From: David Laight <David.Laight@ACULAB.COM>
To: 'Segher Boessenkool' <segher@kernel.crashing.org>,
Arnd Bergmann <arnd@kernel.org>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"Arnd Bergmann" <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"llvm@lists.linux.dev" <llvm@lists.linux.dev>,
Nick Desaulniers <ndesaulniers@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
"Bill Wendling" <morbo@google.com>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
Justin Stitt <justinstitt@google.com>,
"Jiri Slaby" <jirislaby@kernel.org>
Subject: RE: [PATCH] tty: hvc-iucv: fix function pointer casts
Date: Wed, 14 Feb 2024 09:46:33 +0000 [thread overview]
Message-ID: <57d72e2ccc8245fe99982613a11c461c@AcuMS.aculab.com> (raw)
In-Reply-To: <20240213191254.GA19790@gate.crashing.org>
From: Segher Boessenkool
> Sent: 13 February 2024 19:13
>
> On Tue, Feb 13, 2024 at 11:17:49AM +0100, Arnd Bergmann wrote:
> > clang warns about explicitly casting between incompatible function
> > pointers:
> >
> > drivers/tty/hvc/hvc_iucv.c:1100:23: error: cast from 'void (*)(const void *)' to 'void (*)(struct
> device *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
> > 1100 | priv->dev->release = (void (*)(struct device *)) kfree;
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Such a cast of course is explicitly allowed by 6.3.2.3/8, only calling a
> function using a non-compatible type is UB. This warning message is
> quite misleading. Doubly so because of the -Werror, as always.
But it will get called using the wrong type.
And (is it) fine-ibt will reject the incorrect call.
Has clang/gcc added an attribute to 'seed' the ibt hash yet?
So that functions that are void (*)(void) can be separated?
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2024-02-14 9:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-13 10:17 [PATCH] tty: hvc-iucv: fix function pointer casts Arnd Bergmann
2024-02-13 19:12 ` Segher Boessenkool
2024-02-14 9:46 ` David Laight [this message]
2024-02-14 10:37 ` Greg Kroah-Hartman
2024-02-14 12:36 ` Segher Boessenkool
2024-02-14 6:25 ` Jiri Slaby
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