tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: 03933bd11a64b94203f2cbe30ae71061807872fb commit: 1a378b87531ea80e7847bf0105adedff28a73080 [16561/22602] mm: add pin memory method for checkpoint add restore config: arm64-randconfig-002-20240531 (https://download.01.org/0day-ci/archive/20240531/202405310530.QbRwB9XW-lkp@i...) compiler: aarch64-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240531/202405310530.QbRwB9XW-lkp@i...)

If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202405310530.QbRwB9XW-lkp@intel.com/

Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

In file included from include/linux/compat.h:19, from arch/arm64/include/asm/ftrace.h:20, from include/linux/ftrace.h:21, from include/linux/kprobes.h:42, from drivers/char/pin_memory.c:8: In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'set_pin_mem_area' at drivers/char/pin_memory.c:95:6:

...

include/linux/uaccess.h:112:17: warning: 'pmas' may be used uninitialized [-Wmaybe-uninitialized]

112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/compiler.h:251, from include/linux/export.h:45, from include/linux/linkage.h:7, from include/linux/kernel.h:7, from drivers/char/pin_memory.c:6: include/linux/kasan-checks.h: In function 'set_pin_mem_area': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/char/pin_memory.c:90:33: note: 'pmas' declared here 90 | struct pin_mem_area_set pmas; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'pin_mem_remap' at drivers/char/pin_memory.c:116:6:

...

include/linux/uaccess.h:112:17: warning: 'pid' may be used uninitialized [-Wmaybe-uninitialized]

112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'pin_mem_remap': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here 7 | void kasan_check_write(const volatile void *p, unsigned int size); | ^~~~~~~~~~~~~~~~~ drivers/char/pin_memory.c:107:13: note: 'pid' declared here 107 | int pid; | ^~~

Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for HARDLOCKUP_DETECTOR Depends on [n]: DEBUG_KERNEL [=n] && !S390 && (HAVE_HARDLOCKUP_DETECTOR_PERF [=n] || HAVE_HARDLOCKUP_DETECTOR_ARCH [=y]) Selected by [y]: - SDEI_WATCHDOG [=y] && <choice> && ARM_SDE_INTERFACE [=y] && !HARDLOCKUP_CHECK_TIMESTAMP [=n]

vim +/pmas +112 include/linux/uaccess.h

d597580d373774 Al Viro 2017-03-20 104 d597580d373774 Al Viro 2017-03-20 105 #ifdef INLINE_COPY_FROM_USER d597580d373774 Al Viro 2017-03-20 106 static inline unsigned long d597580d373774 Al Viro 2017-03-20 107 _copy_from_user(void *to, const void __user *from, unsigned long n) d597580d373774 Al Viro 2017-03-20 108 { d597580d373774 Al Viro 2017-03-20 109 unsigned long res = n; 9c5f6908de03a4 Al Viro 2017-06-29 110 might_fault(); 4983cb67a383a7 Linus Torvalds 2019-02-14 111 if (likely(access_ok(from, n))) { 9c5f6908de03a4 Al Viro 2017-06-29 @112 kasan_check_write(to, n); d597580d373774 Al Viro 2017-03-20 113 res = raw_copy_from_user(to, from, n); 9c5f6908de03a4 Al Viro 2017-06-29 114 } d597580d373774 Al Viro 2017-03-20 115 if (unlikely(res)) d597580d373774 Al Viro 2017-03-20 116 memset(to + (n - res), 0, res); d597580d373774 Al Viro 2017-03-20 117 return res; d597580d373774 Al Viro 2017-03-20 118 } d597580d373774 Al Viro 2017-03-20 119 #else d597580d373774 Al Viro 2017-03-20 120 extern unsigned long d597580d373774 Al Viro 2017-03-20 121 _copy_from_user(void *, const void __user *, unsigned long); d597580d373774 Al Viro 2017-03-20 122 #endif d597580d373774 Al Viro 2017-03-20 123 d597580d373774 Al Viro 2017-03-20 124 #ifdef INLINE_COPY_TO_USER d597580d373774 Al Viro 2017-03-20 125 static inline unsigned long d597580d373774 Al Viro 2017-03-20 126 _copy_to_user(void __user *to, const void *from, unsigned long n) d597580d373774 Al Viro 2017-03-20 127 { 9c5f6908de03a4 Al Viro 2017-06-29 128 might_fault(); 4983cb67a383a7 Linus Torvalds 2019-02-14 129 if (access_ok(to, n)) { 9c5f6908de03a4 Al Viro 2017-06-29 130 kasan_check_read(from, n); d597580d373774 Al Viro 2017-03-20 131 n = raw_copy_to_user(to, from, n); 9c5f6908de03a4 Al Viro 2017-06-29 132 } d597580d373774 Al Viro 2017-03-20 133 return n; d597580d373774 Al Viro 2017-03-20 134 } d597580d373774 Al Viro 2017-03-20 135 #else d597580d373774 Al Viro 2017-03-20 136 extern unsigned long d597580d373774 Al Viro 2017-03-20 137 _copy_to_user(void __user *, const void *, unsigned long); d597580d373774 Al Viro 2017-03-20 138 #endif d597580d373774 Al Viro 2017-03-20 139 d597580d373774 Al Viro 2017-03-20 140 static __always_inline unsigned long __must_check d597580d373774 Al Viro 2017-03-20 141 copy_from_user(void *to, const void __user *from, unsigned long n) d597580d373774 Al Viro 2017-03-20 142 { b0377fedb65280 Al Viro 2017-06-29 143 if (likely(check_copy_size(to, n, false))) d597580d373774 Al Viro 2017-03-20 @144 n = _copy_from_user(to, from, n); d597580d373774 Al Viro 2017-03-20 145 return n; d597580d373774 Al Viro 2017-03-20 146 } d597580d373774 Al Viro 2017-03-20 147

:::::: The code at line 112 was first introduced by commit :::::: 9c5f6908de03a4f52ba7364b11fcd6116225480c copy_{from,to}_user(): move kasan checks and might_fault() out-of-line

:::::: TO: Al Viro viro@zeniv.linux.org.uk :::::: CC: Al Viro viro@zeniv.linux.org.uk