linux-kernel - Re: [PATCH v2 4/4] coresight: etm3x: Don't trace PID for non-root PID namespace

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Message-ID: <20211214044628.GB1884193@leoy-ThinkPad-X240s>
Date:   Tue, 14 Dec 2021 12:46:28 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     kernel test robot <lkp@...el.com>
Cc:     Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, llvm@...ts.linux.dev,
        kbuild-all@...ts.01.org
Subject: Re: [PATCH v2 4/4] coresight: etm3x: Don't trace PID for non-root
 PID namespace

Hi,

On Tue, Dec 14, 2021 at 03:16:42AM +0800, kernel test robot wrote:
> Hi Leo,
> 
> I love your patch! Yet something to improve:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v5.16-rc5]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Leo-Yan/coresight-etm-Correct-PID-tracing-for-non-root-namespace/20211213-201632
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2585cf9dfaaddf00b069673f27bb3f8530e2039c
> config: arm-buildonly-randconfig-r003-20211213 (https://download.01.org/0day-ci/archive/20211214/202112140344.viPmOWp6-lkp@intel.com/config)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project b6a2ddb6c8ac29412b1361810972e15221fa021c)
> 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://github.com/0day-ci/linux/commit/81d5f47788c40d34c8159d64d4505eb485254e8f
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Leo-Yan/coresight-etm-Correct-PID-tracing-for-non-root-namespace/20211213-201632
>         git checkout 81d5f47788c40d34c8159d64d4505eb485254e8f
>         # 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=arm SHELL=/bin/bash drivers/hwtracing/coresight/
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@...el.com>
> 
> All errors (new ones prefixed by >>):
> 
> >> drivers/hwtracing/coresight/coresight-etm3x-core.c:344:7: error: implicit declaration of function 'task_is_in_init_pid_ns' [-Werror,-Wimplicit-function-declaration]
>            if (!task_is_in_init_pid_ns(current))
>                 ^
>    1 error generated.
> 
> 
> vim +/task_is_in_init_pid_ns +344 drivers/hwtracing/coresight/coresight-etm3x-core.c
> 
>    301	
>    302	#define ETM3X_SUPPORTED_OPTIONS (ETMCR_CYC_ACC | \
>    303					 ETMCR_TIMESTAMP_EN | \
>    304					 ETMCR_RETURN_STACK)
>    305	
>    306	static int etm_parse_event_config(struct etm_drvdata *drvdata,
>    307					  struct perf_event *event)
>    308	{
>    309		struct etm_config *config = &drvdata->config;
>    310		struct perf_event_attr *attr = &event->attr;
>    311	
>    312		if (!attr)
>    313			return -EINVAL;
>    314	
>    315		/* Clear configuration from previous run */
>    316		memset(config, 0, sizeof(struct etm_config));
>    317	
>    318		if (attr->exclude_kernel)
>    319			config->mode = ETM_MODE_EXCL_KERN;
>    320	
>    321		if (attr->exclude_user)
>    322			config->mode = ETM_MODE_EXCL_USER;
>    323	
>    324		/* Always start from the default config */
>    325		etm_set_default(config);
>    326	
>    327		/*
>    328		 * By default the tracers are configured to trace the whole address
>    329		 * range.  Narrow the field only if requested by user space.
>    330		 */
>    331		if (config->mode)
>    332			etm_config_trace_mode(config);
>    333	
>    334		/*
>    335		 * At this time only cycle accurate, return stack  and timestamp
>    336		 * options are available.
>    337		 */
>    338		if (attr->config & ~ETM3X_SUPPORTED_OPTIONS)
>    339			return -EINVAL;
>    340	
>    341		config->ctrl = attr->config;
>    342	
>    343		/* Don't trace contextID when runs in non-root PID namespace */
>  > 344		if (!task_is_in_init_pid_ns(current))

This patchset is based on another patchset [1], as described on the
cover letter patch.  This is why here reports for building failure.

To avoid the false positive reporting, if any better practice I can
follow up to resolve the dependency between two patchsets, please let
me know and I will do in next time.

Thanks,
Leo

[1] https://lore.kernel.org/lkml/20211208083320.472503-1-leo.yan@linaro.org/

>    345			config->ctrl &= ~ETMCR_CTXID_SIZE;
>    346	
>    347		/*
>    348		 * Possible to have cores with PTM (supports ret stack) and ETM
>    349		 * (never has ret stack) on the same SoC. So if we have a request
>    350		 * for return stack that can't be honoured on this core then
>    351		 * clear the bit - trace will still continue normally
>    352		 */
>    353		if ((config->ctrl & ETMCR_RETURN_STACK) &&
>    354		    !(drvdata->etmccer & ETMCCER_RETSTACK))
>    355			config->ctrl &= ~ETMCR_RETURN_STACK;
>    356	
>    357		return 0;
>    358	}
>    359	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org