Messages in this thread Patch in this message | | | From | Luis Henriques <> | Subject | [PATCH 3.5 15/60] mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq | Date | Fri, 21 Feb 2014 13:00:42 +0000 |
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3.5.7.31 -stable review patch. If anyone has any objections, please let me know.
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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
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: Luis Henriques <luis.henriques@canonical.com> --- fs/buffer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c index 2c78739..01d673c 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -613,14 +613,16 @@ 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); } -- 1.9.0
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