From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752883Ab3GXOOT (ORCPT ); Wed, 24 Jul 2013 10:14:19 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45836 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752324Ab3GXOGv (ORCPT ); Wed, 24 Jul 2013 10:06:51 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Linus Torvalds" , "Tomasz Figa" , "Vinod Koul" , "Jassi Brar" , "Kyungmin Park" , "Bartlomiej Zolnierkiewicz" Date: Wed, 24 Jul 2013 15:02:45 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [65/85] drivers/dma/pl330.c: fix locking in pl330_free_chan_resources() In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.101 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.49-rc1 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: Ben Hutchings --- drivers/dma/pl330.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -349,10 +349,10 @@ 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;