From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935146Ab3GSCcF (ORCPT ); Thu, 18 Jul 2013 22:32:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37757 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935020Ab3GSCXq (ORCPT ); Thu, 18 Jul 2013 22:23:46 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bartlomiej Zolnierkiewicz , Kyungmin Park , Jassi Brar , Vinod Koul , Tomasz Figa , Andrew Morton , Linus Torvalds Subject: [ 18/18] drivers/dma/pl330.c: fix locking in pl330_free_chan_resources() Date: Thu, 18 Jul 2013 19:23:33 -0700 Message-Id: <20130719021050.204528358@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <20130719021048.965829361@linuxfoundation.org> References: <20130719021048.965829361@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bartlomiej Zolnierkiewicz commit da331ba8e9c5de72a27e50f71105395bba6eebe0 upstream. tasklet_kill() may sleep so call it before taking pch->lock. Fixes following lockup: BUG: scheduling while atomic: cat/2383/0x00000002 Modules linked in: unwind_backtrace+0x0/0xfc __schedule_bug+0x4c/0x58 __schedule+0x690/0x6e0 sys_sched_yield+0x70/0x78 tasklet_kill+0x34/0x8c pl330_free_chan_resources+0x24/0x88 dma_chan_put+0x4c/0x50 [...] BUG: spinlock lockup suspected on CPU#0, swapper/0/0 lock: 0xe52aa04c, .magic: dead4ead, .owner: cat/2383, .owner_cpu: 1 unwind_backtrace+0x0/0xfc do_raw_spin_lock+0x194/0x204 _raw_spin_lock_irqsave+0x20/0x28 pl330_tasklet+0x2c/0x5a8 tasklet_action+0xfc/0x114 __do_softirq+0xe4/0x19c irq_exit+0x98/0x9c handle_IPI+0x124/0x16c gic_handle_irq+0x64/0x68 __irq_svc+0x40/0x70 cpuidle_wrap_enter+0x4c/0xa0 cpuidle_enter_state+0x18/0x68 cpuidle_idle_call+0xac/0xe0 cpu_idle+0xac/0xf0 Signed-off-by: Bartlomiej Zolnierkiewicz Signed-off-by: Kyungmin Park Acked-by: Jassi Brar Cc: Vinod Koul Cc: Tomasz Figa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/dma/pl330.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -281,10 +281,10 @@ static void pl330_free_chan_resources(st struct dma_pl330_chan *pch = to_pchan(chan); unsigned long flags; - spin_lock_irqsave(&pch->lock, flags); - tasklet_kill(&pch->task); + spin_lock_irqsave(&pch->lock, flags); + pl330_release_channel(pch->pl330_chid); pch->pl330_chid = NULL;