[PATCH 3.4 02/24] mm: __set_page_dirty_nobuffers() uses spin_lock_irqsave() instead of spin_lock_irq()

Greg Kroah-Hartman
2014-02-18T22:46:08Z

From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

commit a85d9df1ea1d23682a0ed1e100e6965006595d06 upstream.

During aio stress test, we observed the following lockdep warning. This
mean AIO+numa_balancing is currently deadlockable.

The problem is, aio_migratepage disable interrupt, but
__set_page_dirty_nobuffers unintentionally enable it again.

Generally, all helper function should use spin_lock_irqsave() instead of
spin_lock_irq() because they don't know caller at all.

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&(&ctx->completion_lock)->rlock);
<Interrupt>
lock(&(&ctx->completion_lock)->rlock);

*** DEADLOCK ***

dump_stack+0x19/0x1b
print_usage_bug+0x1f7/0x208
mark_lock+0x21d/0x2a0
mark_held_locks+0xb9/0x140
trace_hardirqs_on_caller+0x105/0x1d0
trace_hardirqs_on+0xd/0x10
_raw_spin_unlock_irq+0x2c/0x50
__set_page_dirty_nobuffers+0x8c/0xf0
migrate_page_copy+0x434/0x540
aio_migratepage+0xb1/0x140
move_to_new_page+0x7d/0x230
migrate_pages+0x5e5/0x700
migrate_misplaced_page+0xbc/0xf0
do_numa_page+0x102/0x190
handle_pte_fault+0x241/0x970
handle_mm_fault+0x265/0x370
__do_page_fault+0x172/0x5a0
do_page_fault+0x1a/0x70
page_fault+0x28/0x30

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Acked-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>

---
mm/page-writeback.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1993,11 +1993,12 @@ int __set_page_dirty_nobuffers(struct pa
if (!TestSetPageDirty(page)) {
struct address_space *mapping = page_mapping(page);
struct address_space *mapping2;
+ unsigned long flags;

if (!mapping)
return 1;

- spin_lock_irq(&mapping->tree_lock);
+ spin_lock_irqsave(&mapping->tree_lock, flags);
mapping2 = page_mapping(page);
if (mapping2) { /* Race with truncate? */
BUG_ON(mapping2 != mapping);
@@ -2006,7 +2007,7 @@ int __set_page_dirty_nobuffers(struct pa
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);
if (mapping->host) {
/* !PageAnon && !swapper_space */
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);