Commit 227d53b3 authored Feb 06, 2014 by KOSAKI Motohiro Committed by Linus Torvalds Feb 06, 2014

mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq



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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 7bc35fdd

fs/buffer.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -654,14 +654,16 @@ 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);
		}

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