Re: [PATCH -mm 1/1] signal: simplify set_user_sigmask/restore_user_sigmask

From: kbuild test robot
Date: Wed Jun 05 2019 - 20:19:38 EST


Hi Oleg,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mmotm/master]

url: https://github.com/0day-ci/linux/commits/Oleg-Nesterov/signal-simplify-set_user_sigmask-restore_user_sigmask/20190606-062512
base: git://git.cmpxchg.org/linux-mmotm.git master
config: m68k-allyesconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 7.4.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.4.0 make.cross ARCH=m68k

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

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 arch/m68k/include/asm/uaccess.h:5:0,
from include/linux/uaccess.h:11,
from include/asm-generic/termios.h:6,
from ./arch/m68k/include/generated/uapi/asm/termios.h:1,
from include/uapi/linux/termios.h:6,
from include/linux/tty.h:7,
from kernel/signal.c:26:
kernel/signal.c: In function 'set_user_sigmask':
>> arch/m68k/include/asm/uaccess_mm.h:191:2: warning: 'kmask' may be used uninitialized in this function [-Wmaybe-uninitialized]
asm volatile ("\n" \
^~~
kernel/signal.c:2960:12: note: 'kmask' was declared here
sigset_t *kmask;
^~~~~

vim +/kmask +191 arch/m68k/include/asm/uaccess_mm.h

7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 189
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 190 #define ____constant_copy_from_user_asm(res, to, from, tmp, n1, n2, n3, s1, s2, s3)\
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 @191 asm volatile ("\n" \
e08d703c arch/m68k/include/asm/uaccess_mm.h Greg Ungerer 2011-10-14 192 "1: "MOVES"."#s1" (%2)+,%3\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 193 " move."#s1" %3,(%1)+\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 194 " .ifnc \""#s2"\",\"\"\n" \
e08d703c arch/m68k/include/asm/uaccess_mm.h Greg Ungerer 2011-10-14 195 "2: "MOVES"."#s2" (%2)+,%3\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 196 " move."#s2" %3,(%1)+\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 197 " .ifnc \""#s3"\",\"\"\n" \
e08d703c arch/m68k/include/asm/uaccess_mm.h Greg Ungerer 2011-10-14 198 "3: "MOVES"."#s3" (%2)+,%3\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 199 " move."#s3" %3,(%1)+\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 200 " .endif\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 201 " .endif\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 202 "4:\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 203 " .section __ex_table,\"a\"\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 204 " .align 4\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 205 " .long 1b,10f\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 206 " .ifnc \""#s2"\",\"\"\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 207 " .long 2b,20f\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 208 " .ifnc \""#s3"\",\"\"\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 209 " .long 3b,30f\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 210 " .endif\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 211 " .endif\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 212 " .previous\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 213 "\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 214 " .section .fixup,\"ax\"\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 215 " .even\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 216 "10: addq.l #"#n1",%0\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 217 " .ifnc \""#s2"\",\"\"\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 218 "20: addq.l #"#n2",%0\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 219 " .ifnc \""#s3"\",\"\"\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 220 "30: addq.l #"#n3",%0\n" \
7cefa5a0 arch/m68k/include/asm/uaccess_mm.h Al Viro 2017-03-20 221 " .endif\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 222 " .endif\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 223 " jra 4b\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 224 " .previous\n" \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 225 : "+d" (res), "+&a" (to), "+a" (from), "=&d" (tmp) \
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 226 : : "memory")
53617825 include/asm-m68k/uaccess.h Roman Zippel 2006-06-25 227

:::::: The code at line 191 was first introduced by commit
:::::: 53617825ccf3ff8a71e6efcf3dcf58885ed6f3e5 [PATCH] m68k: fix uaccess.h for gcc-3.x

:::::: TO: Roman Zippel <zippel@xxxxxxxxxxxxxx>
:::::: CC: Linus Torvalds <torvalds@xxxxxxxxxxx>

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