From: Segher Boessenkool <segher@kernel.crashing.org>
To: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: open list <linux-kernel@vger.kernel.org>,
lkft-triage@lists.linaro.org,
Linux Regressions <regressions@lists.linux.dev>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
Anders Roxell <anders.roxell@linaro.org>,
Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>,
clang-built-linux <llvm@lists.linux.dev>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <nathan@kernel.org>,
Jeff Xu <jeffxu@chromium.org>,
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
Dan Carpenter <dan.carpenter@linaro.org>
Subject: Re: powerpc: io-defs.h:43:1: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
Date: Tue, 16 Apr 2024 05:38:19 -0500 [thread overview]
Message-ID: <20240416103819.GQ19790@gate.crashing.org> (raw)
In-Reply-To: <CA+G9fYtEh8zmq8k8wE-8RZwW-Qr927RLTn+KqGnq1F=ptaaNsA@mail.gmail.com>
On Tue, Apr 16, 2024 at 03:02:52PM +0530, Naresh Kamboju wrote:
> In file included from arch/powerpc/include/asm/io.h:672:
> arch/powerpc/include/asm/io-defs.h:43:1: error: performing pointer
> arithmetic on a null pointer has undefined behavior
> [-Werror,-Wnull-pointer-arithmetic]
It is not UB, but just undefined: the program is meaningless.
It is not a null pointer but even a null pointer constant here. It
matters in places, including here.
It would help if the warnings were more correct :-(
Segher
WARNING: multiple messages have this Message-ID (diff)
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
Anders Roxell <anders.roxell@linaro.org>,
Linux Regressions <regressions@lists.linux.dev>,
Arnd Bergmann <arnd@arndb.de>,
clang-built-linux <llvm@lists.linux.dev>,
Nick Desaulniers <ndesaulniers@google.com>,
open list <linux-kernel@vger.kernel.org>,
lkft-triage@lists.linaro.org,
"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
Jeff Xu <jeffxu@chromium.org>,
"Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Dan Carpenter <dan.carpenter@linaro.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: powerpc: io-defs.h:43:1: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
Date: Tue, 16 Apr 2024 05:38:19 -0500 [thread overview]
Message-ID: <20240416103819.GQ19790@gate.crashing.org> (raw)
In-Reply-To: <CA+G9fYtEh8zmq8k8wE-8RZwW-Qr927RLTn+KqGnq1F=ptaaNsA@mail.gmail.com>
On Tue, Apr 16, 2024 at 03:02:52PM +0530, Naresh Kamboju wrote:
> In file included from arch/powerpc/include/asm/io.h:672:
> arch/powerpc/include/asm/io-defs.h:43:1: error: performing pointer
> arithmetic on a null pointer has undefined behavior
> [-Werror,-Wnull-pointer-arithmetic]
It is not UB, but just undefined: the program is meaningless.
It is not a null pointer but even a null pointer constant here. It
matters in places, including here.
It would help if the warnings were more correct :-(
Segher
next prev parent reply other threads:[~2024-04-16 11:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-16 9:32 powerpc: io-defs.h:43:1: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] Naresh Kamboju
2024-04-16 9:32 ` Naresh Kamboju
2024-04-16 10:38 ` Segher Boessenkool [this message]
2024-04-16 10:38 ` Segher Boessenkool
2024-04-16 11:09 ` David Laight
2024-04-16 11:09 ` David Laight
2024-04-16 11:01 ` Arnd Bergmann
2024-04-16 11:01 ` Arnd Bergmann
2024-04-16 11:55 ` Arnd Bergmann
2024-04-16 11:55 ` Arnd Bergmann
2024-04-16 12:42 ` Dan Carpenter
2024-04-16 12:42 ` Dan Carpenter
2024-04-16 12:44 ` Arnd Bergmann
2024-04-16 12:44 ` Arnd Bergmann
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