From: Matthew Wilcox <willy@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Dave Jiang <dave.jiang@intel.com>,
linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
stable@vger.kernel.org
Subject: [PATCH 1/2] dax: Check page->mapping isn't NULL
Date: Tue, 27 Nov 2018 13:16:33 -0800 [thread overview]
Message-ID: <20181127211634.4995-2-willy@infradead.org> (raw)
In-Reply-To: <20181127211634.4995-1-willy@infradead.org>
If we race with inode destroy, it's possible for page->mapping to be
NULL before we even enter this routine, as well as after having slept
waiting for the dax entry to become unlocked.
Fixes: c2a7d2a11552 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Cc: stable@vger.kernel.org
Reported-by: Jan Kara <jack@suse.cz>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
fs/dax.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/dax.c b/fs/dax.c
index 9bcce89ea18e..e69fc231833b 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -365,7 +365,7 @@ bool dax_lock_mapping_entry(struct page *page)
struct address_space *mapping = READ_ONCE(page->mapping);
locked = false;
- if (!dax_mapping(mapping))
+ if (!mapping || !dax_mapping(mapping))
break;
/*
--
2.19.1
next prev parent reply other threads:[~2018-11-28 8:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-27 21:16 [PATCH 0/2] Two DAX fixes for 4.20 Matthew Wilcox
2018-11-27 21:16 ` Matthew Wilcox [this message]
2018-11-28 9:18 ` [PATCH 1/2] dax: Check page->mapping isn't NULL Johannes Thumshirn
2018-11-28 11:46 ` Jan Kara
2018-11-27 21:16 ` [PATCH 2/2] dax: Don't access a freed inode Matthew Wilcox
2018-11-28 11:53 ` Jan Kara
2018-11-28 17:08 ` Dan Williams
2018-11-28 17:10 ` Matthew Wilcox
2018-11-28 19:44 ` [PATCH v2] " Dan Williams
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