Commit c93db7bb authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Dan Williams

dax: Check page->mapping isn't NULL

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: c2a7d2a1 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Cc: <stable@vger.kernel.org>
Reported-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 2e6e902d
......@@ -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;
/*
......
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