From 7e405afc255142ceb5d8cc3d97a7cffac46f0e4e Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Thu, 6 Feb 2014 12:04:28 -0800 Subject: [PATCH] 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 Reported-by: David Rientjes rientjes@google.com> Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/buffer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index d2a4d1bb2d57..75964d734444 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); } -- 2.34.1