tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: bf1b7dd5d431b4248d92755c06e76094bbe2b7b4 commit: c20f651cb5a90254b561f218b967e04ff626853e [13375/21829] vt: vt_ioctl: remove unnecessary console allocation checks config: arm64-randconfig-003-20240308 (https://download.01.org/0day-ci/archive/20240311/202403110630.3gj4ph83-lkp@i...) compiler: aarch64-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240311/202403110630.3gj4ph83-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/202403110630.3gj4ph83-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/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 drivers/tty/vt/vt_ioctl.c:15: In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vt_event_wait_ioctl' at drivers/tty/vt/vt_ioctl.c:187:6: include/linux/uaccess.h:112:17: warning: 'vw' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/compiler.h:251, from include/linux/kernel.h:10, from include/linux/list.h:9, from include/linux/rculist.h:10, from include/linux/sched/signal.h:6, from drivers/tty/vt/vt_ioctl.c:14: include/linux/kasan-checks.h: In function 'vt_event_wait_ioctl': 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/tty/vt/vt_ioctl.c:185:30: note: 'vw' declared here 185 | struct vt_event_wait vw; | ^~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vt_ioctl' at drivers/tty/vt/vt_ioctl.c:450:7:

...

include/linux/uaccess.h:112:17: warning: 'kbrep' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_ioctl': 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/tty/vt/vt_ioctl.c:445:35: note: 'kbrep' declared here 445 | struct kbd_repeat kbrep; | ^~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vt_ioctl' at drivers/tty/vt/vt_ioctl.c:605:7: include/linux/uaccess.h:112:17: warning: 'tmp' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_ioctl': 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/tty/vt/vt_ioctl.c:601:32: note: 'tmp' declared here 601 | struct vt_mode tmp; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vt_ioctl' at drivers/tty/vt/vt_ioctl.c:703:7: include/linux/uaccess.h:112:17: warning: 'vsa' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_ioctl': 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/tty/vt/vt_ioctl.c:698:39: note: 'vsa' declared here 698 | struct vt_setactivate vsa; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vt_ioctl' at drivers/tty/vt/vt_ioctl.c:859:7: include/linux/uaccess.h:112:17: warning: 'v' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_ioctl': 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/tty/vt/vt_ioctl.c:856:35: note: 'v' declared here 856 | struct vt_consize v; | ^ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'do_fontx_ioctl' at drivers/tty/vt/vt_ioctl.c:246:6, inlined from 'vt_ioctl' at drivers/tty/vt/vt_ioctl.c:936:9: include/linux/uaccess.h:112:17: warning: 'cfdarg' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_ioctl': 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/tty/vt/vt_ioctl.c:243:32: note: 'cfdarg' declared here 243 | struct consolefontdesc cfdarg; | ^~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'vt_ioctl' at drivers/tty/vt/vt_ioctl.c:965:7: include/linux/uaccess.h:112:17: warning: 'op' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_ioctl': 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/tty/vt/vt_ioctl.c:352:32: note: 'op' declared here 352 | struct console_font_op op; /* used in multiple places here */ | ^~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'do_unimap_ioctl' at drivers/tty/vt/vt_ioctl.c:285:6, inlined from 'vt_ioctl' at drivers/tty/vt/vt_ioctl.c:1009:9: include/linux/uaccess.h:112:17: warning: 'tmp' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_ioctl': 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/tty/vt/vt_ioctl.c:283:27: note: 'tmp' declared here 283 | struct unimapdesc tmp; | ^~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'compat_fontx_ioctl' at drivers/tty/vt/vt_ioctl.c:1090:6, inlined from 'vt_compat_ioctl' at drivers/tty/vt/vt_ioctl.c:1202:9: include/linux/uaccess.h:112:17: warning: 'cfdarg' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_compat_ioctl': 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/tty/vt/vt_ioctl.c:1087:39: note: 'cfdarg' declared here 1087 | struct compat_consolefontdesc cfdarg; | ^~~~~~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'compat_kdfontop_ioctl' at drivers/tty/vt/vt_ioctl.c:1137:6, inlined from 'vt_compat_ioctl' at drivers/tty/vt/vt_ioctl.c:1206:9: include/linux/uaccess.h:112:17: warning: 'op' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_compat_ioctl': 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/tty/vt/vt_ioctl.c:1183:32: note: 'op' declared here 1183 | struct console_font_op op; /* used in multiple places here */ | ^~ In function '_copy_from_user', inlined from 'copy_from_user' at include/linux/uaccess.h:144:7, inlined from 'compat_unimap_ioctl' at drivers/tty/vt/vt_ioctl.c:1163:6, inlined from 'vt_compat_ioctl' at drivers/tty/vt/vt_ioctl.c:1211:9: include/linux/uaccess.h:112:17: warning: 'tmp' may be used uninitialized [-Wmaybe-uninitialized] 112 | kasan_check_write(to, n); | ^~~~~~~~~~~~~~~~~~~~~~~~ include/linux/kasan-checks.h: In function 'vt_compat_ioctl': include/linux/kasan-checks.h:7:6: note: by argument 1 of type 'const volatile void *' to 'kasan_check_write' declared here

vim +/kbrep +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 :::::: 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