From: Matthew Wilcox <willy@infradead.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Jagdish Gediya <jvgediya@linux.ibm.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
ying.huang@intel.com, dave.hansen@intel.com,
Jonathan.Cameron@huawei.com, adobriyan@gmail.com,
akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
rf@opensource.cirrus.com, pmladek@suse.com, will@kernel.org
Subject: Re: [PATCH v3 1/2] lib/kstrtox.c: Add "false"/"true" support to kstrtobool()
Date: Mon, 25 Jul 2022 16:21:11 +0100 [thread overview]
Message-ID: <Yt605xj898VSAsA3@casper.infradead.org> (raw)
In-Reply-To: <Yt6u34sigPEkeZ0Y@FVFF77S0Q05N.cambridge.arm.com>
On Mon, Jul 25, 2022 at 03:55:27PM +0100, Mark Rutland wrote:
> On Tue, Apr 26, 2022 at 11:32:02PM +0530, Jagdish Gediya wrote:
> > At many places in kernel, It is necessary to convert sysfs input
> > to corrosponding bool value e.g. "false" or "0" need to be converted
> > to bool false, "true" or "1" need to be converted to bool true,
> > places where such conversion is needed currently check the input
> > string manually, kstrtobool() can be utilized at such places but
> > currently it doesn't have support to accept "false"/"true".
> >
> > Add support to accept "false"/"true" as valid string in kstrtobool().
> >
> > Signed-off-by: Jagdish Gediya <jvgediya@linux.ibm.com>
> > Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>
> I've just spotted that this broke arm64's "rodata=full" command line option,
That isn't a documented option.
rodata= [KNL]
on Mark read-only kernel memory as read-only (default).
off Leave read-only kernel memory writable for debugging.
Hopefully this is an object lesson in why you need to update the
documentation when you extend a feature.
> since "full" gets parsed as 'f' = FALSE, when previously that would have been
> rejected. So anyone passing "rodata=full" on the command line will have rodata
> disabled, which is not what they wanted.
>
> The current state of things is a bit messy (we prase the option twice because
> arch code needs it early), and we can probably fix that with some refactoring,
> but I do wonder if we actually want to open up the sysfs parsing to accept
> anything *beginning* with [tTfF] rather than the full "true" and "false"
> strings as previously, or whether it's worth reverting this for now in case
> anything else is affected.
Well, that's going to break people who've started using the new option.
As a quick fix, how about only allowing either "f\0" or "fa"?
next prev parent reply other threads:[~2022-07-25 15:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-26 18:02 [PATCH v3 1/2] lib/kstrtox.c: Add "false"/"true" support to kstrtobool() Jagdish Gediya
2022-04-26 18:02 ` [PATCH v3 2/2] mm: Convert sysfs input to bool using kstrtobool() Jagdish Gediya
2022-04-26 19:14 ` [PATCH v3 1/2] lib/kstrtox.c: Add "false"/"true" support to kstrtobool() Matthew Wilcox
2022-04-26 20:40 ` David Laight
2022-04-27 10:21 ` Jagdish Gediya
2022-04-27 15:13 ` Andy Shevchenko
2022-04-27 17:39 ` Andrew Morton
2022-04-27 18:17 ` Andy Shevchenko
2022-04-27 18:19 ` Andy Shevchenko
2022-07-25 14:55 ` Mark Rutland
2022-07-25 15:21 ` Matthew Wilcox [this message]
2022-07-25 15:36 ` Mark Rutland
2022-07-29 14:35 ` Andy Shevchenko
2022-07-29 14:36 ` Andy Shevchenko
2022-08-25 13:39 ` Petr Mladek
2022-08-26 10:35 ` Will Deacon
2022-07-29 15:17 ` Alexey Dobriyan
2022-07-29 15:32 ` Andy Shevchenko
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