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b=lZ4I2loEI3M5F/Xmoj3zVD2J6ZuSsweDsJ/xzqhTlJFjWCTfOHxFT+KBERCYTt9Le o7fvlWgoUVOodSoP6O/UfQbsxRZHXc+VTlZuw/7Y6DF+od5FtlMmBPQMfaYHmFdFEC YyXnG9//5nTDgptoODd8fK2kuaKxZxl2d+xntkxKPYubFiWrcuaNQWz5nfFW6Qqwl9 GSZV/sTgccFAljLxj44mRZEo1UxeB0ZkN4wvaKIdKbyL6ZFZ5wO2UUrFP9PPOQrAEw OVQKbFVvbJZsgvGcc/zO+RsJClFFSneOl3gLBhN8ixk8VpVmXZrw1qbrhNUJarMxHl eVcyexFqm1R6A== Date: Fri, 7 Mar 2025 12:30:36 -0800 From: Kees Cook To: Jan Kara Cc: sunliming@linux.dev, viro@zeniv.linux.org.uk, brauner@kernel.org, ebiederm@xmission.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, sunliming@kylinos.cn, kernel test robot Subject: Re: [PATCH] fs: binfmt_elf_efpic: fix variable set but not used warning Message-ID: <202503071227.578545FF9@keescook> References: <20250307061128.2999222-1-sunliming@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: AB1DE14000B X-Stat-Signature: 85me8ptb8jycbd7y4bty9xrku93jtdw1 X-Rspamd-Server: rspam02 X-Rspam-User: X-HE-Tag: 1741379441-537953 X-HE-Meta: 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 lc7b5UFv kjenlaWUB8VCqrEzSNHLC7Hw5DmaDMELkaYAYzeGhywTmecSX6Yyk4KONStWDM89GPHDrQmQdxj6mO5ioziNk5mKT+dx8gTBzCGyfCARr3UvD9z5fgfPg22h5DaXl8m3e9FkgBWprifpRDcRFnBglL20XR1SnFY3TlJTesMY5vWZpJM0A7zrF2hYr1JL4IeNAj6XSVAzW6F0jYCuj4/fpsrdU/UVOYP8ZTc5z85OLzpW6VhWUfvKXegnXxvcnB5LSzlDqPMlQAuKAVLKL0JBT/32DS6hRTYeMipKGX8HK30ppdj8foPJP+K+TCtquR6AlYo5slYd+rfGH52pwUtvWDjjpqSAeLrFARTmRA7LX5hV25ozoCJezK2cpU4IDUhptMeG4 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Mar 07, 2025 at 03:47:28PM +0100, Jan Kara wrote: > On Fri 07-03-25 14:11:28, sunliming@linux.dev wrote: > > From: sunliming > > > > Fix below kernel warning: > > fs/binfmt_elf_fdpic.c:1024:52: warning: variable 'excess1' set but not > > used [-Wunused-but-set-variable] > > > > Reported-by: kernel test robot > > Signed-off-by: sunliming > > The extra ifdef is not pretty but I guess it's better. Feel free to add: > > Reviewed-by: Jan Kara Since we allow loop-scope variable definitions now, perhaps this is a case for defining the variable later within the #ifdef, like this? diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index e3cf2801cd64..b0ef71238328 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1024,7 +1024,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, /* deal with each load segment separately */ phdr = params->phdrs; for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { - unsigned long maddr, disp, excess, excess1; + unsigned long maddr, disp, excess; int prot = 0, flags; if (phdr->p_type != PT_LOAD) @@ -1120,9 +1120,10 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, * extant in the file */ excess = phdr->p_memsz - phdr->p_filesz; - excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK); #ifdef CONFIG_MMU + const unsigned long excess1 = + PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK); if (excess > excess1) { unsigned long xaddr = maddr + phdr->p_filesz + excess1; unsigned long xmaddr; > > Honza > > > --- > > fs/binfmt_elf_fdpic.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c > > index e3cf2801cd64..bed13ee8bfec 100644 > > --- a/fs/binfmt_elf_fdpic.c > > +++ b/fs/binfmt_elf_fdpic.c > > @@ -1024,8 +1024,11 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, > > /* deal with each load segment separately */ > > phdr = params->phdrs; > > for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) { > > - unsigned long maddr, disp, excess, excess1; > > + unsigned long maddr, disp, excess; > > int prot = 0, flags; > > +#ifdef CONFIG_MMU > > + unsigned long excess1; > > +#endif > > > > if (phdr->p_type != PT_LOAD) > > continue; > > @@ -1120,9 +1123,9 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, > > * extant in the file > > */ > > excess = phdr->p_memsz - phdr->p_filesz; > > - excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK); > > > > #ifdef CONFIG_MMU > > + excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK); > > if (excess > excess1) { > > unsigned long xaddr = maddr + phdr->p_filesz + excess1; > > unsigned long xmaddr; > > -- > > 2.25.1 > > > -- > Jan Kara > SUSE Labs, CR -- Kees Cook