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| author | Hugh Dickins <hughd@google.com> | 2012-10-08 16:33:14 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:22:55 +0900 |
| commit | ec4d9f626d5908b6052c2973f37992f1db52e967 (patch) | |
| tree | c1c0dd99680061cb506797f37ed319eb2804329f /mm/truncate.c | |
| parent | 7ffc0edc49d0df5dac077c1830e2533b27d3a4ed (diff) | |
| download | linux-ec4d9f626d5908b6052c2973f37992f1db52e967.tar.gz linux-ec4d9f626d5908b6052c2973f37992f1db52e967.tar.bz2 linux-ec4d9f626d5908b6052c2973f37992f1db52e967.zip | |
mm: fix invalidate_complete_page2() lock ordering
In fuzzing with trinity, lockdep protested "possible irq lock inversion
dependency detected" when isolate_lru_page() reenabled interrupts while
still holding the supposedly irq-safe tree_lock:
invalidate_inode_pages2
invalidate_complete_page2
spin_lock_irq(&mapping->tree_lock)
clear_page_mlock
isolate_lru_page
spin_unlock_irq(&zone->lru_lock)
isolate_lru_page() is correct to enable interrupts unconditionally:
invalidate_complete_page2() is incorrect to call clear_page_mlock() while
holding tree_lock, which is supposed to nest inside lru_lock.
Both truncate_complete_page() and invalidate_complete_page() call
clear_page_mlock() before taking tree_lock to remove page from radix_tree.
I guess invalidate_complete_page2() preferred to test PageDirty (again)
under tree_lock before committing to the munlock; but since the page has
already been unmapped, its state is already somewhat inconsistent, and no
worse if clear_page_mlock() moved up.
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Deciphered-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ying Han <yinghan@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>
Diffstat (limited to 'mm/truncate.c')
| -rw-r--r-- | mm/truncate.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/truncate.c b/mm/truncate.c index 75801acdaac7..f38055cb8af6 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -394,11 +394,12 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page) if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) return 0; + clear_page_mlock(page); + spin_lock_irq(&mapping->tree_lock); if (PageDirty(page)) goto failed; - clear_page_mlock(page); BUG_ON(page_has_private(page)); __delete_from_page_cache(page); spin_unlock_irq(&mapping->tree_lock); |