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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>
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commit 227d53b397a32a7614667b3ecaf1d89902fb6c12 1 parent 7bc35fd
@kosaki kosaki authored committed
Showing with 4 additions and 2 deletions.
  1. +4 −2 fs/buffer.c
View
6 fs/buffer.c
@@ -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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