linux-kernel - mm/memcontrol.c:1058:29: warning: unused function 'memcg_kmem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <202111271029.EeYluWMG-lkp@intel.com>
Date:   Sat, 27 Nov 2021 10:43:14 +0800
From:   kernel test robot <lkp@...el.com>
To:     Muchun Song <songmuchun@...edance.com>
Cc:     llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
        linux-kernel@...r.kernel.org, Shakeel Butt <shakeelb@...gle.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linux Memory Management List <linux-mm@...ck.org>
Subject: mm/memcontrol.c:1058:29: warning: unused function 'memcg_kmem_bypass'

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   c5c17547b778975b3d83a73c8d84e8fb5ecf3ba5
commit: b4e0b68fbd9d1fd7e31cbe8adca3ad6cf556e2ee mm: memcontrol: use obj_cgroup APIs to charge kmem pages
date:   7 months ago
config: mips-randconfig-r022-20211122 (https://download.01.org/0day-ci/archive/20211127/202111271029.EeYluWMG-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c133fb321f7ca6083ce15b6aa5bf89de6600e649)
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 mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b4e0b68fbd9d1fd7e31cbe8adca3ad6cf556e2ee
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout b4e0b68fbd9d1fd7e31cbe8adca3ad6cf556e2ee
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash

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

All warnings (new ones prefixed by >>):

>> mm/memcontrol.c:1058:29: warning: unused function 'memcg_kmem_bypass'
   static __always_inline bool memcg_kmem_bypass(void)
   ^
   fatal error: error in backend: Nested variants found in inline asm string: ' .set push
   .set noat
   .set push
   .set arch=r4000
   .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif
   1: ll $0, $2 # __cmpxchg_asm
   bne $0, ${3:z}, 2f
   .set pop
   move $$1, ${4:z}
   .set arch=r4000
   sc $$1, $1
   beqz $$1, 1b
   .set pop
   2: .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif
   '
   clang-14: error: clang frontend command failed with exit code 70 (use -v to see invocation)
   clang version 14.0.0 (git://gitmirror/llvm_project 5162b558d8c0b542e752b037e72a69d5fd51eb1e)
   Target: mips-unknown-linux
   Thread model: posix
   InstalledDir: /opt/cross/clang-5162b558d8/bin
   clang-14: note: diagnostic msg:
   Makefile arch block certs crypto drivers fs include init ipc kernel lib mm net nr_bisected scripts security sound source usr virt


vim +/memcg_kmem_bypass +1058 mm/memcontrol.c

279c3393e2c1133 Roman Gushchin 2020-10-17  1057  
4127c6504f25c4f Roman Gushchin 2020-10-17 @1058  static __always_inline bool memcg_kmem_bypass(void)
4127c6504f25c4f Roman Gushchin 2020-10-17  1059  {
4127c6504f25c4f Roman Gushchin 2020-10-17  1060  	/* Allow remote memcg charging from any context. */
4127c6504f25c4f Roman Gushchin 2020-10-17  1061  	if (unlikely(active_memcg()))
4127c6504f25c4f Roman Gushchin 2020-10-17  1062  		return false;
4127c6504f25c4f Roman Gushchin 2020-10-17  1063  
4127c6504f25c4f Roman Gushchin 2020-10-17  1064  	/* Memcg to charge can't be determined. */
4127c6504f25c4f Roman Gushchin 2020-10-17  1065  	if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
4127c6504f25c4f Roman Gushchin 2020-10-17  1066  		return true;
4127c6504f25c4f Roman Gushchin 2020-10-17  1067  
4127c6504f25c4f Roman Gushchin 2020-10-17  1068  	return false;
4127c6504f25c4f Roman Gushchin 2020-10-17  1069  }
4127c6504f25c4f Roman Gushchin 2020-10-17  1070  

:::::: The code at line 1058 was first introduced by commit
:::::: 4127c6504f25c4fcff52dc996efda2ef859dd661 mm: kmem: enable kernel memcg accounting from interrupt contexts

:::::: TO: Roman Gushchin <guro@...com>
:::::: CC: Linus Torvalds <torvalds@...ux-foundation.org>

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