From: Arnd Bergmann <arnd@arndb.de> To: linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org> Cc: Pratyush Anand <panand@redhat.com>, Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, dri-devel@lists.freedesktop.org, linux-ide@vger.kernel.org, Tejun Heo <tj@kernel.org>, akpm@linux-foundation.org, Linus Torvalds <torvalds@linux-foundation.org>, Ingo Molnar <mingo@kernel.org>, Guenter Roeck <linux@roeck-us.net>, linux-media@vger.kernel.org Subject: [PATCH 07/14] proc/kcore: hide a harmless warning Date: Fri, 14 Jul 2017 11:25:19 +0200 [thread overview] Message-ID: <20170714092540.1217397-8-arnd@arndb.de> (raw) In-Reply-To: <20170714092540.1217397-1-arnd@arndb.de> gcc warns when MODULES_VADDR/END is defined to the same value as VMALLOC_START/VMALLOC_END, e.g. on x86-32: fs/proc/kcore.c: In function ‘add_modules_range’: fs/proc/kcore.c:622:161: error: self-comparison always evaluates to false [-Werror=tautological-compare] if (/*MODULES_VADDR != VMALLOC_START && */MODULES_END != VMALLOC_END) { The code is correct as it is required for most other configurations. The best workaround I found for shutting up that warning is to make it a little more complex by adding a temporary variable. The compiler will still optimize away the code as it finds the two to be identical, but it no longer warns because it doesn't condider the comparison "tautological" any more. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- fs/proc/kcore.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index 45629f4b5402..c503ad657c46 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -620,12 +620,14 @@ static void __init proc_kcore_text_init(void) /* * MODULES_VADDR has no intersection with VMALLOC_ADDR. */ -struct kcore_list kcore_modules; +static struct kcore_list kcore_modules; static void __init add_modules_range(void) { - if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) { - kclist_add(&kcore_modules, (void *)MODULES_VADDR, - MODULES_END - MODULES_VADDR, KCORE_VMALLOC); + void *start = (void *)MODULES_VADDR; + size_t len = MODULES_END - MODULES_VADDR; + + if (start != (void *)VMALLOC_START && len != VMALLOC_END - VMALLOC_START) { + kclist_add(&kcore_modules, start, len, KCORE_VMALLOC); } } #else -- 2.9.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de> To: linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, Tejun Heo <tj@kernel.org>, Guenter Roeck <linux@roeck-us.net>, linux-ide@vger.kernel.org, linux-media@vger.kernel.org, akpm@linux-foundation.org, dri-devel@lists.freedesktop.org, Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>, Ingo Molnar <mingo@kernel.org>, Laura Abbott <labbott@redhat.com>, Pratyush Anand <panand@redhat.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org> Subject: [PATCH 07/14] proc/kcore: hide a harmless warning Date: Fri, 14 Jul 2017 11:25:19 +0200 [thread overview] Message-ID: <20170714092540.1217397-8-arnd@arndb.de> (raw) In-Reply-To: <20170714092540.1217397-1-arnd@arndb.de> gcc warns when MODULES_VADDR/END is defined to the same value as VMALLOC_START/VMALLOC_END, e.g. on x86-32: fs/proc/kcore.c: In function ‘add_modules_range’: fs/proc/kcore.c:622:161: error: self-comparison always evaluates to false [-Werror=tautological-compare] if (/*MODULES_VADDR != VMALLOC_START && */MODULES_END != VMALLOC_END) { The code is correct as it is required for most other configurations. The best workaround I found for shutting up that warning is to make it a little more complex by adding a temporary variable. The compiler will still optimize away the code as it finds the two to be identical, but it no longer warns because it doesn't condider the comparison "tautological" any more. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- fs/proc/kcore.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index 45629f4b5402..c503ad657c46 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -620,12 +620,14 @@ static void __init proc_kcore_text_init(void) /* * MODULES_VADDR has no intersection with VMALLOC_ADDR. */ -struct kcore_list kcore_modules; +static struct kcore_list kcore_modules; static void __init add_modules_range(void) { - if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) { - kclist_add(&kcore_modules, (void *)MODULES_VADDR, - MODULES_END - MODULES_VADDR, KCORE_VMALLOC); + void *start = (void *)MODULES_VADDR; + size_t len = MODULES_END - MODULES_VADDR; + + if (start != (void *)VMALLOC_START && len != VMALLOC_END - VMALLOC_START) { + kclist_add(&kcore_modules, start, len, KCORE_VMALLOC); } } #else -- 2.9.0
