From: Matthew Wilcox <willy@infradead.org>
To: David Laight <David.Laight@aculab.com>
Cc: 'Kent Overstreet' <kent.overstreet@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@vger.kernel.org" <linux-mm@vger.kernel.org>,
"pmladek@suse.com" <pmladek@suse.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"senozhatsky@chromium.org" <senozhatsky@chromium.org>,
"andriy.shevchenko@linux.intel.com"
<andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH v2 03/28] vsprintf: %pf(%p)
Date: Fri, 20 May 2022 14:08:45 +0100 [thread overview]
Message-ID: <YoeS3R4HE1fRkonT@casper.infradead.org> (raw)
In-Reply-To: <786516a0b71a4c6689592b89b146edec@AcuMS.aculab.com>
On Fri, May 20, 2022 at 08:03:29AM +0000, David Laight wrote:
> From: Matthew Wilcox
> > Sent: 19 May 2022 22:15
> >
> > On Thu, May 19, 2022 at 09:06:24PM +0000, David Laight wrote:
> > > I suspect this a very good way to blow the kernel stack.
> > > The highest stack use is already very likely to be inside
> > > the printf code in an error path somewhere.
> >
> > ...
> >
> > > Double copying using a temporary buffer isn't the end of the world.
> >
> > How can you hold both of these positions simultaneously?
>
> Mostly you only need a short(ish) buffer to format a single item.
> But even a full line buffer is probably less stack than a
> nested printf call.
> It certainly makes it possible for static analysis to determine
> maximum stack depth.
There are a lot of words in this response. Numbers, please.
> That made me realise that one of the problems doing static
> analysis of stack depth is indirect calls.
> The hashes that (IIRC) fine-ibt add to indirect calls
> and functions make it possible to tie these together.
> So you can determine the worst one of the called functions
> and use it for the stack depth at the call sites.
>
> David
>
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
>
next prev parent reply other threads:[~2022-05-20 13:08 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-19 17:23 [PATCH v2 00/28] Printbufs (now with more printbufs!) Kent Overstreet
2022-05-19 17:23 ` [PATCH v2 01/28] lib/printbuf: New data structure for printing strings Kent Overstreet
2022-05-19 18:21 ` Matthew Wilcox
2022-05-20 4:44 ` Kent Overstreet
2022-05-26 15:06 ` Petr Mladek
2022-05-26 15:21 ` Kent Overstreet
2022-05-26 15:36 ` Joe Perches
2022-05-27 10:29 ` Petr Mladek
2022-05-29 18:15 ` Kent Overstreet
2022-05-31 22:03 ` Kent Overstreet
2022-05-19 17:23 ` [PATCH v2 02/28] vsprintf: Convert to printbuf Kent Overstreet
2022-05-19 17:23 ` [PATCH v2 03/28] vsprintf: %pf(%p) Kent Overstreet
2022-05-19 18:33 ` Matthew Wilcox
2022-05-20 4:43 ` Kent Overstreet
2022-05-19 21:06 ` David Laight
2022-05-19 21:15 ` Matthew Wilcox
2022-05-20 8:03 ` David Laight
2022-05-20 13:08 ` Matthew Wilcox [this message]
2022-05-20 4:49 ` Kent Overstreet
2022-05-20 14:17 ` andriy.shevchenko
2022-05-19 21:20 ` Matthew Wilcox
2022-05-20 7:40 ` Michal Hocko
2022-05-20 15:01 ` Kent Overstreet
2022-05-20 17:56 ` Kent Overstreet
2022-05-19 17:23 ` [PATCH v2 04/28] lib/string_helpers: string_get_size() now returns characters wrote Kent Overstreet
2022-05-19 17:23 ` [PATCH v2 05/28] lib/printbuf: Heap allocation Kent Overstreet
2022-05-19 17:23 ` [PATCH v2 06/28] lib/printbuf: Tabstops, indenting Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 07/28] lib/printbuf: Unit specifiers Kent Overstreet
2022-05-19 20:21 ` Andy Shevchenko
2022-05-19 20:26 ` Kent Overstreet
2022-05-19 21:11 ` Matthew Wilcox
2022-05-20 4:40 ` Kent Overstreet
2022-05-19 21:16 ` Andy Shevchenko
2022-05-19 21:22 ` Matthew Wilcox
2022-05-20 4:36 ` Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 08/28] lib/pretty-printers: pr_string_option(), pr_bitflags() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 09/28] vsprintf: Improve number() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 10/28] vsprintf: pr_u64_minwidth(), pr_u64() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 11/28] vsprintf: Lift pr_hex_bytes() out from hex_string() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 12/28] test_printf: Drop requirement that sprintf not write past nul Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 13/28] vsprintf: Start consolidating printf_spec handling Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 14/28] vsprintf: Refactor resource_string() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 15/28] vsprintf: Refactor fourcc_string() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 16/28] vsprintf: Refactor ip_addr_string() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 17/28] vsprintf: Refactor mac_address_string() Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 18/28] vsprintf: time_and_date() no longer takes printf_spec Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 19/28] vsprintf: flags_string() " Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 20/28] vsprintf: Refactor device_node_string, fwnode_string Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 21/28] vsprintf: Refactor hex_string, bitmap_string_list, bitmap_string Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 22/28] Input/joystick/analog: Convert from seq_buf -> printbuf Kent Overstreet
2022-05-19 20:04 ` Andy Shevchenko
2022-05-19 20:19 ` Kent Overstreet
2022-05-19 21:09 ` Andy Shevchenko
2022-05-19 17:24 ` [PATCH v2 23/28] mm/memcontrol.c: Convert to printbuf Kent Overstreet
2022-05-20 7:59 ` Michal Hocko
2022-05-19 17:24 ` [PATCH v2 24/28] clk: tegra: bpmp: " Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 25/28] tools/testing/nvdimm: " Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 26/28] powerpc: " Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 27/28] x86/resctrl: " Kent Overstreet
2022-05-19 17:24 ` [PATCH v2 28/28] PCI/P2PDMA: " Kent Overstreet
2022-05-26 14:44 ` [PATCH v2 00/28] Printbufs (now with more printbufs!) Petr Mladek
2022-05-26 15:11 ` Kent Overstreet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YoeS3R4HE1fRkonT@casper.infradead.org \
--to=willy@infradead.org \
--cc=David.Laight@aculab.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=kent.overstreet@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@vger.kernel.org \
--cc=pmladek@suse.com \
--cc=rostedt@goodmis.org \
--cc=senozhatsky@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®