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Mon, 29 Jul 2024 23:34:40 +0200 Message-ID: <92c6004f-9742-4abc-91bc-347cccaa44b9@gmx.com> Date: Tue, 30 Jul 2024 07:04:36 +0930 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] btrfs: initialize location to fix -Wmaybe-uninitialized in btrfs_lookup_dentry() To: David Sterba , linux-btrfs@vger.kernel.org Cc: geert@linux-m68k.org References: <20240729200608.10722-1-dsterba@suse.com> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00iVQUJDToH pgAKCRDCPZHzoSX+qNKACACkjDLzCvcFuDlgqCiS4ajHAo6twGra3uGgY2klo3S4JespWifr BLPPak74oOShqNZ8yWzB1Bkz1u93Ifx3c3H0r2vLWrImoP5eQdymVqMWmDAq+sV1Koyt8gXQ XPD2jQCrfR9nUuV1F3Z4Lgo+6I5LjuXBVEayFdz/VYK63+YLEAlSowCF72Lkz06TmaI0XMyj jgRNGM2MRgfxbprCcsgUypaDfmhY2nrhIzPUICURfp9t/65+/PLlV4nYs+DtSwPyNjkPX72+ LdyIdY+BqS8cZbPG5spCyJIlZonADojLDYQq4QnufARU51zyVjzTXMg5gAttDZwTH+8LbNI4 mm2YzsBNBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAHCwHwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00ibgUJDToHvwAK CRDCPZHzoSX+qK6vB/9yyZlsS+ijtsvwYDjGA2WhVhN07Xa5SBBvGCAycyGGzSMkOJcOtUUf tD+ADyrLbLuVSfRN1ke738UojphwkSFj4t9scG5A+U8GgOZtrlYOsY2+cG3R5vjoXUgXMP37 INfWh0KbJodf0G48xouesn08cbfUdlphSMXujCA8y5TcNyRuNv2q5Nizl8sKhUZzh4BascoK DChBuznBsucCTAGrwPgG4/ul6HnWE8DipMKvkV9ob1xJS2W4WJRPp6QdVrBWJ9cCdtpR6GbL iQi22uZXoSPv/0oUrGU+U5X4IvdnvT+8viPzszL5wXswJZfqfy8tmHM85yjObVdIG6AlnrrD In-Reply-To: <20240729200608.10722-1-dsterba@suse.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:BxWC6IVmbPYRJXt3PA7WguFR/fhV4W5lxfJFy8+D5Ej7rC39D8W 7kahLpvOWN0+LkaF26/au4mJsYBng7HyrsyvNB5TKVitUpS3/w+hS9/hKo743Ki7Ku6Dbsi EhtSO6tItkYQYEGcD6uT+Xv+NYOdtNGCkmgAA4M4MhCGNzk9a6GMPAvu42fUV93a3mIZAHh z3mwANEdVHqZxu2GPJPdg== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:dt8v9VQPuGg=;I1OHA5mTJ6FenSgXv6yOz0D5xKb yqpWHlAeXW/vCUYVGQRh6OTscF6ZlW/oHTp1ZER2Lx5pExuZC4XlNhmANJWuD2aIZeGI5qQtI FEAjOYRJ83slNuzCgxHcH7lFon3s9S/00q0beRC8XKVfE2M3lbiUzj6FF9oXORlNCwh1iGCTY AlrsruBsVBujyKmamhklfzacyvC/OYXIawI31SfFrZhGUe4TMqib0hpQ4Ldjbgv6b3QQEkoQs 0q4O3rbdmCUj5FiofvuJZaq1uahTvGSl36s68YmATqi/I5jKtZa95zMXvwaRuJk5+hZ+JpqRu 1sMulJ2BFSS2/DcauFlTBBzg5ZwEzZu1wUSFtYx6JdS1H3vuwQwiLBV0sBR1X36lp/ha0vKrM v3hpThcXgamwruz4rX0p7BxzfMD9/8SiWUYpSKi7rMsEzC2DBX1Hi6Ui73hOrvvgiQB0z9JVM M6IPMxPdiLqMHTwlJ4V+PeuBn+VVRq+BcSYLYN+2IxE26ABKEjlE81Ok4Iuq6c66mJqmkxk8i 6mAzPac4s2EfN0F5xm6sLV4+epiJKHmj7QLcLwIzOqRwxTsmsC1iswQ6rJmac6C/7LIEP94CM 27Mkz8FB21OFzzO+rUubOGMyNNawp650pdpwDbeoHM8siUUAszS3+TDdkhcjZxPQX6oryB5qM BbAk/39Z7oUavgGjXWyCEGfLTmeU3/oqvACkKq8OKn6/pqh+W+GhfXHNeNgiyqiBZb5PRXYnC RCP+VzHlhU6XrdVRxld8i8WGvrfnE+uej/FaPt5fkG4ZA7KgV5sEIbPSOgZciNWcl/JDME/QG oVzlpx4UziCBJxaSuPU9csQw== =E5=9C=A8 2024/7/30 05:36, David Sterba =E5=86=99=E9=81=93: > Some arch + compiler combinations report a potentially unused variable > location in btrfs_lookup_dentry(). This is a false alert as the variable > is passed by value and always valid or there's an error. The compilers > cannot probably reason about that although btrfs_inode_by_name() is in > the same file. > > > + /kisskb/src/fs/btrfs/inode.c: error: 'location.objectid' may be= used > +uninitialized in this function [-Werror=3Dmaybe-uninitialized]: = =3D> 5603:9 > > + /kisskb/src/fs/btrfs/inode.c: error: 'location.type' may be use= d > +uninitialized in this function [-Werror=3Dmaybe-uninitialized]: = =3D> 5674:5 > > m68k-gcc8/m68k-allmodconfig > mips-gcc8/mips-allmodconfig > powerpc-gcc5/powerpc-all{mod,yes}config > powerpc-gcc5/ppc64_defconfig > > Initialize it to zero, this should fix the warnings and won't change the > behaviour as btrfs_inode_by_name() accepts only a root or inode item > types, otherwise returns an error. > > Reported-by: Geert Uytterhoeven > Link: https://lore.kernel.org/linux-btrfs/bd4e9928-17b3-9257-8ba7-6b7f9b= bb639a@linux-m68k.org/ > Signed-off-by: David Sterba Reviewed-by: Qu Wenruo Although I hate to update our code for bad compilers, I guess it's unavoidable anyway. Thanks, Qu > --- > fs/btrfs/inode.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 32010127710d..333b0e8587a2 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -5667,7 +5667,7 @@ struct inode *btrfs_lookup_dentry(struct inode *di= r, struct dentry *dentry) > struct inode *inode; > struct btrfs_root *root =3D BTRFS_I(dir)->root; > struct btrfs_root *sub_root =3D root; > - struct btrfs_key location; > + struct btrfs_key location =3D { 0 }; > u8 di_type =3D 0; > int ret =3D 0; >