next prev parent reply other threads:[~2017-07-14 9:25 UTC|newest] Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-07-14 9:25 [PATCH 00/14] gcc-7 warnings Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-14 9:25 ` [PATCH, RESEND 01/14] ide: avoid warning for timings calculation Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-14 9:25 ` [PATCH, RESEND 02/14] ata: avoid gcc-7 warning in ata_timing_quantize Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-15 10:56 ` Tejun Heo 2017-07-15 10:56 ` Tejun Heo 2017-07-14 9:25 ` [PATCH, RESEND 03/14] drm/vmwgfx: avoid gcc-7 parentheses warning Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-14 10:11 ` Jani Nikula 2017-07-14 10:11 ` Jani Nikula 2017-07-14 19:21 ` Linus Torvalds 2017-07-14 19:21 ` Linus Torvalds 2017-07-14 19:23 ` Linus Torvalds 2017-07-14 20:28 ` Arnd Bergmann 2017-07-17 13:15 ` Sinclair Yeh 2017-07-17 13:15 ` Sinclair Yeh 2017-07-14 9:25 ` [PATCH 04/14] x86: math-emu: avoid -Wint-in-bool-context warning Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-14 9:25 ` [PATCH 05/14] isdn: isdnloop: suppress a gcc-7 warning Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-14 10:08 ` Joe Perches 2017-07-14 10:37 ` Arnd Bergmann 2017-07-15 4:20 ` Kevin Easton 2017-07-14 9:25 ` [PATCH 06/14] acpi: thermal: fix gcc-6/ccache warning Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann [this message] 2017-07-14 9:25 ` [PATCH 07/14] proc/kcore: hide a harmless warning Arnd Bergmann 2017-07-14 12:28 ` Ard Biesheuvel 2017-07-18 19:53 ` Arnd Bergmann 2017-07-18 19:53 ` Arnd Bergmann 2017-07-18 19:55 ` Ard Biesheuvel 2017-07-18 20:01 ` Arnd Bergmann 2017-07-18 20:07 ` Ard Biesheuvel 2017-07-18 20:21 ` Arnd Bergmann 2017-07-14 9:25 ` [PATCH 08/14] Input: adxl34x - fix gcc-7 -Wint-in-bool-context warning Arnd Bergmann 2017-07-14 9:25 ` Arnd Bergmann 2017-07-14 19:24 ` Linus Torvalds 2017-07-14 20:17 ` Arnd Bergmann 2017-07-14 21:40 ` Dmitry Torokhov 2017-07-14 9:30 ` [PATCH 09/14] SFI: fix tautological-compare warning Arnd Bergmann 2017-07-14 9:30 ` Arnd Bergmann 2017-07-14 9:31 ` [PATCH 10/14] staging:iio:resolver:ad2s1210 fix negative IIO_ANGL_VEL read Arnd Bergmann 2017-07-14 9:31 ` Arnd Bergmann 2017-07-15 11:42 ` Jonathan Cameron 2017-07-14 9:31 ` [PATCH 11/14] IB/uverbs: fix gcc-7 type warning Arnd Bergmann 2017-07-14 9:31 ` Arnd Bergmann 2017-07-14 9:46 ` Leon Romanovsky 2017-07-14 9:31 ` [PATCH 12/14] drm/nouveau/clk: fix gcc-7 -Wint-in-bool-context warning Arnd Bergmann 2017-07-14 9:31 ` Arnd Bergmann 2017-07-14 9:31 ` [PATCH 13/14] iopoll: avoid " Arnd Bergmann 2017-07-14 9:31 ` Arnd Bergmann 2017-07-14 9:55 ` Joe Perches 2017-07-14 10:22 ` Arnd Bergmann 2017-07-14 9:36 ` [PATCH 14/14] [media] fix warning on v4l2_subdev_call() result interpreted as bool Arnd Bergmann 2017-07-14 9:36 ` Arnd Bergmann 2017-07-14 9:36 ` Arnd Bergmann 2017-07-14 12:05 ` Dan Carpenter 2017-07-14 12:05 ` Dan Carpenter 2017-07-14 12:05 ` Dan Carpenter 2017-07-14 12:27 ` Arnd Bergmann 2017-07-14 12:27 ` Arnd Bergmann 2017-07-14 12:27 ` Arnd Bergmann 2017-07-14 12:55 ` Dan Carpenter 2017-07-14 12:55 ` Dan Carpenter 2017-07-14 12:55 ` Dan Carpenter 2017-07-14 13:09 ` Dan Carpenter 2017-07-14 13:09 ` Dan Carpenter 2017-07-14 13:09 ` Dan Carpenter 2017-07-14 19:32 ` Arnd Bergmann 2017-07-14 19:32 ` Arnd Bergmann 2017-07-14 19:32 ` Arnd Bergmann 2017-07-14 12:41 ` Dan Carpenter 2017-07-14 12:41 ` Dan Carpenter 2017-07-14 12:41 ` Dan Carpenter 2017-07-17 13:45 ` Hans Verkuil 2017-07-17 13:45 ` Hans Verkuil 2017-07-17 14:26 ` Arnd Bergmann 2017-07-17 14:26 ` Arnd Bergmann 2017-07-17 14:26 ` Arnd Bergmann 2017-07-17 14:28 ` Dan Carpenter 2017-07-17 14:28 ` Dan Carpenter 2017-07-17 14:28 ` Dan Carpenter 2017-07-17 14:32 ` Hans Verkuil 2017-07-17 14:32 ` Hans Verkuil 2017-07-17 14:32 ` Hans Verkuil 2017-07-17 14:35 ` Hans Verkuil 2017-07-17 14:35 ` Hans Verkuil 2017-07-17 14:35 ` Hans Verkuil 2017-07-17 21:23 ` Arnd Bergmann 2017-07-17 21:23 ` Arnd Bergmann 2017-07-17 21:23 ` Arnd Bergmann 2017-07-14 10:29 ` [PATCH 00/14] gcc-7 warnings Greg Kroah-Hartman 2017-07-14 10:29 ` Greg Kroah-Hartman
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