linux-kernel - [PATCH 4.9 85/88] dmaengine: coh901318: Fix a double lock bug in dma_tc

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Date:   Tue, 10 Mar 2020 13:39:33 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Dan Carpenter <dan.carpenter@...cle.com>,
        Vinod Koul <vkoul@...nel.org>
Subject: [PATCH 4.9 85/88] dmaengine: coh901318: Fix a double lock bug in dma_tc_handle()

From: Dan Carpenter <dan.carpenter@...cle.com>

commit 36d5d22090d13fd3a7a8c9663a711cbe6970aac8 upstream.

The caller is already holding the lock so this will deadlock.

Fixes: 0b58828c923e ("DMAENGINE: COH 901 318 remove irq counting")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Link: https://lore.kernel.org/r/20200217144050.3i4ymbytogod4ijn@kili.mountain
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma/coh901318.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -1944,8 +1944,6 @@ static void dma_tc_handle(struct coh9013
 		return;
 	}
 
-	spin_lock(&cohc->lock);
-
 	/*
 	 * When we reach this point, at least one queue item
 	 * should have been moved over from cohc->queue to
@@ -1966,8 +1964,6 @@ static void dma_tc_handle(struct coh9013
 	if (coh901318_queue_start(cohc) == NULL)
 		cohc->busy = 0;
 
-	spin_unlock(&cohc->lock);
-
 	/*
 	 * This tasklet will remove items from cohc->active
 	 * and thus terminates them.