From: kernel test robot <lkp@intel.com>
To: kbuild@lists.01.org
Subject: arch/x86/kernel/fpu/xstate.c:1785:3: warning: Value stored to 'guest' is never read [clang-analyzer-deadcode.DeadStores]
Date: Fri, 28 Jan 2022 21:42:20 +0800 [thread overview]
Message-ID: <202201282146.AWOcMJwk-lkp@intel.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 19062 bytes --]
CC: llvm(a)lists.linux.dev
CC: kbuild-all(a)lists.01.org
CC: linux-kernel(a)vger.kernel.org
TO: Thomas Gleixner <tglx@linutronix.de>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Jing Liu <jing2.liu@intel.com>
CC: Yang Zhong <yang.zhong@intel.com>
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 23a46422c56144939c091c76cf389aa863ce9c18
commit: 980fe2fddcff21937c93532b4597c8ea450346c1 x86/fpu: Extend fpu_xstate_prctl() with guest permissions
date: 3 weeks ago
:::::: branch date: 19 hours ago
:::::: commit date: 3 weeks ago
config: i386-randconfig-c001 (https://download.01.org/0day-ci/archive/20220128/202201282146.AWOcMJwk-lkp(a)intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project f7b7138a62648f4019c55e4671682af1f851f295)
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
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=980fe2fddcff21937c93532b4597c8ea450346c1
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 980fe2fddcff21937c93532b4597c8ea450346c1
# save the config file to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=i386 clang-analyzer
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
clang-analyzer warnings: (new ones prefixed by >>)
^
kernel/trace/ring_buffer.c:1055:4: note: expanded from macro 'RB_WARN_ON'
if (__same_type(*(b), struct ring_buffer_per_cpu)) { \
^
kernel/trace/ring_buffer.c:3499:3: note: Taking true branch
RB_WARN_ON(cpu_buffer, !s_ok);
^
kernel/trace/ring_buffer.c:1061:4: note: expanded from macro 'RB_WARN_ON'
WARN_ON(1); \
^
include/asm-generic/bug.h:122:2: note: expanded from macro 'WARN_ON'
if (unlikely(__ret_warn_on)) \
^
kernel/trace/ring_buffer.c:3499:3: note: Loop condition is false. Exiting loop
RB_WARN_ON(cpu_buffer, !s_ok);
^
kernel/trace/ring_buffer.c:1061:4: note: expanded from macro 'RB_WARN_ON'
WARN_ON(1); \
^
include/asm-generic/bug.h:123:3: note: expanded from macro 'WARN_ON'
__WARN(); \
^
include/asm-generic/bug.h:96:19: note: expanded from macro '__WARN'
#define __WARN() __WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
^
arch/x86/include/asm/bug.h:78:2: note: expanded from macro '__WARN_FLAGS'
instrumentation_begin(); \
^
include/linux/instrumentation.h:57:34: note: expanded from macro 'instrumentation_begin'
# define instrumentation_begin() do { } while(0)
^
kernel/trace/ring_buffer.c:3499:3: note: Loop condition is false. Exiting loop
RB_WARN_ON(cpu_buffer, !s_ok);
^
kernel/trace/ring_buffer.c:1061:4: note: expanded from macro 'RB_WARN_ON'
WARN_ON(1); \
^
include/asm-generic/bug.h:123:3: note: expanded from macro 'WARN_ON'
__WARN(); \
^
include/asm-generic/bug.h:96:19: note: expanded from macro '__WARN'
#define __WARN() __WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
^
arch/x86/include/asm/bug.h:79:2: note: expanded from macro '__WARN_FLAGS'
_BUG_FLAGS(ASM_UD2, BUGFLAG_WARNING|(flags)); \
^
arch/x86/include/asm/bug.h:25:37: note: expanded from macro '_BUG_FLAGS'
#define _BUG_FLAGS(ins, flags) \
^
kernel/trace/ring_buffer.c:3499:3: note: Loop condition is false. Exiting loop
