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From: David Laight <David.Laight@ACULAB.COM>
To: 'Christophe JAILLET' <christophe.jaillet@wanadoo.fr>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"acme@kernel.org" <acme@kernel.org>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"alexander.shishkin@linux.intel.com" 
	<alexander.shishkin@linux.intel.com>,
	"jolsa@redhat.com" <jolsa@redhat.com>,
	"namhyung@kernel.org" <namhyung@kernel.org>,
	"kan.liang@linux.intel.com" <kan.liang@linux.intel.com>,
	"zhe.he@windriver.com" <zhe.he@windriver.com>,
	"dzickus@redhat.com" <dzickus@redhat.com>,
	"jstancek@redhat.com" <jstancek@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"kernel-janitors@vger.kernel.org"
	<kernel-janitors@vger.kernel.org>
Subject: RE: [PATCH] perf cpumap: Use scnprintf instead of snprintf
Date: Mon, 23 Mar 2020 15:11:40 +0000	[thread overview]
Message-ID: <c0441e54a07e424f9646ca232d44e9d8@AcuMS.aculab.com> (raw)
In-Reply-To: <20200322172523.2677-1-christophe.jaillet@wanadoo.fr>

From: Christophe JAILLET
> Sent: 22 March 2020 17:25
> 'scnprintf' returns the number of characters written in the output buffer
> excluding the trailing '\0', instead of the number of characters which
> would be generated for the given input.
> 
> Both function return a number of characters, excluding the trailing '\0'.
> So comparaison to check if it overflows, should be done against max_size-1.
> Comparaison against max_size can never match.

NACK.
Since snprintf() returns the number of characters it would have
written to an infinite buffer the comparison can 'match'.

However it should test for (ret >= PATH_MAX).

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


  parent reply	other threads:[~2020-03-23 15:11 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-22 17:25 [PATCH] perf cpumap: Use scnprintf instead of snprintf Christophe JAILLET
2020-03-23 11:03 ` Dan Carpenter
2020-03-23 12:08   ` Christophe JAILLET
2020-03-23 12:08     ` Christophe JAILLET
2020-03-23 12:16     ` Dan Carpenter
2020-03-23 15:11 ` David Laight [this message]
2020-03-23 15:20   ` Christophe JAILLET
2020-03-23 15:20     ` Christophe JAILLET

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