linux-kernel - Re: [PATCH 2/2] kobject: wait until kobject is cleaned up before freeing module

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Date:   Fri, 5 Nov 2021 22:54:36 +0800
From:   Ming Lei <ming.lei@...hat.com>
To:     kernel test robot <lkp@...el.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        kbuild-all@...ts.01.org, Petr Mladek <pmladek@...e.com>,
        linux-kernel@...r.kernel.org, Luis Chamberlain <mcgrof@...nel.org>,
        Joe Lawrence <joe.lawrence@...hat.com>
Subject: Re: [PATCH 2/2] kobject: wait until kobject is cleaned up before
 freeing module

On Fri, Nov 05, 2021 at 10:10:07PM +0800, kernel test robot wrote:
> Hi Ming,
> 
> Thank you for the patch! Yet something to improve:
> 
> [auto build test ERROR on driver-core/driver-core-testing]
> [also build test ERROR on v5.15 next-20211105]
> [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/Ming-Lei/kobject-avoid-to-cleanup-kobject-after-module-is-unloaded/20211105-144026
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git 27e0bcd02990f7291adb0f111e300f06c495d509
> config: mips-buildonly-randconfig-r003-20211105 (attached as .config)
> compiler: mipsel-linux-gcc (GCC) 11.2.0
> 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
>         # https://github.com/0day-ci/linux/commit/4a9e015dd3d3e39d5723ea46579ba21f5394806a
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Ming-Lei/kobject-avoid-to-cleanup-kobject-after-module-is-unloaded/20211105-144026
>         git checkout 4a9e015dd3d3e39d5723ea46579ba21f5394806a
>         # save the attached .config to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross 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 errors (new ones prefixed by >>):
> 
>    lib/kobject.c: In function 'kobj_module_callback':
> >> lib/kobject.c:741:20: error: 'MODULE_STATE_GOING' undeclared (first use in this function)
>      741 |         if (val != MODULE_STATE_GOING)
>          |                    ^~~~~~~~~~~~~~~~~~
>    lib/kobject.c:741:20: note: each undeclared identifier is reported only once for each function it appears in

Hello,

Thanks for the report!

This must be triggered when CONFIG_MODULES is off, and the following patch
should kill the failure:


diff --git a/lib/kobject.c b/lib/kobject.c
index f5fd6017d8ce..c054dca0001a 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -738,8 +738,10 @@ static int kobj_module_callback(struct notifier_block *nb,
 {
 	LIST_HEAD(pending);
 
+#ifdef CONFIG_MODULES
 	if (val != MODULE_STATE_GOING)
 		return NOTIFY_DONE;
+#endif
 
 	spin_lock_irq(&kobj_cleanup_lock);
 	list_splice_init(&kobj_cleanup_list, &pending);


Thanks,
Ming