Re: [PATCH v4] mm: Uninline copy_overflow()

[Chen, Rong A <rong.a.chen@intel.com>]

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Hi Christophe,

On 2/14/2022 2:58 AM, Christophe Leroy wrote:
> 
> 
> Le 12/02/2022 à 19:17, kernel test robot a écrit :
>> Hi Christophe,
>>
>> I love your patch! Yet something to improve:
>>
>> [auto build test ERROR on linux/master]
>> [also build test ERROR on linus/master v5.17-rc3]
>> [cannot apply to hnaz-mm/master next-20220211]
>> [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/Christophe-Leroy/mm-Uninline-copy_overflow/20220212-155040
>> base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2c271fe77d52a0555161926c232cd5bc07178b39
>> config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20220213/202202130121.dZLDqfpe-lkp(a)intel.com/config)
>> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
>> reproduce (this is a W=1 build):
>>           # https://github.com/0day-ci/linux/commit/cf4474ac62f0332bd9d39f9dd74dbb5afce9a7a4
>>           git remote add linux-review https://github.com/0day-ci/linux
>>           git fetch --no-tags linux-review Christophe-Leroy/mm-Uninline-copy_overflow/20220212-155040
>>           git checkout cf4474ac62f0332bd9d39f9dd74dbb5afce9a7a4
>>           # save the config file to linux build tree
>>           mkdir build_dir
>>           make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>>
>> All errors (new ones prefixed by >>):
>>
>>      In file included from arch/x86/include/asm/preempt.h:7,
>>                       from include/linux/preempt.h:78,
>>                       from include/linux/percpu.h:6,
>>                       from include/linux/context_tracking_state.h:5,
>>                       from include/linux/hardirq.h:5,
>>                       from drivers/net/ethernet/mellanox/mlx4/cq.c:37:
>>      In function 'check_copy_size',
>>          inlined from 'copy_to_user' at include/linux/uaccess.h:199:6,
>>          inlined from 'mlx4_init_user_cqes' at drivers/net/ethernet/mellanox/mlx4/cq.c:317:9,
>>          inlined from 'mlx4_cq_alloc' at drivers/net/ethernet/mellanox/mlx4/cq.c:394:10:
>>>> include/linux/thread_info.h:228:4: error: call to '__bad_copy_from' declared with attribute error: copy source size is too small
>>        228 |    __bad_copy_from();
>>            |    ^~~~~~~~~~~~~~~~~
>>
> 
> This looks like a bug in GCC 9.x
> 
> You get the exact same result without my patch when unselecting CONFIG_BUG
> 
> You don't get the problem with gcc 8.5
> You don't get the problem with gcc 10.3
> 
> My patch itself doesn't explain getting this error.

Thanks for the detailed explanation, we'll add the error to ignore list.

Best Regards,
Rong Chen