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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Peter Griffin <peter.griffin@linaro.org>,
        Rob Herring <robh@kernel.org>, Daniel Vetter <daniel@ffwll.ch>,
        Qiang Yu <yuq825@gmail.com>, Sasha Levin <sashal@kernel.org>,
        dri-devel@lists.freedesktop.org
Subject: [PATCH AUTOSEL 5.2 001/171] drm/lima: handle shared irq case for lima_pp_bcast_irq_handler
Date:   Thu, 18 Jul 2019 23:53:52 -0400
Message-Id: <20190719035643.14300-1-sashal@kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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From: Peter Griffin <peter.griffin@linaro.org>

[ Upstream commit 409c53f07a81f8db122c461f3255c6f43558c881 ]

On Hikey board all lima ip blocks are shared with one irq.
This patch avoids a NULL ptr deref crash on this platform
on startup. Tested with Weston and kmscube.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Qiang Yu <yuq825@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1555662781-22570-7-git-send-email-peter.griffin@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/lima/lima_pp.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/lima/lima_pp.c b/drivers/gpu/drm/lima/lima_pp.c
index d29721e177bf..8fef224b93c8 100644
--- a/drivers/gpu/drm/lima/lima_pp.c
+++ b/drivers/gpu/drm/lima/lima_pp.c
@@ -64,7 +64,13 @@ static irqreturn_t lima_pp_bcast_irq_handler(int irq, void *data)
 	struct lima_ip *pp_bcast = data;
 	struct lima_device *dev = pp_bcast->dev;
 	struct lima_sched_pipe *pipe = dev->pipe + lima_pipe_pp;
-	struct drm_lima_m450_pp_frame *frame = pipe->current_task->frame;
+	struct drm_lima_m450_pp_frame *frame;
+
+	/* for shared irq case */
+	if (!pipe->current_task)
+		return IRQ_NONE;
+
+	frame = pipe->current_task->frame;
 
 	for (i = 0; i < frame->num_pp; i++) {
 		struct lima_ip *ip = pipe->processor[i];
-- 
2.20.1