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Date:   Fri, 9 Jun 2023 17:12:28 +0800
From:   kernel test robot <lkp@intel.com>
To:     Vincent Whitchurch <vincent.whitchurch@axis.com>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev,
        Linux Memory Management List <linux-mm@kvack.org>,
        linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel@axis.com, Vincent Whitchurch <vincent.whitchurch@axis.com>
Subject: Re: [PATCH] watchdog/mm: Allow dumping memory info in pretimeout
Message-ID: <202306091716.pcrXYphk-lkp@intel.com>
References: <20230608-pretimeout-oom-v1-1-542cc91062d7@axis.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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In-Reply-To: <20230608-pretimeout-oom-v1-1-542cc91062d7@axis.com>
Precedence: bulk

Hi Vincent,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 9561de3a55bed6bdd44a12820ba81ec416e705a7]

url:    https://github.com/intel-lab-lkp/linux/commits/Vincent-Whitchurch/watchdog-mm-Allow-dumping-memory-info-in-pretimeout/20230609-144807
base:   9561de3a55bed6bdd44a12820ba81ec416e705a7
patch link:    https://lore.kernel.org/r/20230608-pretimeout-oom-v1-1-542cc91062d7%40axis.com
patch subject: [PATCH] watchdog/mm: Allow dumping memory info in pretimeout
config: hexagon-buildonly-randconfig-r001-20230608 (https://download.01.org/0day-ci/archive/20230609/202306091716.pcrXYphk-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build):
        mkdir -p ~/bin
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout 9561de3a55bed6bdd44a12820ba81ec416e705a7
        b4 shazam https://lore.kernel.org/r/20230608-pretimeout-oom-v1-1-542cc91062d7@axis.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash

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/202306091716.pcrXYphk-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from mm/oom_kill.c:30:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:9:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from mm/oom_kill.c:30:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:9:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from mm/oom_kill.c:30:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:13:
   In file included from include/linux/cgroup.h:26:
   In file included from include/linux/kernel_stat.h:9:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:334:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
>> mm/oom_kill.c:156:21: warning: no previous prototype for function 'find_trylock_task_mm' [-Wmissing-prototypes]
     156 | struct task_struct *find_trylock_task_mm(struct task_struct *p)
         |                     ^
   mm/oom_kill.c:156:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     156 | struct task_struct *find_trylock_task_mm(struct task_struct *p)
         | ^
         | static 
   7 warnings generated.


vim +/find_trylock_task_mm +156 mm/oom_kill.c

   151	
   152	/*
   153	 * Identical to the above, except that we avoid tasks which we can't lock, to
   154	 * avoid deadlocks when called from an interrupt handler.
   155	 */
 > 156	struct task_struct *find_trylock_task_mm(struct task_struct *p)
   157	{
   158		struct task_struct *t;
   159	
   160		rcu_read_lock();
   161	
   162		for_each_thread(p, t) {
   163			if (!task_trylock(t))
   164				continue;
   165			if (likely(t->mm))
   166				goto found;
   167			task_unlock(t);
   168		}
   169		t = NULL;
   170	found:
   171		rcu_read_unlock();
   172	
   173		return t;
   174	}
   175	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki