4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Waiman Long <long...@redhat.com>

commit 03eeafdd9ab06a770d42c2b264d50dff7e2f4eee upstream.

It was found that the use of up_read_non_owner() in NFS was causing
the following warning when DEBUG_RWSEMS was configured.

  DEBUG_LOCKS_WARN_ON(sem->owner != ((struct task_struct *)(1UL << 0)))

Looking into the rwsem.c file, it was discovered that the corresponding
down_read_non_owner() function was not setting the owner field properly.
This is fixed now, and the warning should be gone.

Fixes: 5149cbac4235 ("locking/rwsem: Add DEBUG_RWSEMS to look for lock/unlock 
mismatches")
Signed-off-by: Waiman Long <long...@redhat.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Tested-by: Gavin Schenk <g.sch...@eckelmann.de>
Cc: Davidlohr Bueso <d...@stgolabs.net>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: linux-...@vger.kernel.org
Cc: sta...@vger.kernel.org
Link: 
https://lkml.kernel.org/r/1527168398-4291-1-git-send-email-long...@redhat.com
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 kernel/locking/rwsem.c |    1 +
 1 file changed, 1 insertion(+)

--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -181,6 +181,7 @@ void down_read_non_owner(struct rw_semap
        might_sleep();
 
        __down_read(sem);
+       rwsem_set_reader_owned(sem);
 }
 
 EXPORT_SYMBOL(down_read_non_owner);


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