply-To: <CAHk-=whe3Kzk06s7dW4xwN+oiO2sDyDHCGOGrY892VtCLUQ1ig@mail.gmail.com>
On Mon, 6 Jan 2025 15:29:01 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Mon, 6 Jan 2025 at 14:25, Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Linus had suggested adding this kind of check[1]. This is a bit different
> > than Linus's solution as it utilizes copy_from_kernel_nofault() and doesn't
> > require calls to pagefault_disable() and extra labels.
>
> Yeah, and it generates horrendous code as a result.
>
I guess the question is do we prefer horrendous code generated or what we see?
vsprintf() is used in critical paths, but I wonder how much these two
versions actually make a difference in performance? If they do, then yeah,
the open coded version would be better.
-- Steve
next prev parent reply other threads:[~2025-01-07 2:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-06 22:27 Steven Rostedt
2025-01-06 23:29 ` Linus Torvalds
2025-01-07 2:29 ` Steven Rostedt [this message]
2025-01-07 3:05 ` Linus Torvalds
2025-01-07 0:33 ` Kees Cook
2025-01-07 4:33 ` Sergey Senozhatsky
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