linux-kernel - [PATCH] dmaengine: pl330: Fix hang on dmaengine_terminate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-id: <1432168449-18850-1-git-send-email-k.kozlowski@samsung.com>
Date:	Thu, 21 May 2015 09:34:09 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Dan Williams <dan.j.williams@...el.com>,
	Vinod Koul <vinod.koul@...el.com>, dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	stable@...r.kernel.org,
	Dinh Nguyen <dinguyen@...nsource.altera.com>
Subject: [PATCH] dmaengine: pl330: Fix hang on dmaengine_terminate_all on
 certain boards

The pl330 device could hang infinitely on certain boards when DMA
channels are terminated.

It was caused by lack of runtime resume when executing
pl330_terminate_all() which calls the _stop() function. _stop() accesses
device register and can loop infinitely while checking for device state.

The hang was confirmed by Dinh Nguyen on Altera SOCFPGA Cyclone V
board during boot. It can be also triggered with:

$ echo 1 > /sys/module/dmatest/parameters/iterations
$ echo dma1chan0 > /sys/module/dmatest/parameters/channel
$ echo 1 > /sys/module/dmatest/parameters/run
$ sleep 1
$ cat /sys/module/dmatest/parameters/run

Reported-by: Dinh Nguyen <dinguyen@...nsource.altera.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
Fixes: ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12")
Cc: <stable@...r.kernel.org>
Cc: Dinh Nguyen <dinguyen@...nsource.altera.com>
---
 drivers/dma/pl330.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index a7d9d3029b14..340f9e607cd8 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2127,6 +2127,7 @@ static int pl330_terminate_all(struct dma_chan *chan)
 	struct pl330_dmac *pl330 = pch->dmac;
 	LIST_HEAD(list);
 
+	pm_runtime_get_sync(pl330->ddma.dev);
 	spin_lock_irqsave(&pch->lock, flags);
 	spin_lock(&pl330->lock);
 	_stop(pch->thread);
@@ -2151,6 +2152,8 @@ static int pl330_terminate_all(struct dma_chan *chan)
 	list_splice_tail_init(&pch->work_list, &pl330->desc_pool);
 	list_splice_tail_init(&pch->completed_list, &pl330->desc_pool);
 	spin_unlock_irqrestore(&pch->lock, flags);
+	pm_runtime_mark_last_busy(pl330->ddma.dev);
+	pm_runtime_put_autosuspend(pl330->ddma.dev);
 
 	return 0;
 }
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/