RB_WARN_ON(cpu_buffer, !s_ok);
^
kernel/trace/ring_buffer.c:1061:4: note: expanded from macro 'RB_WARN_ON'
WARN_ON(1); \
^
include/asm-generic/bug.h:123:3: note: expanded from macro 'WARN_ON'
__WARN(); \
^
include/asm-generic/bug.h:96:19: note: expanded from macro '__WARN'
#define __WARN() __WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
^
arch/x86/include/asm/bug.h:81:2: note: expanded from macro '__WARN_FLAGS'
instrumentation_end(); \
^
include/linux/instrumentation.h:58:33: note: expanded from macro 'instrumentation_end'
# define instrumentation_end() do { } while(0)
^
kernel/trace/ring_buffer.c:3499:3: note: Loop condition is false. Exiting loop
RB_WARN_ON(cpu_buffer, !s_ok);
^
kernel/trace/ring_buffer.c:1061:4: note: expanded from macro 'RB_WARN_ON'
WARN_ON(1); \
^
include/asm-generic/bug.h:123:3: note: expanded from macro 'WARN_ON'
__WARN(); \
^
include/asm-generic/bug.h:96:19: note: expanded from macro '__WARN'
#define __WARN() __WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
^
arch/x86/include/asm/bug.h:76:33: note: expanded from macro '__WARN_FLAGS'
#define __WARN_FLAGS(flags) \
^
kernel/trace/ring_buffer.c:3500:3: note: Taking false branch
if (likely(!(info->add_timestamp &
^
kernel/trace/ring_buffer.c:3509:25: note: The right operand of '!=' is a garbage value
if (unlikely(info->ts != save_before)) {
^
include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
# define unlikely(x) __builtin_expect(!!(x), 0)
^
Suppressed 1 warnings (1 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
1 warning generated.
Suppressed 1 warnings (1 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
1 warning generated.
Suppressed 1 warnings (1 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
1 warning generated.
>> arch/x86/kernel/fpu/xstate.c:1785:3: warning: Value stored to 'guest' is never read [clang-analyzer-deadcode.DeadStores]
guest = true;
^ ~~~~
arch/x86/kernel/fpu/xstate.c:1785:3: note: Value stored to 'guest' is never read
guest = true;
^ ~~~~
1 warning generated.
Suppressed 1 warnings (1 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
1 warning generated.
Suppressed 1 warnings (1 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
8 warnings generated.
arch/x86/kernel/cpu/cacheinfo.c:764:5: warning: Value stored to 'l2_id' is never read [clang-analyzer-deadcode.DeadStores]
l2_id = c->apicid & ~((1 << index_msb) - 1);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/kernel/cpu/cacheinfo.c:764:5: note: Value stored to 'l2_id' is never read
l2_id = c->apicid & ~((1 << index_msb) - 1);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/x86/kernel/cpu/cacheinfo.c:764:30: warning: The result of the left shift is undefined due to shifting by '4294967295', which is greater or equal to the width of type 'int' [clang-analyzer-core.UndefinedBinaryOperatorResult]
l2_id = c->apicid & ~((1 << index_msb) - 1);
^ ~~~~~~~~~
arch/x86/kernel/cpu/cacheinfo.c:732:6: note: Assuming field 'cpuid_level' is > 3
if (c->cpuid_level > 3) {
^
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:52: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
arch/x86/kernel/cpu/cacheinfo.c:732:2: note: '?' condition is false
if (c->cpuid_level > 3) {
^
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
include/linux/compiler.h:58:31: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^
