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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2014-02-06 12:04:28 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-20 11:06:11 -0800
commit7e405afc255142ceb5d8cc3d97a7cffac46f0e4e (patch)
tree692d37667fd923f8367156bc48fa8454a10cf036
parentdce0b4fcf24d431eea39d7675c72a8b830ae6a65 (diff)
downloadlinaro-lsk-7e405afc255142ceb5d8cc3d97a7cffac46f0e4e.tar.gz
mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq
commit 227d53b397a32a7614667b3ecaf1d89902fb6c12 upstream. To use spin_{un}lock_irq is dangerous if caller disabled interrupt. During aio buffer migration, we have a possibility to see the following call stack. aio_migratepage [disable interrupt] migrate_page_copy clear_page_dirty_for_io set_page_dirty __set_page_dirty_buffers __set_page_dirty spin_lock_irq This mean, current aio migration is a deadlockable. spin_lock_irqsave is a safer alternative and we should use it. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reported-by: David Rientjes rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/buffer.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index d2a4d1bb2d5..75964d73444 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -620,14 +620,16 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode);
static void __set_page_dirty(struct page *page,
struct address_space *mapping, int warn)
{
- spin_lock_irq(&mapping->tree_lock);
+ unsigned long flags;
+
+ spin_lock_irqsave(&mapping->tree_lock, flags);
if (page->mapping) { /* Race with truncate? */
WARN_ON_ONCE(warn && !PageUptodate(page));
account_page_dirtied(page, mapping);
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
- spin_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irqrestore(&mapping->tree_lock, flags);
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
}