Hi Fengguang, Thanks for your test and reporting.
On Sun, Jan 12, 2014 at 12:14 AM, kernel test robot <fengguang...@intel.com> wrote: > Greetings, > > I got the below dmesg and the first bad commit is > > commit 97e890b9c839c191a500c3a19bfb4539f65c70be > Author: Ming Lei <tom.leim...@gmail.com> > AuthorDate: Fri Jan 10 12:41:46 2014 +1100 > Commit: Stephen Rothwell <s...@canb.auug.org.au> > CommitDate: Fri Jan 10 12:41:46 2014 +1100 > > lib/percpu_counter.c: disable local irq when updating percpu couter > > __percpu_counter_add() may be called in softirq/hardirq handler (such as, > blk_mq_queue_exit() is typically called in hardirq/softirq handler), so we > need to disable local irq when updating the percpu counter, otherwise > counts may be lost. > > The patch fixes problem that 'rmmod null_blk' may hang in > blk_cleanup_queue() > because of miscounting of request_queue->mq_usage_counter. > > Signed-off-by: Ming Lei <tom.leim...@gmail.com> > Cc: Paul Gortmaker <paul.gortma...@windriver.com> > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Shaohua Li <s...@fusionio.com> > Cc: Jens Axboe <ax...@kernel.dk> > Cc: Fan Du <fan...@windriver.com> > Cc: Tejun Heo <t...@kernel.org> > Cc: <sta...@vger.kernel.org> > Signed-off-by: Andrew Morton <a...@linux-foundation.org> > > +-----------------------------------------------------------+----+ > | | | > +-----------------------------------------------------------+----+ > | boot_successes | 0 | > | boot_failures | 19 | > | WARNING:CPU:PID:at_kernel/locking/lockdep.c:check_flags() | 19 | > +-----------------------------------------------------------+----+ > > [ 8.021637] Freeing unused kernel memory: 816K (ffff880001934000 - > ffff880001a00000) > > [ 8.093354] ------------[ cut here ]------------ > [ 8.095469] WARNING: CPU: 1 PID: 1 at kernel/locking/lockdep.c:3537 > check_flags+0x77/0x1ba() > [ 8.095469] DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled) The warning is caused by the added raw_local_irq_save(), which should have been local_irq_save(flags). Actually, it is a false positive. Andrew, considered that your approach may be more efficient than this one since preempt_disable()/preempt_enable() can be removed too. So could you prepare one patch for fixing the problem? Or if you are busy, I'd like to do it. Thanks, -- Ming Lei -- 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/
