[arm-integrator:kasan 2/7] arch/arm/kernel/setup.c:1082:6: warning: variable 'atags_vaddr' is used uninitialized whenever 'if' condition is false

[arm-integrator:kasan 2/7] arch/arm/kernel/setup.c:1082:6: warning: variable 'atags_vaddr' is used uninitialized whenever 'if' condition is false

[kernel test robot]

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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git kasan
head:   5f59c4b4d210bba804bdce643f9c067246d6e244
commit: 37d8ebb48491dab3fe0d926693f6b27ddc32eebd [2/7] ARM: move device tree mapping out of linear region
config: arm-randconfig-r003-20201006 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 1127662c6dc2a276839c75a42238b11a3ad00f32)
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
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git/commit/?id=37d8ebb48491dab3fe0d926693f6b27ddc32eebd
        git remote add arm-integrator https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git
        git fetch --no-tags arm-integrator kasan
        git checkout 37d8ebb48491dab3fe0d926693f6b27ddc32eebd
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> arch/arm/kernel/setup.c:1082:6: warning: variable 'atags_vaddr' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (__atags_pointer)
               ^~~~~~~~~~~~~~~
   arch/arm/kernel/setup.c:1086:6: note: uninitialized use occurs here
           if (atags_vaddr) {
               ^~~~~~~~~~~
   arch/arm/kernel/setup.c:1082:2: note: remove the 'if' if its condition is always true
           if (__atags_pointer)
           ^~~~~~~~~~~~~~~~~~~~
   arch/arm/kernel/setup.c:1080:19: note: initialize the variable 'atags_vaddr' to silence this warning
           void *atags_vaddr;
                            ^
                             = NULL
   1 warning generated.

vim +1082 arch/arm/kernel/setup.c

4588c34daabb5ae Dave Martin    2012-02-17  1076  
6291319d4864848 Grant Likely   2011-04-28  1077  void __init setup_arch(char **cmdline_p)
6291319d4864848 Grant Likely   2011-04-28  1078  {
6f508bba1738a1c Ard Biesheuvel 2020-10-06  1079  	const struct machine_desc *mdesc = NULL;
37d8ebb48491dab Ard Biesheuvel 2020-10-06  1080  	void *atags_vaddr;
6f508bba1738a1c Ard Biesheuvel 2020-10-06  1081  
6f508bba1738a1c Ard Biesheuvel 2020-10-06 @1082  	if (__atags_pointer)
37d8ebb48491dab Ard Biesheuvel 2020-10-06  1083  		atags_vaddr = FDT_VIRT_ADDR(__atags_pointer);
6291319d4864848 Grant Likely   2011-04-28  1084  
6291319d4864848 Grant Likely   2011-04-28  1085  	setup_processor();
37d8ebb48491dab Ard Biesheuvel 2020-10-06  1086  	if (atags_vaddr) {
6f508bba1738a1c Ard Biesheuvel 2020-10-06  1087  		mdesc = setup_machine_fdt(atags_vaddr);
37d8ebb48491dab Ard Biesheuvel 2020-10-06  1088  		if (mdesc)
37d8ebb48491dab Ard Biesheuvel 2020-10-06  1089  			memblock_reserve(__atags_pointer,
37d8ebb48491dab Ard Biesheuvel 2020-10-06  1090  					 fdt_totalsize(atags_vaddr));
37d8ebb48491dab Ard Biesheuvel 2020-10-06  1091  	}
93c02ab40ae6e06 Grant Likely   2011-04-28  1092  	if (!mdesc)
6f508bba1738a1c Ard Biesheuvel 2020-10-06  1093  		mdesc = setup_machine_tags(atags_vaddr, __machine_arch_type);
99cf8f903148347 Russell King   2017-09-21  1094  	if (!mdesc) {
99cf8f903148347 Russell King   2017-09-21  1095  		early_print("\nError: invalid dtb and unrecognized/unsupported machine ID\n");
99cf8f903148347 Russell King   2017-09-21  1096  		early_print("  r1=0x%08x, r2=0x%08x\n", __machine_arch_type,
99cf8f903148347 Russell King   2017-09-21  1097  			    __atags_pointer);
99cf8f903148347 Russell King   2017-09-21  1098  		if (__atags_pointer)
6f508bba1738a1c Ard Biesheuvel 2020-10-06  1099  			early_print("  r2[]=%*ph\n", 16, atags_vaddr);
99cf8f903148347 Russell King   2017-09-21  1100  		dump_machine_table();
99cf8f903148347 Russell King   2017-09-21  1101  	}
99cf8f903148347 Russell King   2017-09-21  1102  
6291319d4864848 Grant Likely   2011-04-28  1103  	machine_desc = mdesc;
6291319d4864848 Grant Likely   2011-04-28  1104  	machine_name = mdesc->name;
719c9d1489bad6f Russell King   2014-10-28  1105  	dump_stack_set_arch_desc("%s", mdesc->name);
6291319d4864848 Grant Likely   2011-04-28  1106  
16d6d5b00ee7530 Robin Holt     2013-07-08  1107  	if (mdesc->reboot_mode != REBOOT_HARD)
16d6d5b00ee7530 Robin Holt     2013-07-08  1108  		reboot_mode = mdesc->reboot_mode;
6291319d4864848 Grant Likely   2011-04-28  1109  
37efe6427dd50e8 Russell King   2008-12-01  1110  	init_mm.start_code = (unsigned long) _text;
37efe6427dd50e8 Russell King   2008-12-01  1111  	init_mm.end_code   = (unsigned long) _etext;
37efe6427dd50e8 Russell King   2008-12-01  1112  	init_mm.end_data   = (unsigned long) _edata;
37efe6427dd50e8 Russell King   2008-12-01  1113  	init_mm.brk	   = (unsigned long) _end;
^1da177e4c3f415 Linus Torvalds 2005-04-16  1114  
48ab7e09e0a7c00 Jeremy Kerr    2010-01-27  1115  	/* populate cmd_line too for later use, preserving boot_command_line */
48ab7e09e0a7c00 Jeremy Kerr    2010-01-27  1116  	strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
48ab7e09e0a7c00 Jeremy Kerr    2010-01-27  1117  	*cmdline_p = cmd_line;
2b0d8c251b8876d Jeremy Kerr    2010-01-11  1118  
a5f4c561b3b19a9 Stefan Agner   2015-08-13  1119  	early_fixmap_init();
2937367b8a4b0d4 Ard Biesheuvel 2015-09-01  1120  	early_ioremap_init();
a5f4c561b3b19a9 Stefan Agner   2015-08-13  1121  
2b0d8c251b8876d Jeremy Kerr    2010-01-11  1122  	parse_early_param();
2b0d8c251b8876d Jeremy Kerr    2010-01-11  1123  

:::::: The code at line 1082 was first introduced by commit
:::::: 6f508bba1738a1c09850787a543b1df44ce92916 ARM: centralize phys-to-virt conversion of DT/ATAGS address

:::::: TO: Ard Biesheuvel <ardb@kernel.org>
:::::: CC: Linus Walleij <linus.walleij@linaro.org>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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