From: Brendan Gregg <brendan.d.gregg@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
linux-arm-kernel@vger.kernel.org,
Russell King <rmk+kernel@armlinux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
kernel-build-reports@lists.linaro.org,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH 11/13] fs: fix unsigned enum warning with gcc-4.2
Date: Tue, 3 Jan 2017 14:47:09 -0800 [thread overview]
Message-ID: <CAE40pdenVkk-JerdB905nyupoDDPiQk9qv4p1Jv62kcj3-dKhQ@mail.gmail.com> (raw)
In-Reply-To: <20161216105634.235457-12-arnd@arndb.de>
On Fri, Dec 16, 2016 at 2:56 AM, Arnd Bergmann <arnd@arndb.de> wrote:
>
> With arm-linux-gcc-4.2, almost every file we build in the kernel ends
> up with this warning:
>
> include/linux/fs.h:2648: warning: comparison of unsigned expression < 0 is always false
>
Thanks, I'd like to see this fixed as a similar warning gets printed
whenever running many of the bcc/BPF tools, which gets annoying and is
user-visible. eg:
# /usr/share/bcc/tools/xfsslower 1
In file included from /virtual/main.c:3:
/lib/modules/4.8.6-300.fc25.x86_64/build/include/linux/fs.h:2677:9:
warning: comparison of unsigned enum expression < 0 is always false
[-Wtautological-compare]
if (id < 0 || id >= READING_MAX_ID)
~~ ^ ~
1 warning generated.
Tracing XFS operations slower than 1 ms
TIME COMM PID T BYTES OFF_KB LAT(ms) FILENAME
14:44:27 cksum 4414 R 65536 0 1.02 chcon
14:44:27 cksum 4414 R 65536 0 1.20 cpio
14:44:27 cksum 4414 R 65536 0 1.01 diff
14:44:27 cksum 4414 R 65536 0 1.15 dir
[...]
This patch fixes the warning.
Brendan
>
> Later versions don't have this problem, but it's easy enough to
> work around.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> include/linux/fs.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 398cf20a706d..782c2a292fd7 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2645,7 +2645,7 @@ static const char * const kernel_read_file_str[] = {
>
> static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
> {
> - if (id < 0 || id >= READING_MAX_ID)
> + if ((unsigned)id >= READING_MAX_ID)
> return kernel_read_file_str[READING_UNKNOWN];
>
> return kernel_read_file_str[id];
> --
> 2.9.0
>
next prev parent reply other threads:[~2017-01-03 22:47 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-16 10:56 [RFC] minimum gcc version for kernel: raise to gcc-4.3 or 4.6? Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 01/13] [HACK] gcc-4.5: avoid link errors for unused function pointers Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 02/13] KVM: arm: fix gcc-4.5 build Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2017-01-04 10:38 ` Christoffer Dall
2017-01-04 10:38 ` Christoffer Dall
2016-12-16 10:56 ` [PATCH 03/13] ARM: div64: fix building with gcc-4.5 and lower Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 04/13] vfio-pci: use 32-bit comparisons for register address for gcc-4.5 Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 15:30 ` Alex Williamson
2016-12-16 19:50 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 05/13] clk: pxa: fix gcc-4.4 build Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 06/13] ARM: atomic: " Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 07/13] watchdog: kempld: fix gcc-4.3 build Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 08/13] arm/arm64: xen: avoid gcc-4.4 warning Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 09/13] ARM: mark cmpxchg and xchg __always_inline for gcc-4.3 Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 10/13] asm-generic: mark cmpxchg as " Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 10:56 ` [PATCH 11/13] fs: fix unsigned enum warning with gcc-4.2 Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2017-01-03 22:47 ` Brendan Gregg [this message]
2017-02-28 21:53 ` Brendan Gregg
2016-12-16 10:56 ` [PATCH 12/13] KVM: arm: avoid binary number literals for gcc-4.2 Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2017-01-04 10:39 ` Christoffer Dall
2017-01-04 10:39 ` Christoffer Dall
2016-12-16 10:56 ` [PATCH 13/13] ARM: avoid 'Q' asm constraint for gcc-4.1 and earlier Arnd Bergmann
2016-12-16 10:56 ` Arnd Bergmann
2016-12-16 11:14 ` [RFC] minimum gcc version for kernel: raise to gcc-4.3 or 4.6? Arnd Bergmann
2016-12-16 11:14 ` Arnd Bergmann
2017-04-16 19:52 ` Kees Cook
2017-04-20 10:15 ` Arnd Bergmann
2017-04-20 19:52 ` Kees Cook
2017-04-20 19:52 ` Kees Cook
2017-04-21 20:55 ` Arnd Bergmann
2017-04-21 20:55 ` Arnd Bergmann
2017-04-21 21:05 ` Kees Cook
2017-04-21 21:05 ` Kees Cook
2017-04-22 3:10 ` Maciej W. Rozycki
2017-04-22 3:10 ` Maciej W. Rozycki
2017-04-22 15:30 ` Arnd Bergmann
2017-04-22 15:30 ` Arnd Bergmann
2017-04-23 20:13 ` Geert Uytterhoeven
2017-04-23 20:13 ` Geert Uytterhoeven
2017-04-24 9:44 ` Arnd Bergmann
2017-04-24 9:44 ` Arnd Bergmann
2017-04-24 10:17 ` Geert Uytterhoeven
2017-04-24 10:17 ` Geert Uytterhoeven
2017-04-24 14:13 ` Arnd Bergmann
2017-04-24 16:53 ` Maciej W. Rozycki
2017-04-24 17:29 ` Arnd Bergmann
2017-04-24 18:16 ` Geert Uytterhoeven
2017-04-24 18:16 ` Geert Uytterhoeven
2017-04-24 18:30 ` Maciej W. Rozycki
2017-04-24 18:30 ` Maciej W. Rozycki
2017-04-24 20:30 ` Arnd Bergmann
2017-04-24 20:52 ` Kees Cook
2017-04-25 7:06 ` Geert Uytterhoeven
2017-04-25 7:06 ` Geert Uytterhoeven
2017-04-25 9:22 ` Suzuki K Poulose
2017-04-25 9:22 ` Suzuki K Poulose
2016-12-16 15:54 ` Geert Uytterhoeven
2016-12-16 15:54 ` Geert Uytterhoeven
2016-12-16 19:58 ` Arnd Bergmann
2016-12-16 19:58 ` Arnd Bergmann
2016-12-16 20:34 ` Geert Uytterhoeven
2016-12-16 20:34 ` Geert Uytterhoeven
2016-12-16 17:00 ` Sebastian Andrzej Siewior
2016-12-16 22:00 ` Arnd Bergmann
2016-12-16 22:00 ` Arnd Bergmann
2016-12-17 11:29 ` Sebastian Andrzej Siewior
2016-12-17 11:29 ` Sebastian Andrzej Siewior
2017-01-02 12:23 ` Russell King - ARM Linux
2017-01-02 12:23 ` Russell King - ARM Linux
2016-12-20 9:59 ` Heiko Carstens
2016-12-20 9:59 ` Heiko Carstens
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