[dhowells-fs:fscache-iter 24/77] fs/fscache/cookie.c:417:9: sparse: sparse: context imbalance in '__fscache_use_cookie' - different lock contexts for basic block

[dhowells-fs:fscache-iter 24/77] fs/fscache/cookie.c:417:9: sparse: sparse: context imbalance in '__fscache_use_cookie' - different lock contexts for basic block

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
TO: David Howells <dhowells@redhat.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git fscache-iter
head:   b4bd0d0f8fce90046f12d2e6f674c0ba023a7419
commit: c96bc3c2cb1949c6e72d5674854338da99ea0e60 [24/77] fscache: Replace the object management state machine
:::::: branch date: 30 hours ago
:::::: commit date: 30 hours ago
config: i386-randconfig-s002-20210119 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.3-208-g46a52ca4-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit/?id=c96bc3c2cb1949c6e72d5674854338da99ea0e60
        git remote add dhowells-fs https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
        git fetch --no-tags dhowells-fs fscache-iter
        git checkout c96bc3c2cb1949c6e72d5674854338da99ea0e60
        # save the attached .config to linux build tree
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=i386 

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/fscache/cookie.c:417:9: sparse: sparse: context imbalance in '__fscache_use_cookie' - different lock contexts for basic block

vim +/__fscache_use_cookie +417 fs/fscache/cookie.c

ccc4fc3d11e91477 David Howells 2009-04-03  357  
94d30ae90a00cafe David Howells 2013-09-21  358  /*
c96bc3c2cb1949c6 David Howells 2020-02-06  359   * Start using the cookie for I/O.  This prevents the backing object from being
c96bc3c2cb1949c6 David Howells 2020-02-06  360   * reaped by VM pressure.
ccc4fc3d11e91477 David Howells 2009-04-03  361   */
c96bc3c2cb1949c6 David Howells 2020-02-06  362  void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify)
ccc4fc3d11e91477 David Howells 2009-04-03  363  {
c96bc3c2cb1949c6 David Howells 2020-02-06  364  	enum fscache_cookie_stage stage;
ccc4fc3d11e91477 David Howells 2009-04-03  365  
c96bc3c2cb1949c6 David Howells 2020-02-06  366  	_enter("c=%08x", cookie->debug_id);
ccc4fc3d11e91477 David Howells 2009-04-03  367  
c96bc3c2cb1949c6 David Howells 2020-02-06  368  	if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
c96bc3c2cb1949c6 David Howells 2020-02-06  369  		 "Trying to use relinquished cookie\n"))
c96bc3c2cb1949c6 David Howells 2020-02-06  370  		return;
ccc4fc3d11e91477 David Howells 2009-04-03  371  
c96bc3c2cb1949c6 David Howells 2020-02-06  372  	spin_lock(&cookie->lock);
ccc4fc3d11e91477 David Howells 2009-04-03  373  
c96bc3c2cb1949c6 David Howells 2020-02-06  374  	atomic_inc(&cookie->n_active);
ccc4fc3d11e91477 David Howells 2009-04-03  375  
c96bc3c2cb1949c6 David Howells 2020-02-06  376  again:
c96bc3c2cb1949c6 David Howells 2020-02-06  377  	stage = cookie->stage;
c96bc3c2cb1949c6 David Howells 2020-02-06  378  	switch (stage) {
c96bc3c2cb1949c6 David Howells 2020-02-06  379  	case FSCACHE_COOKIE_STAGE_QUIESCENT:
c96bc3c2cb1949c6 David Howells 2020-02-06  380  		cookie->stage = FSCACHE_COOKIE_STAGE_INITIALISING;
ccc4fc3d11e91477 David Howells 2009-04-03  381  
c96bc3c2cb1949c6 David Howells 2020-02-06  382  		/* The lookup job holds its own active increment */
c96bc3c2cb1949c6 David Howells 2020-02-06  383  		atomic_inc(&cookie->n_active);
c96bc3c2cb1949c6 David Howells 2020-02-06  384  		spin_unlock(&cookie->lock);
c96bc3c2cb1949c6 David Howells 2020-02-06  385  		wake_up_cookie_stage(cookie);
ccc4fc3d11e91477 David Howells 2009-04-03  386  
c96bc3c2cb1949c6 David Howells 2020-02-06  387  		fscache_dispatch(cookie, NULL, will_modify, fscache_lookup_object);
c96bc3c2cb1949c6 David Howells 2020-02-06  388  		break;
ccc4fc3d11e91477 David Howells 2009-04-03  389  
c96bc3c2cb1949c6 David Howells 2020-02-06  390  	case FSCACHE_COOKIE_STAGE_INITIALISING:
c96bc3c2cb1949c6 David Howells 2020-02-06  391  	case FSCACHE_COOKIE_STAGE_LOOKING_UP:
ccc4fc3d11e91477 David Howells 2009-04-03  392  		spin_unlock(&cookie->lock);
c96bc3c2cb1949c6 David Howells 2020-02-06  393  		wait_var_event(&cookie->stage, READ_ONCE(cookie->stage) != stage);
c96bc3c2cb1949c6 David Howells 2020-02-06  394  		spin_lock(&cookie->lock);
c96bc3c2cb1949c6 David Howells 2020-02-06  395  		goto again;
ccc4fc3d11e91477 David Howells 2009-04-03  396  
c96bc3c2cb1949c6 David Howells 2020-02-06  397  	case FSCACHE_COOKIE_STAGE_NO_DATA_YET:
c96bc3c2cb1949c6 David Howells 2020-02-06  398  	case FSCACHE_COOKIE_STAGE_ACTIVE:
c96bc3c2cb1949c6 David Howells 2020-02-06  399  	case FSCACHE_COOKIE_STAGE_INVALIDATING:
c96bc3c2cb1949c6 David Howells 2020-02-06  400  		// TODO: Handle will_modify
c96bc3c2cb1949c6 David Howells 2020-02-06  401  		spin_unlock(&cookie->lock);
c96bc3c2cb1949c6 David Howells 2020-02-06  402  		break;
ccc4fc3d11e91477 David Howells 2009-04-03  403  
c96bc3c2cb1949c6 David Howells 2020-02-06  404  	case FSCACHE_COOKIE_STAGE_FAILED:
c96bc3c2cb1949c6 David Howells 2020-02-06  405  	case FSCACHE_COOKIE_STAGE_WITHDRAWING:
ccc4fc3d11e91477 David Howells 2009-04-03  406  		spin_unlock(&cookie->lock);
c96bc3c2cb1949c6 David Howells 2020-02-06  407  		break;
ccc4fc3d11e91477 David Howells 2009-04-03  408  
c96bc3c2cb1949c6 David Howells 2020-02-06  409  	case FSCACHE_COOKIE_STAGE_INDEX:
c96bc3c2cb1949c6 David Howells 2020-02-06  410  	case FSCACHE_COOKIE_STAGE_DROPPED:
c96bc3c2cb1949c6 David Howells 2020-02-06  411  	case FSCACHE_COOKIE_STAGE_RELINQUISHING:
c96bc3c2cb1949c6 David Howells 2020-02-06  412  		spin_unlock(&cookie->lock);
c96bc3c2cb1949c6 David Howells 2020-02-06  413  		WARN(1, "Can't use cookie in stage %u\n", cookie->stage);
c96bc3c2cb1949c6 David Howells 2020-02-06  414  		break;
ccc4fc3d11e91477 David Howells 2009-04-03  415  	}
ccc4fc3d11e91477 David Howells 2009-04-03  416  
c96bc3c2cb1949c6 David Howells 2020-02-06 @417  	_leave("");
ccc4fc3d11e91477 David Howells 2009-04-03  418  }
c96bc3c2cb1949c6 David Howells 2020-02-06  419  EXPORT_SYMBOL(__fscache_use_cookie);
ccc4fc3d11e91477 David Howells 2009-04-03  420  

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

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