arch/x86/kernel/cpu/cacheinfo.c:732:9: note: Field 'cpuid_level' is > 3
if (c->cpuid_level > 3) {
^
arch/x86/kernel/cpu/cacheinfo.c:732:2: note: '?' condition is true
if (c->cpuid_level > 3) {
^
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
include/linux/compiler.h:58:69: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^
include/linux/compiler.h:69:2: note: expanded from macro '__trace_if_value'
(cond) ? \
^
arch/x86/kernel/cpu/cacheinfo.c:732:2: note: Taking true branch
if (c->cpuid_level > 3) {
^
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
arch/x86/kernel/cpu/cacheinfo.c:735:3: note: '?' condition is false
if (is_initialized == 0) {
^
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
include/linux/compiler.h:58:31: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^
arch/x86/kernel/cpu/cacheinfo.c:735:7: note: 'is_initialized' is equal to 0
if (is_initialized == 0) {
^
include/linux/compiler.h:56:47: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^~~~
include/linux/compiler.h:58:86: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
include/linux/compiler.h:69:3: note: expanded from macro '__trace_if_value'
(cond) ? \
^~~~
arch/x86/kernel/cpu/cacheinfo.c:735:3: note: '?' condition is true
if (is_initialized == 0) {
^
include/linux/compiler.h:56:28: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
include/linux/compiler.h:58:69: note: expanded from macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^
include/linux/compiler.h:69:2: note: expanded from macro '__trace_if_value'
(cond) ? \
^
arch/x86/kernel/cpu/cacheinfo.c:735:3: note: Taking true branch
if (is_initialized == 0) {
^
include/linux/compiler.h:56:23: note: expanded from macro 'if'
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
^
arch/x86/kernel/cpu/cacheinfo.c:745:15: note: Assuming 'i' is < 'num_cache_leaves'
vim +/guest +1785 arch/x86/kernel/fpu/xstate.c
980fe2fddcff21 Thomas Gleixner 2022-01-05 1736
db8268df0983ad Chang S. Bae 2021-10-21 1737 /**
db8268df0983ad Chang S. Bae 2021-10-21 1738 * fpu_xstate_prctl - xstate permission operations
db8268df0983ad Chang S. Bae 2021-10-21 1739 * @tsk: Redundant pointer to current
db8268df0983ad Chang S. Bae 2021-10-21 1740 * @option: A subfunction of arch_prctl()
db8268df0983ad Chang S. Bae 2021-10-21 1741 * @arg2: option argument
db8268df0983ad Chang S. Bae 2021-10-21 1742 * Return: 0 if successful; otherwise, an error code
db8268df0983ad Chang S. Bae 2021-10-21 1743 *
db8268df0983ad Chang S. Bae 2021-10-21 1744 * Option arguments:
db8268df0983ad Chang S. Bae 2021-10-21 1745 *
db8268df0983ad Chang S. Bae 2021-10-21 1746 * ARCH_GET_XCOMP_SUPP: Pointer to user space u64 to store the info
db8268df0983ad Chang S. Bae 2021-10-21 1747 * ARCH_GET_XCOMP_PERM: Pointer to user space u64 to store the info
db8268df0983ad Chang S. Bae 2021-10-21 1748 * ARCH_REQ_XCOMP_PERM: Facility number requested
db8268df0983ad Chang S. Bae 2021-10-21 1749 *
db8268df0983ad Chang S. Bae 2021-10-21 1750 * For facilities which require more than one XSTATE component, the request
db8268df0983ad Chang S. Bae 2021-10-21 1751 * must be the highest state component number related to that facility,
db8268df0983ad Chang S. Bae 2021-10-21 1752 * e.g. for AMX which requires XFEATURE_XTILE_CFG(17) and
db8268df0983ad Chang S. Bae 2021-10-21 1753 * XFEATURE_XTILE_DATA(18) this would be XFEATURE_XTILE_DATA(18).
