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* fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast
@ 2020-08-07 12:08 kernel test robot
  2020-08-07 14:48 ` Gao Xiang
  0 siblings, 1 reply; 3+ messages in thread
From: kernel test robot @ 2020-08-07 12:08 UTC (permalink / raw)
  To: Gao Xiang; +Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman

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Hi Gao,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   86cfccb66937dd6cbf26ed619958b9e587e6a115
commit: 47e4937a4a7ca4184fd282791dfee76c6799966a erofs: move erofs out of staging
date:   12 months ago
config: s390-randconfig-s032-20200807 (attached as .config)
compiler: s390-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.2-118-ge1578773-dirty
        git checkout 47e4937a4a7ca4184fd282791dfee76c6799966a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)

>> fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast
   fs/erofs/zdata.c:282:22: sparse: sparse: non size-preserving integer to pointer cast
   fs/erofs/zdata.c:1094:24: sparse: sparse: non size-preserving integer to pointer cast

vim +198 fs/erofs/zdata.c

3883a79abd0227 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  162  
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  163  static void preload_compressed_pages(struct z_erofs_collector *clt,
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  164  				     struct address_space *mc,
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  165  				     enum z_erofs_cache_alloctype type,
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  166  				     struct list_head *pagepool)
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  167  {
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  168  	const struct z_erofs_pcluster *pcl = clt->pcl;
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  169  	const unsigned int clusterpages = BIT(pcl->clusterbits);
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  170  	struct page **pages = clt->compressedpages;
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  171  	pgoff_t index = pcl->obj.index + (pages - pcl->compressed_pages);
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  172  	bool standalone = true;
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  173  
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  174  	if (clt->mode < COLLECT_PRIMARY_FOLLOWED)
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  175  		return;
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  176  
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  177  	for (; pages < pcl->compressed_pages + clusterpages; ++pages) {
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  178  		struct page *page;
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  179  		compressed_page_t t;
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  180  
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  181  		/* the compressed page was loaded before */
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  182  		if (READ_ONCE(*pages))
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  183  			continue;
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  184  
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  185  		page = find_get_page(mc, index);
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  186  
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  187  		if (page) {
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  188  			t = tag_compressed_page_justfound(page);
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  189  		} else if (type == DELAYEDALLOC) {
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  190  			t = tagptr_init(compressed_page_t, PAGE_UNALLOCATED);
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  191  		} else {	/* DONTALLOC */
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  192  			if (standalone)
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  193  				clt->compressedpages = pages;
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  194  			standalone = false;
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  195  			continue;
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  196  		}
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  197  
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31 @198  		if (!cmpxchg_relaxed(pages, NULL, tagptr_cast_ptr(t)))
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  199  			continue;
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  200  
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  201  		if (page)
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  202  			put_page(page);
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  203  	}
92e6efd566c4a1 drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-12-08  204  
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  205  	if (standalone)		/* downgrade to PRIMARY_FOLLOWED_NOINPLACE */
97e86a858bc360 drivers/staging/erofs/zdata.c     Gao Xiang 2019-07-31  206  		clt->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  207  }
105d4ad857dcbf drivers/staging/erofs/unzip_vle.c Gao Xiang 2018-07-26  208  

:::::: The code at line 198 was first introduced by commit
:::::: 97e86a858bc360c9cded74ce9a06595d40f7ad81 staging: erofs: tidy up decompression frontend

:::::: TO: Gao Xiang <gaoxiang25@huawei.com>
:::::: CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast
  2020-08-07 12:08 fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast kernel test robot
@ 2020-08-07 14:48 ` Gao Xiang
  2020-08-07 15:05   ` Luc Van Oostenryck
  0 siblings, 1 reply; 3+ messages in thread
From: Gao Xiang @ 2020-08-07 14:48 UTC (permalink / raw)
  To: kernel test robot; +Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman

Hi,

On Fri, Aug 07, 2020 at 08:08:10PM +0800, kernel test robot wrote:
> Hi Gao,
> 
> First bad commit (maybe != root cause):
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   86cfccb66937dd6cbf26ed619958b9e587e6a115
> commit: 47e4937a4a7ca4184fd282791dfee76c6799966a erofs: move erofs out of staging
> date:   12 months ago
> config: s390-randconfig-s032-20200807 (attached as .config)
> compiler: s390-linux-gcc (GCC) 9.3.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # apt-get install sparse
>         # sparse version: v0.6.2-118-ge1578773-dirty
>         git checkout 47e4937a4a7ca4184fd282791dfee76c6799966a
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=s390 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> 
> sparse warnings: (new ones prefixed by >>)
> 
> >> fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast
>    fs/erofs/zdata.c:282:22: sparse: sparse: non size-preserving integer to pointer cast
>    fs/erofs/zdata.c:1094:24: sparse: sparse: non size-preserving integer to pointer cast

I don't think these are valid warnings.

All these three lines are using cmpxchg struct page * (which is equivalent to unsigned long
in these cmpxchg macros) and nothing special at all in my opinion (Especially the last two
lines).

+198	if (!cmpxchg_relaxed(pages, NULL, tagptr_cast_ptr(t)))
+282	if (!cmpxchg(clt->compressedpages++, NULL, page))
+1094	if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) {

btw, recently sparse warnings quite confuse me (p.s. they're all on alpha/s390/sparc archs and relate
to cmpxchg/xchg by accident), I have no idea what happened with sparse.

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast
  2020-08-07 14:48 ` Gao Xiang
@ 2020-08-07 15:05   ` Luc Van Oostenryck
  0 siblings, 0 replies; 3+ messages in thread
From: Luc Van Oostenryck @ 2020-08-07 15:05 UTC (permalink / raw)
  To: Gao Xiang; +Cc: kernel test robot, kbuild-all, linux-kernel, Greg Kroah-Hartman

On Fri, Aug 07, 2020 at 10:48:12PM +0800, Gao Xiang wrote:
> On Fri, Aug 07, 2020 at 08:08:10PM +0800, kernel test robot wrote:
> > sparse warnings: (new ones prefixed by >>)
> > 
> > >> fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast
> >    fs/erofs/zdata.c:282:22: sparse: sparse: non size-preserving integer to pointer cast
> >    fs/erofs/zdata.c:1094:24: sparse: sparse: non size-preserving integer to pointer cast
> 
> I don't think these are valid warnings.

Indeed, they're not.
 
> All these three lines are using cmpxchg struct page * (which is equivalent to unsigned long
> in these cmpxchg macros) and nothing special at all in my opinion (Especially the last two
> lines).

What is special is that s390 use __sync_val_compare_and_swap() to implement
cmpxchg(). This builtin has a return type which depends on its arguments
while sparse was always using 'int' as the return type.

A patch is on the way.

Regards,
-- Luc Van Oostenryck

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2020-08-07 15:05 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-07 12:08 fs/erofs/zdata.c:198:22: sparse: sparse: non size-preserving integer to pointer cast kernel test robot
2020-08-07 14:48 ` Gao Xiang
2020-08-07 15:05   ` Luc Van Oostenryck

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