From: Helge Deller <deller@gmx.de>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 00/14] Fix wrong %pF and %pS printk format specifier usages
Date: Thu, 7 Sep 2017 08:01:08 +0200 [thread overview]
Message-ID: <8b93f9ca-95f6-4e40-1cc8-d1a65833abff@gmx.de> (raw)
In-Reply-To: <20170907004522.GA3885@jagdpanzerIV.localdomain>
On 07.09.2017 02:45, Sergey Senozhatsky wrote:
> On (09/06/17 22:27), Helge Deller wrote:
>> This patch series fixes the wrong usages of the %pF and %pS printk format
>> specifiers throughout the kernel code.
>>
>> Both specifiers have the same result on most architectures. But on ia64, ppc64
>> and parisc64 architectures the %pF specifier does an extra conversion because
>> there function pointers are actually function descriptors.
>
> hm...
> can we fix it in lib/vsprintf.c instead?
There is nothing to fix in vsprintf, because it is already providing
both %pF and %pS for the two different architecture-specific API call
implementations.
> a) the patch set has "there is no problem on platform A, but still
> let's just change it"
>
> which is probably fine. but
>
> b) you tweak/fix the currently existing users, OK. but there, most
> likely, will be new users that will require fixes in the future.
Please read the documentation in Documentation/printk-formats.txt.
It's really as simple that if you use function pointers you *need to*
use %pF, and if you use raw addresses of functions, you *need to* use
%pS. If you use the correct specifier the output will automatically
be correct for all architectures. If you don't, then the output on
ia64, ppc64 and parisc64 architectures will be wrong and may lead
to kernel crashes in the worst case.
My patch series simply fixes that code which has it wrong.
It has no impact at all on users on x86, ARM, mips and
other platforms.
Helge
next prev parent reply other threads:[~2017-09-07 6:05 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-06 20:27 [PATCH 00/14] Fix wrong %pF and %pS printk format specifier usages Helge Deller
2017-09-06 20:27 ` [PATCH 01/14] arm: Use %pS printk format for symbols from direct addresses Helge Deller
2017-09-06 20:27 ` [PATCH 02/14] um: " Helge Deller
2017-09-12 12:10 ` Petr Mladek
2017-09-21 20:13 ` Richard Weinberger
2017-09-06 20:27 ` [PATCH 03/14] x86: " Helge Deller
2017-09-06 20:27 ` [PATCH 04/14] ti_sci: Use %pS printk format for " Helge Deller
2017-09-08 23:30 ` Nishanth Menon
2017-09-09 0:30 ` Santosh Shilimkar
2017-09-06 20:27 ` [PATCH 05/14] i915: " Helge Deller
2017-09-27 12:24 ` [Intel-gfx] " Daniel Vetter
2017-09-06 20:27 ` [PATCH 06/14] md/bcache: " Helge Deller
2017-09-07 4:50 ` Coly Li
2017-09-07 7:42 ` Helge Deller
2017-09-07 7:49 ` Coly Li
2017-09-07 8:05 ` Sergey Senozhatsky
2017-09-06 20:27 ` [PATCH 07/14] power/avs: " Helge Deller
2017-09-08 23:37 ` Nishanth Menon
2017-09-06 20:27 ` [PATCH 08/14] fs/f2fs: " Helge Deller
2017-09-06 20:27 ` [PATCH 09/14] fs/pstore: " Helge Deller
2018-11-29 23:26 ` Kees Cook
2018-11-29 23:49 ` Luck, Tony
2018-11-30 0:40 ` Kees Cook
2017-09-06 20:27 ` [PATCH 10/14] fs/xfs: " Helge Deller
2017-09-08 7:38 ` Christoph Hellwig
2017-09-18 18:37 ` Darrick J. Wong
2017-09-06 20:27 ` [PATCH 11/14] smp: Use %pF printk format specifier for function pointers Helge Deller
2017-09-06 20:27 ` [PATCH 12/14] mm/memblock: Use %pS printk format for direct addresses Helge Deller
2017-09-06 20:28 ` [PATCH 13/14] netfilter/ipvs: " Helge Deller
2017-10-09 5:52 ` Simon Horman
2017-11-06 13:46 ` Pablo Neira Ayuso
2017-09-06 20:28 ` [PATCH 14/14] sound/core: " Helge Deller
2017-09-07 8:36 ` Takashi Iwai
2017-09-07 0:45 ` [PATCH 00/14] Fix wrong %pF and %pS printk format specifier usages Sergey Senozhatsky
2017-09-07 6:01 ` Helge Deller [this message]
2017-09-07 7:56 ` Sergey Senozhatsky
2017-09-07 8:32 ` Sergey Senozhatsky
2017-09-07 9:12 ` Helge Deller
2017-09-07 9:36 ` Sergey Senozhatsky
2017-09-07 9:51 ` Sergey Senozhatsky
2017-09-07 12:38 ` Helge Deller
2017-09-07 16:05 ` Luck, Tony
2017-09-08 6:18 ` Sergey Senozhatsky
2017-09-08 17:25 ` Luck, Tony
2017-09-08 18:28 ` Helge Deller
2017-09-14 7:40 ` Sergey Senozhatsky
2017-09-14 8:03 ` Sergey Senozhatsky
2017-09-14 8:39 ` Helge Deller
2017-09-14 9:27 ` Sergey Senozhatsky
2017-09-14 9:47 ` Helge Deller
2017-09-14 16:01 ` Luck, Tony
2017-09-18 7:03 ` Sergey Senozhatsky
2017-09-14 6:53 ` Sergey Senozhatsky
2017-09-08 20:49 ` Helge Deller
2017-09-12 11:18 ` Petr Mladek
2017-09-14 6:44 ` Sergey Senozhatsky
2017-09-08 22:23 ` Yu, Fenghua
2017-09-14 6:35 ` Sergey Senozhatsky
2017-09-07 16:50 ` Joe Perches
2017-09-08 6:23 ` Sergey Senozhatsky
2017-09-08 20:39 ` Helge Deller
2017-09-12 12:23 ` Petr Mladek
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