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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Tobin C . Harding" <me@tobin.cc>, Joe Perches <joe@perches.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.cz>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 7/9] vsprintf: Consolidate handling of unknown pointer specifiers
Date: Fri, 8 Feb 2019 19:25:18 +0200	[thread overview]
Message-ID: <20190208172518.GV9224@smile.fi.intel.com> (raw)
In-Reply-To: <20190208152310.29531-8-pmladek@suse.com>

On Fri, Feb 08, 2019 at 04:23:08PM +0100, Petr Mladek wrote:
> There are few printk formats that make sense only with two or more
> specifiers. Also some specifiers make sense only when a kernel feature
> is enabled.
> 
> The handling of unknown specifiers is inconsistent and not helpful.
> Using WARN() looks like an overkill for this type of error. pr_warn()
> is not good either. It would by handled via printk_safe buffer and
> it might be hard to match it with the problematic string.
> 
> A reasonable compromise seems to be writing the unknown format specifier
> into the original string with a question mark, for example (%pC?).
> It should be self-explaining enough. Note that it is in brackets
> to follow the (null) style.
> 

> Note that the changes in test_printf.c revert many changes made
> by the commit 4d42c44727a062e233 ("lib/vsprintf: Print time and
> date in human readable format via %pt\n"). The format %pt does
> not longer produce a hashed pointer.

It seems in further patch you partially restore back what was brought by that patch.
I would suggest not to touch at least changes for plain_pointer_to_buffer().

Also it would be nice to have a coverage for hashed pointers.

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2019-02-08 17:25 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-08 15:23 [PATCH v6 0/9] vsprintf: Prevent silent crashes and consolidate error handling Petr Mladek
2019-02-08 15:23 ` [PATCH v6 1/9] vsprintf: Shuffle restricted_pointer() Petr Mladek
2019-02-08 15:23 ` [PATCH v6 2/9] vsprintf: Consistent %pK handling for kptr_restrict == 0 Petr Mladek
2019-02-08 15:23 ` [PATCH v6 3/9] vsprintf: Do not check address of well-known strings Petr Mladek
2019-02-08 17:27   ` Andy Shevchenko
2019-02-08 15:23 ` [PATCH v6 4/9] vsprintf: Factor out %p[iI] handler as ip_addr_string() Petr Mladek
2019-02-08 15:23 ` [PATCH v6 5/9] vsprintf: Factor out %pV handler as va_format() Petr Mladek
2019-02-08 17:11   ` Joe Perches
2019-02-12 13:00     ` Petr Mladek
2019-02-12 14:32       ` Steven Rostedt
2019-02-12 17:58       ` Joe Perches
2019-02-12 19:47         ` Steven Rostedt
2019-02-12 20:22         ` Rasmus Villemoes
2019-02-08 15:23 ` [PATCH v6 6/9] vsprintf: Factor out %pO handler as kobject_string() Petr Mladek
2019-02-08 15:23 ` [PATCH v6 7/9] vsprintf: Consolidate handling of unknown pointer specifiers Petr Mladek
2019-02-08 17:25   ` Andy Shevchenko [this message]
2019-02-12 13:35     ` Petr Mladek
2019-02-08 15:23 ` [PATCH v6 8/9] vsprintf: Prevent crash when dereferencing invalid pointers Petr Mladek
2019-02-19  3:30   ` Sergey Senozhatsky
2019-02-19 11:02     ` Andy Shevchenko
2019-02-19 12:51       ` Sergey Senozhatsky
2019-02-19 13:49         ` Andy Shevchenko
2019-02-19 14:15           ` Sergey Senozhatsky
2019-02-20 10:24             ` Petr Mladek
2019-02-08 15:23 ` [PATCH v6 9/9] vsprintf: Avoid confusion between invalid address and value Petr Mladek
2019-02-08 17:27   ` Andy Shevchenko
2019-02-12 15:45     ` Petr Mladek
2019-02-13 13:54       ` Andy Shevchenko
2019-02-14  8:42         ` Petr Mladek
2019-02-14 12:45           ` Andy Shevchenko
2019-02-19  3:03   ` Sergey Senozhatsky
2019-02-19 11:06     ` Andy Shevchenko
2019-02-20  9:24       ` Petr Mladek
2019-02-21  1:47         ` Sergey Senozhatsky

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