From: David Laight <David.Laight@ACULAB.COM>
To: 'Rasmus Villemoes' <linux@rasmusvillemoes.dk>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Miguel Ojeda <ojeda@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"rust-for-linux@vger.kernel.org" <rust-for-linux@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Gary Guo <gary@garyguo.net>, Alex Gaynor <alex.gaynor@gmail.com>,
Wedson Almeida Filho <wedsonaf@google.com>,
"Petr Mladek" <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
"Sergey Senozhatsky" <senozhatsky@chromium.org>
Subject: RE: [PATCH v4 12/20] vsprintf: add new `%pA` format specifier
Date: Mon, 14 Feb 2022 11:36:58 +0000 [thread overview]
Message-ID: <2a7dff8e0efb4142849802357284af51@AcuMS.aculab.com> (raw)
In-Reply-To: <dc9054f2-5e2b-0ae2-1022-23421668dd05@rasmusvillemoes.dk>
From: Rasmus Villemoes
> Sent: 14 February 2022 10:53
>
> On 14/02/2022 11.18, Andy Shevchenko wrote:
> > On Sat, Feb 12, 2022 at 02:03:38PM +0100, Miguel Ojeda wrote:
> >
> >> From: Gary Guo <gary@garyguo.net>
> >
> > Not sure I understand this...
> >
> >> This patch adds a format specifier `%pA` to `vsprintf` which formats
> >> a pointer as `core::fmt::Arguments`. Doing so allows us to directly
> >> format to the internal buffer of `printf`, so we do not have to use
> >> a temporary buffer on the stack to pre-assemble the message on
> >> the Rust side.
> >>
> >> This specifier is intended only to be used from Rust and not for C, so
> >> `checkpatch.pl` is intentionally unchanged to catch any misuse.
> >>
> >> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
> >> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
> >> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
> >> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
> >
> >> Signed-off-by: Gary Guo <gary@garyguo.net>
> >
> > ...together with this in the current SoB chain.
> >
> >> Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
> >> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> >
> > I'm wondering if you considered to use %pV.
> >
>
> I think the point is for vsnprintf() to call (back) into Rust code.
Doesn't that stand a reasonable chance of blowing the kernel stack?
vsnprintf() is likely to be on the 'worst case' stack path anyway.
Anything vaguely like a recursive call, or anything 'stack expensive'
inside vsnprintf() stands a real chance of overflowing the stack.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2022-02-14 11:44 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-12 13:03 [PATCH v4 00/20] Rust support Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 01/20] kallsyms: support "big" kernel symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 02/20] kallsyms: increase maximum kernel symbol length to 512 Miguel Ojeda
2022-02-22 8:19 ` Petr Mladek
2022-02-22 12:45 ` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 03/20] kallsyms: use the correct buffer size for symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 04/20] rust: add C helpers Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 05/20] rust: add `compiler_builtins` crate Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 07/20] rust: add `build_error` crate Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 08/20] rust: add `macros` crate Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 09/20] rust: add `kernel` crate's `sync` module Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 11/20] rust: export generated symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 12/20] vsprintf: add new `%pA` format specifier Miguel Ojeda
2022-02-14 10:18 ` Andy Shevchenko
2022-02-14 10:52 ` Rasmus Villemoes
2022-02-14 11:36 ` David Laight [this message]
2022-02-14 14:04 ` Miguel Ojeda
2022-02-14 12:12 ` Miguel Ojeda
2022-02-22 9:29 ` Petr Mladek
2022-02-22 10:35 ` Rasmus Villemoes
2022-02-24 9:55 ` Petr Mladek
2022-02-14 12:27 ` Miguel Ojeda
2022-02-14 13:54 ` Andy Shevchenko
2022-02-14 14:56 ` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 13/20] scripts: add `generate_rust_analyzer.py` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 14/20] scripts: decode_stacktrace: demangle Rust symbols Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 16/20] Kbuild: add Rust support Miguel Ojeda
2022-02-12 14:16 ` Russell King (Oracle)
2022-02-12 15:47 ` Miguel Ojeda
2022-02-12 16:18 ` Russell King (Oracle)
2022-02-12 18:32 ` Miguel Ojeda
2022-02-12 18:27 ` John Paul Adrian Glaubitz
2022-02-12 18:57 ` Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 17/20] samples: add Rust examples Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 18/20] MAINTAINERS: Rust Miguel Ojeda
2022-02-12 13:03 ` [PATCH v4 19/20] [RFC] drivers: gpio: PrimeCell PL061 in Rust Miguel Ojeda
2022-02-13 9:31 ` [PATCH v4 00/20] Rust support, nn/nn Geert Stappers
2022-02-13 9:55 ` Greg KH
2022-02-13 10:52 ` Geert Stappers
2022-02-14 14:16 ` Miguel Ojeda
2022-02-14 14:48 ` Geert Stappers
[not found] ` <20220212130410.6901-11-ojeda@kernel.org>
2022-02-14 5:27 ` [PATCH v4 10/20] rust: add `kernel` crate Sergey Senozhatsky
2022-02-14 13:36 ` Miguel Ojeda
2022-02-22 9:06 ` Petr Mladek
2022-02-22 12:48 ` Miguel Ojeda
2022-02-24 12:39 ` Petr Mladek
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