Hi Oleg, FYI, the error/warning still remains. tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: cc7cb040bd0afe96f1da94c9f21eda5a986510a5 commit: b77633c8236f2383f8d994249b40ed1bd3d012c0 [1420/1420] signal: simplify set_user_sigmask/restore_user_sigmask config: arm64-randconfig-r131-20250208 (https://download.01.org/0day-ci/archive/20250209/202502091307.JeeYzeRI-lkp@i...) compiler: aarch64-linux-gcc (GCC) 14.2.0 reproduce: (https://download.01.org/0day-ci/archive/20250209/202502091307.JeeYzeRI-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/202502091307.JeeYzeRI-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 >>): include/linux/compat.h:499:9: note: here 499 | case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2]; | ^~~~ include/linux/compat.h:499:58: warning: this statement may fall through [-Wimplicit-fallthrough=] 499 | case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2]; | ~~~~~~~~~^~~~~~~~~~~~~ include/linux/compat.h:500:9: note: here 500 | case 2: v.sig[3] = (set->sig[1] >> 32); v.sig[2] = set->sig[1]; | ^~~~ include/linux/compat.h:500:58: warning: this statement may fall through [-Wimplicit-fallthrough=] 500 | case 2: v.sig[3] = (set->sig[1] >> 32); v.sig[2] = set->sig[1]; | ~~~~~~~~~^~~~~~~~~~~~~ include/linux/compat.h:501:9: note: here 501 | case 1: v.sig[1] = (set->sig[0] >> 32); v.sig[0] = set->sig[0]; | ^~~~ In file included from include/asm-generic/termios.h:6, from ./arch/arm64/include/generated/uapi/asm/termios.h:1, from include/uapi/linux/termios.h:6, from include/linux/tty.h:7, from kernel/signal.c:23: In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_sigaltstack' at kernel/signal.c:3635:13, inlined from '__se_sys_sigaltstack' at kernel/signal.c:3631:1: include/linux/uaccess.h:112:17: warning: 'new' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/compiler.h:251, from include/asm-generic/bug.h:5, from arch/arm64/include/asm/bug.h:37, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/gfp.h:5, from include/linux/slab.h:15, from kernel/signal.c:13: include/linux/kasan-checks.h: In function '__se_sys_sigaltstack': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3633:17: note: 'new' declared here 3633 | stack_t new, old; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'do_compat_sigaltstack' at kernel/signal.c:3678:7: include/linux/uaccess.h:112:17: warning: 'uss32' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'do_compat_sigaltstack': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3677:32: note: 'uss32' declared here 3677 | compat_stack_t uss32; | ^~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_rt_tgsigqueueinfo' at kernel/signal.c:3496:6, inlined from '__se_sys_rt_tgsigqueueinfo' at kernel/signal.c:3491:1: include/linux/uaccess.h:112:17: warning: 'info' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function '__se_sys_rt_tgsigqueueinfo': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3494:19: note: 'info' declared here 3494 | siginfo_t info; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_rt_sigqueueinfo' at kernel/signal.c:3454:6, inlined from '__se_sys_rt_sigqueueinfo' at kernel/signal.c:3450:1: include/linux/uaccess.h:112:17: warning: 'info' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function '__se_sys_rt_sigqueueinfo': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3453:19: note: 'info' declared here 3453 | siginfo_t info; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_sigprocmask' at kernel/signal.c:3783:7, inlined from '__se_sys_sigprocmask' at kernel/signal.c:3774:1: include/linux/uaccess.h:112:17: warning: 'new_set' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function '__se_sys_sigprocmask': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3777:31: note: 'new_set' declared here 3777 | old_sigset_t old_set, new_set; | ^~~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'set_user_sigmask' at kernel/signal.c:2836:6:

...

include/linux/uaccess.h:112:17: warning: 'kmask' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'set_user_sigmask': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:2830:18: note: 'kmask' declared here 2830 | sigset_t kmask; | ^~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_rt_sigprocmask' at kernel/signal.c:2887:7, inlined from '__se_sys_rt_sigprocmask' at kernel/signal.c:2874:1, inlined from '__arm64_sys_rt_sigprocmask' at kernel/signal.c:2874:1: include/linux/uaccess.h:112:17: warning: 'new_set' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function '__arm64_sys_rt_sigprocmask': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:2877:27: note: 'new_set' declared here 2877 | sigset_t old_set, new_set; | ^~~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_rt_sigtimedwait' at kernel/signal.c:3281:6, inlined from '__se_sys_rt_sigtimedwait' at kernel/signal.c:3268:1: include/linux/uaccess.h:112:17: warning: 'these' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function '__se_sys_rt_sigtimedwait': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3272:18: note: 'these' declared here 3272 | sigset_t these; | ^~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'copy_siginfo_from_user32' at kernel/signal.c:3125:6: include/linux/uaccess.h:112:17: warning: 'from' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'copy_siginfo_from_user32': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3123:31: note: 'from' declared here 3123 | struct compat_siginfo from; | ^~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'restore_altstack' at kernel/signal.c:3648:6: include/linux/uaccess.h:112:17: warning: 'new' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'restore_altstack': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3647:17: note: 'new' declared here 3647 | stack_t new; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_rt_sigaction' at kernel/signal.c:3834:13, inlined from '__se_sys_rt_sigaction' at kernel/signal.c:3822:1, inlined from '__arm64_sys_rt_sigaction' at kernel/signal.c:3822:1: include/linux/uaccess.h:112:17: warning: 'new_sa' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function '__arm64_sys_rt_sigaction': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:3827:28: note: 'new_sa' declared here 3827 | struct k_sigaction new_sa, old_sa; | ^~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from '__do_sys_rt_sigsuspend' at kernel/signal.c:4053:6, inlined from '__se_sys_rt_sigsuspend' at kernel/signal.c:4045:1, inlined from '__arm64_sys_rt_sigsuspend' at kernel/signal.c:4045:1: include/linux/uaccess.h:112:17: warning: 'newset' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function '__arm64_sys_rt_sigsuspend': 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); | ^~~~~~~~~~~~~~~~~ kernel/signal.c:4047:18: note: 'newset' declared here 4047 | sigset_t newset; | ^~~~~~

vim +/kmask +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> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki