The .buf_queue() V4L2 driver method is called under
spinlock_irqsave(q->irqlock,...), don't take the lock again inside the
function.
Reported-by: Antonio Ospite <ospite@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
---
Subject: Re: [BUG] pxa_camera: possible recursive locking detected
On Tue, 4 Aug 2009, Antonio Ospite wrote:
> Hi,
>
> verified to be present in linux-2.6.31-rc5, here's some info dumped
> from RAM, since the machine hangs, sorry if it is not complete but I
> couldn't get anything better for now, nothing is printed on
> the screen.
You're right, thanks for the report. Does the patch below fix the problem?
It only gets a bit tricky in mx3_camera.c, will have to test.
diff --git a/drivers/media/video/mx1_camera.c b/drivers/media/video/mx1_camera.c
index 9632cb1..3e95c6d 100644
--- a/drivers/media/video/mx1_camera.c
+++ b/drivers/media/video/mx1_camera.c
@@ -235,6 +235,7 @@ static int mx1_camera_setup_dma(struct mx1_camera_dev *pcdev)
return ret;
}
+/* Called under spinlock_irqsave(&pcdev->lock, ...) */
static void mx1_videobuf_queue(struct videobuf_queue *vq,
struct videobuf_buffer *vb)
{
@@ -247,8 +248,6 @@ static void mx1_videobuf_queue(struct videobuf_queue *vq,
dev_dbg(icd->dev.parent, "%s (vb=0x%p) 0x%08lx %d\n", __func__,
vb, vb->baddr, vb->bsize);
- spin_lock_irqsave(&pcdev->lock, flags);
-
list_add_tail(&vb->queue, &pcdev->capture);
vb->state = VIDEOBUF_ACTIVE;
@@ -265,8 +264,6 @@ static void mx1_videobuf_queue(struct videobuf_queue *vq,
__raw_writel(temp, pcdev->base + CSICR1);
}
}
-
- spin_unlock_irqrestore(&pcdev->lock, flags);
}
static void mx1_videobuf_release(struct videobuf_queue *vq,
diff --git a/drivers/media/video/mx3_camera.c b/drivers/media/video/mx3_camera.c
index 6572ce7..1c70165 100644
--- a/drivers/media/video/mx3_camera.c
+++ b/drivers/media/video/mx3_camera.c
@@ -332,7 +332,10 @@ static enum pixel_fmt fourcc_to_ipu_pix(__u32 fourcc)
}
}
-/* Called with .vb_lock held */
+/*
+ * Called with .vb_lock mutex held and
+ * under spinlock_irqsave(&mx3_cam->lock, ...)
+ */
static void mx3_videobuf_queue(struct videobuf_queue *vq,
struct videobuf_buffer *vb)
{
@@ -348,6 +351,8 @@ static void mx3_videobuf_queue(struct videobuf_queue *vq,
dma_cookie_t cookie;
unsigned long flags;
+ BUG_ON(!irqs_disabled());
+
/* This is the configuration of one sg-element */
video->out_pixel_fmt = fourcc_to_ipu_pix(data_fmt->fourcc);
video->out_width = icd->user_width;
@@ -359,8 +364,6 @@ static void mx3_videobuf_queue(struct videobuf_queue *vq,
memset((void *)vb->baddr, 0xaa, vb->bsize);
#endif
- spin_lock_irqsave(&mx3_cam->lock, flags);
-
list_add_tail(&vb->queue, &mx3_cam->capture);
if (!mx3_cam->active) {
@@ -370,7 +373,7 @@ static void mx3_videobuf_queue(struct videobuf_queue *vq,
vb->state = VIDEOBUF_QUEUED;
}
- spin_unlock_irqrestore(&mx3_cam->lock, flags);
+ spin_unlock_irq(&mx3_cam->lock);
cookie = txd->tx_submit(txd);
dev_dbg(icd->dev.parent, "Submitted cookie %d DMA 0x%08x\n",
@@ -381,14 +384,12 @@ static void mx3_videobuf_queue(struct videobuf_queue *vq,
/* Submit error */
vb->state = VIDEOBUF_PREPARED;
- spin_lock_irqsave(&mx3_cam->lock, flags);
+ spin_lock_irq(&mx3_cam->lock);
list_del_init(&vb->queue);
if (mx3_cam->active == buf)
mx3_cam->active = NULL;
-
- spin_unlock_irqrestore(&mx3_cam->lock, flags);
}
/* Called with .vb_lock held */
diff --git a/drivers/media/video/pxa_camera.c b/drivers/media/video/pxa_camera.c
index 7c86ef9..77be871 100644
--- a/drivers/media/video/pxa_camera.c
+++ b/drivers/media/video/pxa_camera.c
@@ -617,6 +617,7 @@ static void pxa_camera_stop_capture(struct pxa_camera_dev *pcdev)
dev_dbg(pcdev->soc_host.v4l2_dev.dev, "%s\n", __func__);
}
+/* Called under spinlock_irqsave(&pcdev->lock, ...) */
static void pxa_videobuf_queue(struct videobuf_queue *vq,
struct videobuf_buffer *vb)
{
@@ -629,8 +630,6 @@ static void pxa_videobuf_queue(struct videobuf_queue *vq,
dev_dbg(icd->dev.parent, "%s (vb=0x%p) 0x%08lx %d active=%p\n",
__func__, vb, vb->baddr, vb->bsize, pcdev->active);
- spin_lock_irqsave(&pcdev->lock, flags);
-
list_add_tail(&vb->queue, &pcdev->capture);
vb->state = VIDEOBUF_ACTIVE;
@@ -638,8 +637,6 @@ static void pxa_videobuf_queue(struct videobuf_queue *vq,
if (!pcdev->active)
pxa_camera_start_capture(pcdev);
-
- spin_unlock_irqrestore(&pcdev->lock, flags);
}
static void pxa_videobuf_release(struct videobuf_queue *vq,
diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c
index 0aacb31..ce808a1 100644
--- a/drivers/media/video/sh_mobile_ceu_camera.c
+++ b/drivers/media/video/sh_mobile_ceu_camera.c
@@ -304,6 +304,7 @@ out:
return ret;
}
+/* Called under spinlock_irqsave(&pcdev->lock, ...) */
static void sh_mobile_ceu_videobuf_queue(struct videobuf_queue *vq,
struct videobuf_buffer *vb)
{
@@ -315,7 +316,6 @@ static void sh_mobile_ceu_videobuf_queue(struct videobuf_queue *vq,
dev_dbg(icd->dev.parent, "%s (vb=0x%p) 0x%08lx %zd\n", __func__,
vb, vb->baddr, vb->bsize);
- spin_lock_irqsave(&pcdev->lock, flags);
vb->state = VIDEOBUF_QUEUED;
list_add_tail(&vb->queue, &pcdev->capture);
@@ -323,8 +323,6 @@ static void sh_mobile_ceu_videobuf_queue(struct videobuf_queue *vq,
pcdev->active = vb;
sh_mobile_ceu_capture(pcdev);
}
-
- spin_unlock_irqrestore(&pcdev->lock, flags);
}
static void sh_mobile_ceu_videobuf_release(struct videobuf_queue *vq,
--
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