[v3] fs/btrfs: Fix uninitialized variable
diff mbox series

Message ID 20210420151626.6045-1-khaledromdhani216@gmail.com
State New
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Series
  • [v3] fs/btrfs: Fix uninitialized variable
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Commit Message

Khaled Romdhani April 20, 2021, 3:16 p.m. UTC
As reported by the Coverity static analysis.
The variable zone is not initialized which
may causes a failed assertion.

Addresses-Coverity: ("Uninitialized variables")
Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
---
v3: catch default as an assertion failure
as proposed by David Sterba.
---
 fs/btrfs/zoned.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

kernel test robot April 20, 2021, 9:04 p.m. UTC | #1
Hi Khaled,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on kdave/for-next]
[also build test WARNING on v5.12-rc8 next-20210420]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Khaled-ROMDHANI/fs-btrfs-Fix-uninitialized-variable/20210420-231754
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
config: arm-randconfig-r021-20210420 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project ca8eef7e3da8f750d7c7aa004fe426d1d34787ea)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/0day-ci/linux/commit/c05b2a58c9ed11bd753f1e64695bd89da715fbaa
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Khaled-ROMDHANI/fs-btrfs-Fix-uninitialized-variable/20210420-231754
        git checkout c05b2a58c9ed11bd753f1e64695bd89da715fbaa
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> fs/btrfs/zoned.c:146:2: warning: variable 'zone' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
           default:
           ^~~~~~~
   fs/btrfs/zoned.c:153:14: note: uninitialized use occurs here
           return (u32)zone;
                       ^~~~
   fs/btrfs/zoned.c:139:10: note: initialize the variable 'zone' to silence this warning
           u64 zone;
                   ^
                    = 0
   1 warning generated.


vim +/zone +146 fs/btrfs/zoned.c

   133	
   134	/*
   135	 * Get the first zone number of the superblock mirror
   136	 */
   137	static inline u32 sb_zone_number(int shift, int mirror)
   138	{
   139		u64 zone;
   140	
   141		ASSERT(mirror < BTRFS_SUPER_MIRROR_MAX);
   142		switch (mirror) {
   143		case 0: zone = 0; break;
   144		case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
   145		case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
 > 146		default:
   147			ASSERT(zone);
   148			break;
   149		}
   150	
   151		ASSERT(zone <= U32_MAX);
   152	
   153		return (u32)zone;
   154	}
   155	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot April 21, 2021, 12:07 a.m. UTC | #2
Hi Khaled,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on kdave/for-next]
[also build test WARNING on v5.12-rc8 next-20210420]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Khaled-ROMDHANI/fs-btrfs-Fix-uninitialized-variable/20210420-231754
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux.git for-next
config: s390-randconfig-r032-20210420 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project ca8eef7e3da8f750d7c7aa004fe426d1d34787ea)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # https://github.com/0day-ci/linux/commit/c05b2a58c9ed11bd753f1e64695bd89da715fbaa
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Khaled-ROMDHANI/fs-btrfs-Fix-uninitialized-variable/20210420-231754
        git checkout c05b2a58c9ed11bd753f1e64695bd89da715fbaa
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from fs/btrfs/zoned.c:5:
   In file included from include/linux/blkdev.h:26:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:80:
   include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:36:59: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
                                                             ^
   include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
   #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
                                                        ^
   In file included from fs/btrfs/zoned.c:5:
   In file included from include/linux/blkdev.h:26:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:80:
   include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
   #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
                                                        ^
   In file included from fs/btrfs/zoned.c:5:
   In file included from include/linux/blkdev.h:26:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:80:
   include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
>> fs/btrfs/zoned.c:147:10: warning: variable 'zone' is uninitialized when used here [-Wuninitialized]
                   ASSERT(zone);
                          ^~~~
   fs/btrfs/ctree.h:3420:10: note: expanded from macro 'ASSERT'
           (likely(expr) ? (void)0 : assertfail(#expr, __FILE__, __LINE__))
                   ^~~~
   include/linux/compiler.h:45:39: note: expanded from macro 'likely'
   #  define likely(x)     (__branch_check__(x, 1, __builtin_constant_p(x)))
                                             ^
   include/linux/compiler.h:33:34: note: expanded from macro '__branch_check__'
                           ______r = __builtin_expect(!!(x), expect);      \
                                                         ^
   fs/btrfs/zoned.c:139:10: note: initialize the variable 'zone' to silence this warning
           u64 zone;
                   ^
                    = 0
   13 warnings generated.


vim +/zone +147 fs/btrfs/zoned.c

   133	
   134	/*
   135	 * Get the first zone number of the superblock mirror
   136	 */
   137	static inline u32 sb_zone_number(int shift, int mirror)
   138	{
   139		u64 zone;
   140	
   141		ASSERT(mirror < BTRFS_SUPER_MIRROR_MAX);
   142		switch (mirror) {
   143		case 0: zone = 0; break;
   144		case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
   145		case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
   146		default:
 > 147			ASSERT(zone);
   148			break;
   149		}
   150	
   151		ASSERT(zone <= U32_MAX);
   152	
   153		return (u32)zone;
   154	}
   155	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Patch
diff mbox series

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 70b23a0d03b1..432509f4b3ac 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -143,6 +143,9 @@  static inline u32 sb_zone_number(int shift, int mirror)
 	case 0: zone = 0; break;
 	case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
 	case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
+	default:
+		ASSERT(zone);
+		break;
 	}
 
 	ASSERT(zone <= U32_MAX);