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[GIT,PULL] filesystem-dax fix for 4.19-rc6

Message ID 1538273814.24243.65.camel@intel.com (mailing list archive)
State New, archived
Headers show
Series [GIT,PULL] filesystem-dax fix for 4.19-rc6 | expand

Pull-request

git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm tags/libnvdimm-fixes2-4.19-rc6

Commit Message

Dan Williams Sept. 30, 2018, 2:16 a.m. UTC
Hi Greg, please pull from...

  git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm tags/libnvdimm-fixes2-4.19-rc6

...to receive one more urgent fix for 4.19-rc6.

---

The following changes since commit 6bf4ca7fbc85d80446ac01c0d1d77db4d91a6d84:

  Linux 4.19-rc5 (2018-09-23 19:15:18 +0200)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm tags/libnvdimm-fixes2-4.19-rc6

for you to fetch changes up to f52afc93cd018fe6910133a05d44671192d1aeb0:

  dax: Fix deadlock in dax_lock_mapping_entry() (2018-09-27 10:56:15 -0700)

----------------------------------------------------------------
filesystem-dax for 4.19-rc6

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

----------------------------------------------------------------
Jan Kara (1):
      dax: Fix deadlock in dax_lock_mapping_entry()

 fs/dax.c | 1 +
 1 file changed, 1 insertion(+)

commit f52afc93cd018fe6910133a05d44671192d1aeb0
Author: Jan Kara <jack@suse.cz>
Date:   Thu Sep 27 13:23:32 2018 +0200

    dax: Fix deadlock in dax_lock_mapping_entry()
    
    When dax_lock_mapping_entry() has to sleep to obtain entry lock, it will
    fail to unlock mapping->i_pages spinlock and thus immediately deadlock
    against itself when retrying to grab the entry lock again. Fix the
    problem by unlocking mapping->i_pages before retrying.
    
    Fixes: c2a7d2a11552 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
    Reported-by: Barret Rhoden <brho@google.com>
    Signed-off-by: Jan Kara <jack@suse.cz>
    Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Comments

Greg KH Sept. 30, 2018, 1:38 p.m. UTC | #1
On Sun, Sep 30, 2018 at 02:16:57AM +0000, Williams, Dan J wrote:
> Hi Greg, please pull from...
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm tags/libnvdimm-fixes2-4.19-rc6
> 
> ...to receive one more urgent fix for 4.19-rc6.

Now pulled, thanks.

greg k-h
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Patch

diff --git a/fs/dax.c b/fs/dax.c
index f32d7125ad0f..e4ef8af31aa6 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -447,6 +447,7 @@  bool dax_lock_mapping_entry(struct page *page)
                        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;
                }