Re: [PATCH v14 074/138] mm/writeback: Add folio_clear_dirty_for_io()

[kernel test robot <lkp@intel.com>]

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CC: kbuild-all(a)lists.01.org
In-Reply-To: <20210715033704.692967-75-willy@infradead.org>
References: <20210715033704.692967-75-willy@infradead.org>
TO: "Matthew Wilcox (Oracle)" <willy@infradead.org>
TO: linux-kernel(a)vger.kernel.org
CC: "Matthew Wilcox (Oracle)" <willy@infradead.org>
CC: linux-mm(a)kvack.org
CC: linux-fsdevel(a)vger.kernel.org
CC: Christoph Hellwig <hch@lst.de>

Hi "Matthew,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to hnaz-linux-mm/master xfs-linux/for-next tip/perf/core v5.14-rc1 next-20210716]
[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/Matthew-Wilcox-Oracle/Memory-folios/20210715-133101
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8096acd7442e613fad0354fc8dfdb2003cceea0b
:::::: branch date: 3 days ago
:::::: commit date: 3 days ago
config: x86_64-rhel-8.3-kselftests (attached as .config)
compiler: gcc-10 (Ubuntu 10.3.0-1ubuntu1~20.04) 10.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.3-341-g8af24329-dirty
        # https://github.com/0day-ci/linux/commit/3209f59f4622e7c3fb8756081af92755afdf80fe
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Matthew-Wilcox-Oracle/Memory-folios/20210715-133101
        git checkout 3209f59f4622e7c3fb8756081af92755afdf80fe
        # save the attached .config to linux build tree
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash

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 >>)
   mm/page-writeback.c: note: in included file (through include/linux/rculist.h, include/linux/dcache.h, include/linux/fs.h):
   include/linux/rcupdate.h:716:9: sparse: sparse: context imbalance in 'account_page_redirty' - different lock contexts for basic block
   include/linux/rcupdate.h:716:9: sparse: sparse: context imbalance in '__folio_cancel_dirty' - different lock contexts for basic block
>> include/linux/rcupdate.h:716:9: sparse: sparse: context imbalance in 'folio_clear_dirty_for_io' - different lock contexts for basic block

vim +/folio_clear_dirty_for_io +716 include/linux/rcupdate.h

^1da177e4c3f415 Linus Torvalds   2005-04-16  691  
^1da177e4c3f415 Linus Torvalds   2005-04-16  692  /*
^1da177e4c3f415 Linus Torvalds   2005-04-16  693   * So where is rcu_write_lock()?  It does not exist, as there is no
^1da177e4c3f415 Linus Torvalds   2005-04-16  694   * way for writers to lock out RCU readers.  This is a feature, not
^1da177e4c3f415 Linus Torvalds   2005-04-16  695   * a bug -- this property is what provides RCU's performance benefits.
^1da177e4c3f415 Linus Torvalds   2005-04-16  696   * Of course, writers must coordinate with each other.  The normal
^1da177e4c3f415 Linus Torvalds   2005-04-16  697   * spinlock primitives work well for this, but any other technique may be
^1da177e4c3f415 Linus Torvalds   2005-04-16  698   * used as well.  RCU does not care how the writers keep out of each
^1da177e4c3f415 Linus Torvalds   2005-04-16  699   * others' way, as long as they do so.
^1da177e4c3f415 Linus Torvalds   2005-04-16  700   */
3d76c082907e8f8 Paul E. McKenney 2009-09-28  701  
3d76c082907e8f8 Paul E. McKenney 2009-09-28  702  /**
ca5ecddfa8fcbd9 Paul E. McKenney 2010-04-28  703   * rcu_read_unlock() - marks the end of an RCU read-side critical section.
3d76c082907e8f8 Paul E. McKenney 2009-09-28  704   *
0223846010750e2 Paul E. McKenney 2021-04-29  705   * In almost all situations, rcu_read_unlock() is immune from deadlock.
0223846010750e2 Paul E. McKenney 2021-04-29  706   * In recent kernels that have consolidated synchronize_sched() and
0223846010750e2 Paul E. McKenney 2021-04-29  707   * synchronize_rcu_bh() into synchronize_rcu(), this deadlock immunity
0223846010750e2 Paul E. McKenney 2021-04-29  708   * also extends to the scheduler's runqueue and priority-inheritance
0223846010750e2 Paul E. McKenney 2021-04-29  709   * spinlocks, courtesy of the quiescent-state deferral that is carried
0223846010750e2 Paul E. McKenney 2021-04-29  710   * out when rcu_read_unlock() is invoked with interrupts disabled.
f27bc4873fa8b75 Paul E. McKenney 2014-05-04  711   *
3d76c082907e8f8 Paul E. McKenney 2009-09-28  712   * See rcu_read_lock() for more information.
3d76c082907e8f8 Paul E. McKenney 2009-09-28  713   */
bc33f24bdca8b6e Paul E. McKenney 2009-08-22  714  static inline void rcu_read_unlock(void)
bc33f24bdca8b6e Paul E. McKenney 2009-08-22  715  {
f78f5b90c4ffa55 Paul E. McKenney 2015-06-18 @716  	RCU_LOCKDEP_WARN(!rcu_is_watching(),
bde23c6892878e4 Heiko Carstens   2012-02-01  717  			 "rcu_read_unlock() used illegally while idle");
bc33f24bdca8b6e Paul E. McKenney 2009-08-22  718  	__release(RCU);
bc33f24bdca8b6e Paul E. McKenney 2009-08-22  719  	__rcu_read_unlock();
d24209bb689e2c7 Paul E. McKenney 2015-01-21  720  	rcu_lock_release(&rcu_lock_map); /* Keep acq info for rls diags. */
bc33f24bdca8b6e Paul E. McKenney 2009-08-22  721  }
^1da177e4c3f415 Linus Torvalds   2005-04-16  722  

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