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Date:   Tue, 1 Nov 2022 12:49:11 +0000
From:   'Szabolcs Nagy' <szabolcs.nagy@arm.com>
To:     David Laight <David.Laight@ACULAB.COM>
Cc:     Theodore Ts'o <tytso@mit.edu>,
        "linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
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        <linux-arm-kernel@lists.infradead.org>
Subject: Re: linux interprets an fcntl int arg as long
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The 11/01/2022 12:19, David Laight wrote:
> From: 'Szabolcs Nagy' <szabolcs.nagy@arm.com>
> > SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
> > {
> 
> That is just a wrapper and calls do_fcntl().
> which needs changing to be add:
> 	arg &= ~0U;
> before the switch(cmd) {

this makes sense.
i thought previously you meant masking in userspace.

although if you mask there then many linux internal
apis could use int instead of long arg.

do you want me to post a patch? (i'm not a kernel
developer)