Hi Sven,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.10-rc4 next-20170120]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Sven-Schmidt/Update-LZ4-compressor-module/20170121-231418
config: i386-randconfig-r0-201703 (attached as .config)
compiler: gcc-5 (Debian 5.4.1-2) 5.4.1 20160904
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

Note: the linux-review/Sven-Schmidt/Update-LZ4-compressor-module/20170121-231418 HEAD 0472409e2a1c442b51502961aa6d83b866218953 builds fine.
      It only hurts bisectibility.

All errors (new ones prefixed by >>):

   fs/pstore/platform.c: In function 'allocate_lz4':

quoted

fs/pstore/platform.c:369:20: error: implicit declaration of function 'lz4_compressbound' [-Werror=implicit-function-declaration]

     big_oops_buf_sz = lz4_compressbound(psinfo->bufsize);
                       ^
   cc1: some warnings being treated as errors

vim +/lz4_compressbound +369 fs/pstore/platform.c

8cfc8ddc Geliang Tang 2016-02-18  363  
8cfc8ddc Geliang Tang 2016-02-18  364  	return outlen;
8cfc8ddc Geliang Tang 2016-02-18  365  }
8cfc8ddc Geliang Tang 2016-02-18  366  
8cfc8ddc Geliang Tang 2016-02-18  367  static void allocate_lz4(void)
8cfc8ddc Geliang Tang 2016-02-18  368  {
8cfc8ddc Geliang Tang 2016-02-18 @369  	big_oops_buf_sz = lz4_compressbound(psinfo->bufsize);
8cfc8ddc Geliang Tang 2016-02-18  370  	big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
8cfc8ddc Geliang Tang 2016-02-18  371  	if (big_oops_buf) {
8cfc8ddc Geliang Tang 2016-02-18  372  		workspace = kmalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);

:::::: The code at line 369 was first introduced by commit
:::::: 8cfc8ddc99df9509a46043b14af81f5c6a223eab pstore: add lzo/lz4 compression support

:::::: TO: Geliang Tang [off-list ref]
:::::: CC: Kees Cook [off-list ref]

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