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 <[email protected]> > Deciphered-by: Andrew Morton <[email protected]> > Signed-off-by: Hugh Dickins <[email protected]> > Cc: Mel Gorman <[email protected]> > Cc: Rik van Riel <[email protected]> > Cc: Johannes Weiner <[email protected]> > Cc: Michel Lespinasse <[email protected]> > Cc: Ying Han <[email protected]> > Cc: [email protected]
Acked-by: Johannes Weiner <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
