tree: https://git.kernel.org/pub/scm/linux/kernel/git/jirislaby/linux.git devel head: 33533f1d99b53918d785901267d045f2964bfe5c commit: a959de21141d5d2600cdfda7c4df5fa816fb6d38 [15/52] vt: keyboard, extract and simplify vt_kdskbsent config: powerpc-allyesconfig (attached as .config) compiler: powerpc64-linux-gcc (GCC) 9.3.0 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/jirislaby/linux.git/commi... git remote add jirislaby https://git.kernel.org/pub/scm/linux/kernel/git/jirislaby/linux.git git fetch --no-tags jirislaby devel git checkout a959de21141d5d2600cdfda7c4df5fa816fb6d38 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/tty/vt/keyboard.c: In function 'vt_do_kdgkb_ioctl': drivers/tty/vt/keyboard.c:2063:3: error: 'ret' undeclared (first use in this function); did you mean 'rep'? 2063 | ret = copy_to_user(user_kdgkb->kb_string, func_copy, len + 1) ? | ^~~ | rep drivers/tty/vt/keyboard.c:2063:3: note: each undeclared identifier is reported only once for each function it appears in 2066 | kfree(func_copy); | ^~~~~~~~~~~~~~~~ drivers/tty/vt/keyboard.c:2070:2: note: here 2070 | case KDSKBSENT: { | ^~~~ vim +2066 drivers/tty/vt/keyboard.c a959de21141d5d2 Jiri Slaby 2020-08-18 2035 079c9534a96da9a Alan Cox 2012-02-28 2036 int vt_do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm) 079c9534a96da9a Alan Cox 2012-02-28 2037 { 76f8a0386a60170 Jiri Slaby 2020-08-18 2038 unsigned char kb_func; a959de21141d5d2 Jiri Slaby 2020-08-18 2039 unsigned long flags; 079c9534a96da9a Alan Cox 2012-02-28 2040 079c9534a96da9a Alan Cox 2012-02-28 2041 if (!capable(CAP_SYS_TTY_CONFIG)) 079c9534a96da9a Alan Cox 2012-02-28 2042 perm = 0; 079c9534a96da9a Alan Cox 2012-02-28 2043 76f8a0386a60170 Jiri Slaby 2020-08-18 2044 if (get_user(kb_func, &user_kdgkb->kb_func)) 0d918baecc9263e Jiri Slaby 2020-08-14 2045 return -EFAULT; 079c9534a96da9a Alan Cox 2012-02-28 2046 76f8a0386a60170 Jiri Slaby 2020-08-18 2047 kb_func = array_index_nospec(kb_func, MAX_NR_FUNC); 079c9534a96da9a Alan Cox 2012-02-28 2048 079c9534a96da9a Alan Cox 2012-02-28 2049 switch (cmd) { 8092d18a17ab730 Jiri Slaby 2020-08-14 2050 case KDGKBSENT: { 8092d18a17ab730 Jiri Slaby 2020-08-14 2051 /* size should have been a struct member */ 54b82ccf041264d Jiri Slaby 2020-09-01 2052 char *func_copy; 54b82ccf041264d Jiri Slaby 2020-09-01 2053 ssize_t len = sizeof(user_kdgkb->kb_string); 0d918baecc9263e Jiri Slaby 2020-08-14 2054 54b82ccf041264d Jiri Slaby 2020-09-01 2055 func_copy = kmalloc(len, GFP_KERNEL); 54b82ccf041264d Jiri Slaby 2020-09-01 2056 if (!func_copy) 54b82ccf041264d Jiri Slaby 2020-09-01 2057 return -ENOMEM; 0d918baecc9263e Jiri Slaby 2020-08-14 2058 54b82ccf041264d Jiri Slaby 2020-09-01 2059 spin_lock_irqsave(&func_buf_lock, flags); 76f8a0386a60170 Jiri Slaby 2020-08-18 2060 len = strlcpy(func_copy, func_table[kb_func] ? : "", len); 54b82ccf041264d Jiri Slaby 2020-09-01 2061 spin_unlock_irqrestore(&func_buf_lock, flags); 54b82ccf041264d Jiri Slaby 2020-09-01 2062 54b82ccf041264d Jiri Slaby 2020-09-01 2063 ret = copy_to_user(user_kdgkb->kb_string, func_copy, len + 1) ? 54b82ccf041264d Jiri Slaby 2020-09-01 2064 -EFAULT : 0; 54b82ccf041264d Jiri Slaby 2020-09-01 2065 54b82ccf041264d Jiri Slaby 2020-09-01 @2066 kfree(func_copy); 54b82ccf041264d Jiri Slaby 2020-09-01 2067 54b82ccf041264d Jiri Slaby 2020-09-01 2068 return ret; 8092d18a17ab730 Jiri Slaby 2020-08-14 2069 } a959de21141d5d2 Jiri Slaby 2020-08-18 2070 case KDSKBSENT: { a959de21141d5d2 Jiri Slaby 2020-08-18 2071 char *kbs; a959de21141d5d2 Jiri Slaby 2020-08-18 2072 0d918baecc9263e Jiri Slaby 2020-08-14 2073 if (!perm) 0d918baecc9263e Jiri Slaby 2020-08-14 2074 return -EPERM; 0d918baecc9263e Jiri Slaby 2020-08-14 2075 0d918baecc9263e Jiri Slaby 2020-08-14 2076 kbs = strndup_user(user_kdgkb->kb_string, 0d918baecc9263e Jiri Slaby 2020-08-14 2077 sizeof(user_kdgkb->kb_string)); 0d918baecc9263e Jiri Slaby 2020-08-14 2078 if (IS_ERR(kbs)) 0d918baecc9263e Jiri Slaby 2020-08-14 2079 return PTR_ERR(kbs); 079c9534a96da9a Alan Cox 2012-02-28 2080 46ca3f735f345c9 Sergei Trofimovich 2019-03-10 2081 spin_lock_irqsave(&func_buf_lock, flags); a959de21141d5d2 Jiri Slaby 2020-08-18 2082 kbs = vt_kdskbsent(kbs, kb_func); 46ca3f735f345c9 Sergei Trofimovich 2019-03-10 2083 spin_unlock_irqrestore(&func_buf_lock, flags); a959de21141d5d2 Jiri Slaby 2020-08-18 2084 079c9534a96da9a Alan Cox 2012-02-28 2085 kfree(kbs); a959de21141d5d2 Jiri Slaby 2020-08-18 2086 a959de21141d5d2 Jiri Slaby 2020-08-18 2087 return 0; a959de21141d5d2 Jiri Slaby 2020-08-18 2088 } a959de21141d5d2 Jiri Slaby 2020-08-18 2089 } a959de21141d5d2 Jiri Slaby 2020-08-18 2090 a959de21141d5d2 Jiri Slaby 2020-08-18 2091 return 0; 079c9534a96da9a Alan Cox 2012-02-28 2092 } 079c9534a96da9a Alan Cox 2012-02-28 2093 :::::: The code at line 2066 was first introduced by commit :::::: 54b82ccf041264dfd324f62719a430483a823028 vt: keyboard, extend func_buf_lock to readers :::::: TO: Jiri Slaby <jslaby(a)suse.cz&gt; :::::: CC: Jiri Slaby <jslaby(a)suse.cz&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org