db8268df0983ad Chang S. Bae 2021-10-21 1754 */
db8268df0983ad Chang S. Bae 2021-10-21 1755 long fpu_xstate_prctl(struct task_struct *tsk, int option, unsigned long arg2)
db8268df0983ad Chang S. Bae 2021-10-21 1756 {
db8268df0983ad Chang S. Bae 2021-10-21 1757 u64 __user *uptr = (u64 __user *)arg2;
db8268df0983ad Chang S. Bae 2021-10-21 1758 u64 permitted, supported;
db8268df0983ad Chang S. Bae 2021-10-21 1759 unsigned long idx = arg2;
980fe2fddcff21 Thomas Gleixner 2022-01-05 1760 bool guest = false;
db8268df0983ad Chang S. Bae 2021-10-21 1761
db8268df0983ad Chang S. Bae 2021-10-21 1762 if (tsk != current)
db8268df0983ad Chang S. Bae 2021-10-21 1763 return -EPERM;
db8268df0983ad Chang S. Bae 2021-10-21 1764
db8268df0983ad Chang S. Bae 2021-10-21 1765 switch (option) {
db8268df0983ad Chang S. Bae 2021-10-21 1766 case ARCH_GET_XCOMP_SUPP:
db8268df0983ad Chang S. Bae 2021-10-21 1767 supported = fpu_user_cfg.max_features | fpu_user_cfg.legacy_features;
db8268df0983ad Chang S. Bae 2021-10-21 1768 return put_user(supported, uptr);
db8268df0983ad Chang S. Bae 2021-10-21 1769
db8268df0983ad Chang S. Bae 2021-10-21 1770 case ARCH_GET_XCOMP_PERM:
db8268df0983ad Chang S. Bae 2021-10-21 1771 /*
db8268df0983ad Chang S. Bae 2021-10-21 1772 * Lockless snapshot as it can also change right after the
db8268df0983ad Chang S. Bae 2021-10-21 1773 * dropping the lock.
db8268df0983ad Chang S. Bae 2021-10-21 1774 */
db8268df0983ad Chang S. Bae 2021-10-21 1775 permitted = xstate_get_host_group_perm();
db8268df0983ad Chang S. Bae 2021-10-21 1776 permitted &= XFEATURE_MASK_USER_SUPPORTED;
db8268df0983ad Chang S. Bae 2021-10-21 1777 return put_user(permitted, uptr);
db8268df0983ad Chang S. Bae 2021-10-21 1778
980fe2fddcff21 Thomas Gleixner 2022-01-05 1779 case ARCH_GET_XCOMP_GUEST_PERM:
980fe2fddcff21 Thomas Gleixner 2022-01-05 1780 permitted = xstate_get_guest_group_perm();
980fe2fddcff21 Thomas Gleixner 2022-01-05 1781 permitted &= XFEATURE_MASK_USER_SUPPORTED;
980fe2fddcff21 Thomas Gleixner 2022-01-05 1782 return put_user(permitted, uptr);
980fe2fddcff21 Thomas Gleixner 2022-01-05 1783
980fe2fddcff21 Thomas Gleixner 2022-01-05 1784 case ARCH_REQ_XCOMP_GUEST_PERM:
980fe2fddcff21 Thomas Gleixner 2022-01-05 @1785 guest = true;
980fe2fddcff21 Thomas Gleixner 2022-01-05 1786 fallthrough;
980fe2fddcff21 Thomas Gleixner 2022-01-05 1787
db8268df0983ad Chang S. Bae 2021-10-21 1788 case ARCH_REQ_XCOMP_PERM:
db8268df0983ad Chang S. Bae 2021-10-21 1789 if (!IS_ENABLED(CONFIG_X86_64))
db8268df0983ad Chang S. Bae 2021-10-21 1790 return -EOPNOTSUPP;
db8268df0983ad Chang S. Bae 2021-10-21 1791
980fe2fddcff21 Thomas Gleixner 2022-01-05 1792 return xstate_request_perm(idx, guest);
db8268df0983ad Chang S. Bae 2021-10-21 1793
db8268df0983ad Chang S. Bae 2021-10-21 1794 default:
db8268df0983ad Chang S. Bae 2021-10-21 1795 return -EINVAL;
db8268df0983ad Chang S. Bae 2021-10-21 1796 }
db8268df0983ad Chang S. Bae 2021-10-21 1797 }
db8268df0983ad Chang S. Bae 2021-10-21 1798
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
next reply other threads:[~2022-01-28 13:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-28 13:42 kernel test robot [this message]
-- strict thread matches above, loose matches on Subject: below --
2022-08-07 7:48 arch/x86/kernel/fpu/xstate.c:1785:3: warning: Value stored to 'guest' is never read [clang-analyzer-deadcode.DeadStores] kernel test robot
2022-12-01 3:53 kernel test robot
2022-12-02 11:42 kernel test robot
2022-12-03 20:53 kernel test robot
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