commit 9ba6873e1603988adf97dd5abe18936a2aeff1fd
author Greg Kroah-Hartman <gregkh@linuxfoundation.org> Sun Sep 30 06:19:38 2018 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Sun Sep 30 06:19:38 2018 -0700
tree aed33e2f126698f0b60cc69b08b5067ea3f0ce41
parent 291d0e5d81e101392379217b06251fe8c27f1f80
parent f52afc93cd018fe6910133a05d44671192d1aeb0

Merge tag 'libnvdimm-fixes2-4.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Dan writes:
  "filesystem-dax for 4.19-rc6

   Fix a deadlock in the new for 4.19 dax_lock_mapping_entry() routine."

* tag 'libnvdimm-fixes2-4.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: Fix deadlock in dax_lock_mapping_entry()

fs/dax.c

diff --git a/fs/dax.c b/fs/dax.c
index b68ce48..4becbf1 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -447,6 +447,7 @@
 			xa_unlock_irq(&mapping->i_pages);
 			break;
 		} else if (IS_ERR(entry)) {
+			xa_unlock_irq(&mapping->i_pages);
 			WARN_ON_ONCE(PTR_ERR(entry) != -EAGAIN);
 			continue;
 		}