2023-02-10 03:53:27

by kernel test robot

[permalink] [raw]
Subject: arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 38c1e0c65865426676123cc9a127526fa02bcac6
commit: 2f44013e39984c127c6efedf70e6b5f4e9dcf315 erofs: fix pcluster use-after-free on UP platforms
date: 5 months ago
config: alpha-randconfig-s042-20230210 (https://download.01.org/0day-ci/archive/20230210/[email protected]/config)
compiler: alpha-linux-gcc (GCC) 12.1.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.4-39-gce1a6720-dirty
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2f44013e39984c127c6efedf70e6b5f4e9dcf315
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 2f44013e39984c127c6efedf70e6b5f4e9dcf315
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=alpha olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=alpha SHELL=/bin/bash fs/erofs/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/

sparse warnings: (new ones prefixed by >>)
fs/erofs/utils.c: note: in included file (through arch/alpha/include/asm/cmpxchg.h, arch/alpha/include/asm/atomic.h, include/linux/atomic.h, ...):
>> arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)
>> arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes 10cc)
--
fs/erofs/zdata.c: note: in included file (through arch/alpha/include/asm/cmpxchg.h, arch/alpha/include/asm/atomic.h, include/linux/atomic.h, ...):
>> arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)
>> arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes 10cc)
arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes fe)
arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes cafe)
arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes fe)
arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (5f0edead becomes ad)
arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes cafe)
arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (5f0edead becomes dead)

vim +234 arch/alpha/include/asm/xchg.h

a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 227
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 228 static __always_inline unsigned long
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 229 ____cmpxchg(, volatile void *ptr, unsigned long old, unsigned long new,
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 230 int size)
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 231 {
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 232 switch (size) {
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 233 case 1:
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 @234 return ____cmpxchg(_u8, ptr, old, new);
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 235 case 2:
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 @236 return ____cmpxchg(_u16, ptr, old, new);
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 237 case 4:
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 238 return ____cmpxchg(_u32, ptr, old, new);
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 239 case 8:
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 240 return ____cmpxchg(_u64, ptr, old, new);
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 241 }
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 242 __cmpxchg_called_with_bad_pointer();
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 243 return old;
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 244 }
a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 245

:::::: The code at line 234 was first introduced by commit
:::::: a6209d6d71f2ab8c63cc1587ef65490d83022baf alpha: xchg/cmpxchg cleanup and fixes

:::::: TO: Ivan Kokshaysky <[email protected]>
:::::: CC: Linus Torvalds <[email protected]>

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests


2023-02-10 03:59:28

by Gao Xiang

[permalink] [raw]
Subject: Re: arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)

Hi,

On 2023/2/10 11:52, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 38c1e0c65865426676123cc9a127526fa02bcac6
> commit: 2f44013e39984c127c6efedf70e6b5f4e9dcf315 erofs: fix pcluster use-after-free on UP platforms
> date: 5 months ago
> config: alpha-randconfig-s042-20230210 (https://download.01.org/0day-ci/archive/20230210/[email protected]/config)
> compiler: alpha-linux-gcc (GCC) 12.1.0
> reproduce:
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # apt-get install sparse
> # sparse version: v0.6.4-39-gce1a6720-dirty
> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2f44013e39984c127c6efedf70e6b5f4e9dcf315
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout 2f44013e39984c127c6efedf70e6b5f4e9dcf315
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=alpha olddefconfig
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=alpha SHELL=/bin/bash fs/erofs/
>
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <[email protected]>
> | Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/
>
> sparse warnings: (new ones prefixed by >>)
> fs/erofs/utils.c: note: in included file (through arch/alpha/include/asm/cmpxchg.h, arch/alpha/include/asm/atomic.h, include/linux/atomic.h, ...):
>>> arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)
>>> arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes 10cc)
> --
> fs/erofs/zdata.c: note: in included file (through arch/alpha/include/asm/cmpxchg.h, arch/alpha/include/asm/atomic.h, include/linux/atomic.h, ...):
>>> arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes cc)
>>> arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (ffffffffe0f510cc becomes 10cc)
> arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes fe)
> arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes cafe)
> arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes fe)
> arch/alpha/include/asm/xchg.h:234:32: sparse: sparse: cast truncates bits from constant value (5f0edead becomes ad)
> arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (5f0ecafe becomes cafe)
> arch/alpha/include/asm/xchg.h:236:32: sparse: sparse: cast truncates bits from constant value (5f0edead becomes dead)

As I reported in
https://lore.kernel.org/r/[email protected]

I'm not sure how we could do something for these reports in EROFS.

Thanks,
Gao Xiang

>
> vim +234 arch/alpha/include/asm/xchg.h
>
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 227
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 228 static __always_inline unsigned long
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 229 ____cmpxchg(, volatile void *ptr, unsigned long old, unsigned long new,
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 230 int size)
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 231 {
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 232 switch (size) {
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 233 case 1:
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 @234 return ____cmpxchg(_u8, ptr, old, new);
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 235 case 2:
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 @236 return ____cmpxchg(_u16, ptr, old, new);
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 237 case 4:
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 238 return ____cmpxchg(_u32, ptr, old, new);
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 239 case 8:
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 240 return ____cmpxchg(_u64, ptr, old, new);
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 241 }
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 242 __cmpxchg_called_with_bad_pointer();
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 243 return old;
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 244 }
> a6209d6d71f2ab Ivan Kokshaysky 2009-03-31 245
>
> :::::: The code at line 234 was first introduced by commit
> :::::: a6209d6d71f2ab8c63cc1587ef65490d83022baf alpha: xchg/cmpxchg cleanup and fixes
>
> :::::: TO: Ivan Kokshaysky <[email protected]>
> :::::: CC: Linus Torvalds <[email protected]>
>