linux-kernel - [PATCH 4.9 122/130] [media] s5p-mfc: Fix clock management in s5p_mfc

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Date:   Tue, 24 Jan 2017 08:56:02 +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,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Mauro Carvalho Chehab <mchehab@...pensource.com>
Subject: [PATCH 4.9 122/130] [media] s5p-mfc: Fix clock management in s5p_mfc_release() function

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marek Szyprowski <m.szyprowski@...sung.com>

commit c0026c7bfb95c250c3e34fde59f96ad72fd730d6 upstream.

Clock control indirectly requires access to MFC device, so call it only
if we are sure that the device exists in s5p_mfc_release function.
s5p_mfc_remove() calls s5p_mfc_final_pm(), which releases all PM related
resources, including clocks, so any call to clocks related functions
is not valid after s5p_mfc_final_pm().

Fixes: d695c12 ("[media] media: s5p-mfc fix invalid memory access from
s5p_mfc_release()")

Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...pensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/media/platform/s5p-mfc/s5p_mfc.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/media/platform/s5p-mfc/s5p_mfc.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc.c
@@ -926,10 +926,11 @@ static int s5p_mfc_release(struct file *
 	mfc_debug_enter();
 	if (dev)
 		mutex_lock(&dev->mfc_mutex);
-	s5p_mfc_clock_on();
 	vb2_queue_release(&ctx->vq_src);
 	vb2_queue_release(&ctx->vq_dst);
 	if (dev) {
+		s5p_mfc_clock_on();
+
 		/* Mark context as idle */
 		clear_work_bit_irqsave(ctx);
 		/*
@@ -951,9 +952,9 @@ static int s5p_mfc_release(struct file *
 			if (s5p_mfc_power_off() < 0)
 				mfc_err("Power off failed\n");
 		}
+		mfc_debug(2, "Shutting down clock\n");
+		s5p_mfc_clock_off();
 	}
-	mfc_debug(2, "Shutting down clock\n");
-	s5p_mfc_clock_off();
 	if (dev)
 		dev->ctx[ctx->num] = NULL;
 	s5p_mfc_dec_ctrls_delete(ctx);