linux-kernel - Re: [PATCH] uio.c: Fix warning: 'ret' might be used uninitialized

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <201211271424.45588.vitas@nppfactor.kiev.ua>
Date:	Tue, 27 Nov 2012 14:24:45 +0200
From:	Vitalii Demianets <vitas@...factor.kiev.ua>
To:	linux-kernel@...r.kernel.org
Cc:	"Hans J. Koch" <hjk@...sjkoch.de>,
	"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] uio.c: Fix warning: 'ret' might be used uninitialized

By the way, I've found that warning while working on the older kernel with 
older gcc (ver. 3.4.4). The modern gcc (ver. 4.5.4) does not emit that 
warning no matter how hard I try. For example, it does not warn even with the 
following line in the drivers/uio/Makefile:

  ccflags-$(CONFIG_UIO) += -O2 -Wall -Wextra -Wuninitialized

In that case the actual command line looks like (from "make V=1" output):

gcc -Wp,-MD,drivers/uio/.uio.o.d  -nostdinc -isystem /usr/lib/gcc/x86_64-pc-linux-gnu/4.5.4/include -I/home/vitas/Progs/net-next/net-next/arch/x86/include -Iarch/x86/include/generated  -Iinclude -I/home/vitas/Progs/net-next/net-next/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/vitas/Progs/net-next/net-next/include/uapi -Iinclude/generated/uapi -include /home/vitas/Progs/net-next/net-next/include/linux/kconfig.h -D__KERNEL__ -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -Werror-implicit-function-declaration -Wno-format-security -fno-delete-null-pointer-checks -O2 -m64 -mtune=generic -mno-red-zone -mcmodel=kernel -funit-at-a-time -maccumulate-outgoing-args -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1 -DCONFIG_AS_CFI_SECTIONS=1 -DCONFIG_AS_FXSAVEQ=1 -DCONFIG_AS_AVX=1 -pipe -Wno-sign-compare -fno-asynchronous-unwind-tables -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -Wframe-larger-than=2048 -fno-stack-protector -fno-omit-frame-pointer -fno-optimize-sibling-calls -Wdeclaration-after-statement -Wno-pointer-sign -fno-strict-overflow -fconserve-stack -DCC_HAVE_ASM_GOTO -O2 -Wall -Wextra -Wuninitialized    -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(uio)"  -D"KBUILD_MODNAME=KBUILD_STR(uio)" -c -o 
drivers/uio/uio.o drivers/uio/uio.c

I wander why doesn't modern gcc warn about obvious use of uninitialized 
variable. Is it some known regression in gcc?

-- 
With Best Regards,
Vitalii Demianets
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/