On Tue, Sep 18, 2012 at 08:51:47PM -0700, Hugh Dickins wrote: > 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 <levinsasha...@gmail.com> > Deciphered-by: Andrew Morton <a...@linux-foundation.org> > Signed-off-by: Hugh Dickins <hu...@google.com> > Cc: Mel Gorman <m...@csn.ul.ie> > Cc: Rik van Riel <r...@redhat.com> > Cc: Johannes Weiner <han...@cmpxchg.org> > Cc: Michel Lespinasse <wal...@google.com> > Cc: Ying Han <ying...@google.com> > Cc: sta...@vger.kernel.org
Acked-by: Mel Gorman <m...@csn.ul.ie> -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
