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Message-ID: <4B7EEB6B.5070400@gmail.com>
Date: Fri, 19 Feb 2010 20:50:03 +0100
From: Roel Kluin <roel.kluin@...il.com>
To: "Karicheri, Muralidharan" <m-karicheri2@...com>
CC: Mauro Carvalho Chehab <mchehab@...radead.org>,
"linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] video_device: don't free_irq() an element past array
vpif_obj.dev[] and fix test
The first loop ends when platform_get_resource() returns NULL. Can it occur
that no platform_get_resource() succeeded? I think we should error return if
that happens. Could k grow larger than VPIF_DISPLAY_MAX_DEVICES there?
Should we err out in that case?
In the loop `for (i = 0; i < VPIF_DISPLAY_MAX_DEVICES; i++)' if
video_device_alloc() fails I think we correctly release the devices,
but we have to do more before we reach label vpif_int_err.
As mentioned, we left the first loop with a res of NULL, which is
dereferenced at label vpif_int_err. So we have to get the resource again,
however, k was incremented at the end of that loop as well. Also i used
as index in the second loop as well should point to res->end before going
to label vpif_int_err, to free all requested irqs. All this needs to be
done for later error labels as well, so a new label is added where this
occurs, alloc_vid_fail.
Variable k can't be reused in the third for-loop and at label probe_out.
As mentioned k is needed to get the resource in case a error and clean-up
is required.
If we reach label vpif_int_err, res shouldn't be NULL, since we
dereference it. Previously we had:
for (; k >= 0; k--) {
for (m = i; m >= res->start; m--)
free_irq(m, (void *)(&vpif_obj.dev[k]->channel_id));
res = platform_get_resource(pdev, IORESOURCE_IRQ, k-1);
m = res->end;
}
In the last iteration k equals 0, so we call platform_get_resource() with
-1 as a third argument. Since platform_get_resource() uses an unsigned it
is converted to 0xffffffff. platform_get_resource() fails for every index
and returns NULL. A test is lacking and we dereference NULL.
The error "VPIF IRQ request failed" should only be displayed when
request_irq() failed, not in the case of other errors.
Also I changed some indexes, so a few could be removed.
Signed-off-by: Roel Kluin <roel.kluin@...il.com>
---
There were some errors in the changelog and a signoff was missing.
> Ok. You are right! The ch_params[] is a table for keeping the information
> about different standards supported. For a given stdid in std_info, the function matches the stdid with that in the table and get the corresponding entry.
>>>> + if (k == VPIF_DISPLAY_MAX_DEVICES)
>>>> + k = VPIF_DISPLAY_MAX_DEVICES - 1;
>>
>> actually I think this is still not right. shouldn't it be be
>>
>> k = VPIF_DISPLAY_MAX_DEVICES - 1;
>
> What you mean here? What you suggest here is same as in your patch, right?
I must admit I did not test this, except with checkpatch.pl, but I think
the issues are real and should be fixed. Do you have comments?
drivers/media/video/davinci/vpif_display.c | 61 +++++++++++++++++++---------
1 files changed, 41 insertions(+), 20 deletions(-)
diff --git a/drivers/media/video/davinci/vpif_display.c b/drivers/media/video/davinci/vpif_display.c
index dfddef7..ae8ca94 100644
--- a/drivers/media/video/davinci/vpif_display.c
+++ b/drivers/media/video/davinci/vpif_display.c
@@ -383,7 +383,7 @@ static int vpif_get_std_info(struct channel_obj *ch)
int index;
std_info->stdid = vid_ch->stdid;
- if (!std_info)
+ if (!std_info->stdid)
return -1;
for (index = 0; index < ARRAY_SIZE(ch_params); index++) {
@@ -1423,7 +1423,7 @@ static __init int vpif_probe(struct platform_device *pdev)
{
struct vpif_subdev_info *subdevdata;
struct vpif_display_config *config;
- int i, j = 0, k, q, m, err = 0;
+ int i, j, k, err;
struct i2c_adapter *i2c_adap;
struct common_obj *common;
struct channel_obj *ch;
@@ -1452,12 +1452,18 @@ static __init int vpif_probe(struct platform_device *pdev)
if (request_irq(i, vpif_channel_isr, IRQF_DISABLED,
"DM646x_Display",
(void *)(&vpif_obj.dev[k]->channel_id))) {
+ i--;
err = -EBUSY;
+ vpif_err("VPIF IRQ request failed\n");
goto vpif_int_err;
}
}
k++;
+ if (k >= VPIF_DISPLAY_MAX_DEVICES)
+ break;
}
+ if (k == 0)
+ return -ENODEV;
for (i = 0; i < VPIF_DISPLAY_MAX_DEVICES; i++) {
@@ -1472,7 +1478,7 @@ static __init int vpif_probe(struct platform_device *pdev)
video_device_release(ch->video_dev);
}
err = -ENOMEM;
- goto vpif_int_err;
+ goto alloc_vid_fail;
}
/* Initialize field of video device */
@@ -1489,13 +1495,13 @@ static __init int vpif_probe(struct platform_device *pdev)
ch->video_dev = vfd;
}
- for (j = 0; j < VPIF_DISPLAY_MAX_DEVICES; j++) {
- ch = vpif_obj.dev[j];
+ for (i = 0; i < VPIF_DISPLAY_MAX_DEVICES; i++) {
+ ch = vpif_obj.dev[i];
/* Initialize field of the channel objects */
atomic_set(&ch->usrs, 0);
- for (k = 0; k < VPIF_NUMOBJECTS; k++) {
- ch->common[k].numbuffers = 0;
- common = &ch->common[k];
+ for (j = 0; j < VPIF_NUMOBJECTS; j++) {
+ ch->common[j].numbuffers = 0;
+ common = &ch->common[j];
common->io_usrs = 0;
common->started = 0;
spin_lock_init(&common->irqlock);
@@ -1506,12 +1512,12 @@ static __init int vpif_probe(struct platform_device *pdev)
common->ctop_off = common->cbtm_off = 0;
common->cur_frm = common->next_frm = NULL;
memset(&common->fmt, 0, sizeof(common->fmt));
- common->numbuffers = config_params.numbuffers[k];
+ common->numbuffers = config_params.numbuffers[j];
}
ch->initialized = 0;
- ch->channel_id = j;
- if (j < 2)
+ ch->channel_id = i;
+ if (i < 2)
ch->common[VPIF_VIDEO_INDEX].numbuffers =
config_params.numbuffers[ch->channel_id];
else
@@ -1529,7 +1535,7 @@ static __init int vpif_probe(struct platform_device *pdev)
(int)ch, (int)&ch->video_dev);
err = video_register_device(ch->video_dev,
- VFL_TYPE_GRABBER, (j ? 3 : 2));
+ VFL_TYPE_GRABBER, (i ? 3 : 2));
if (err < 0)
goto probe_out;
@@ -1567,20 +1573,35 @@ static __init int vpif_probe(struct platform_device *pdev)
probe_subdev_out:
kfree(vpif_obj.sd);
probe_out:
- for (k = 0; k < j; k++) {
- ch = vpif_obj.dev[k];
+ for (j = 0; j < i; j++) {
+ ch = vpif_obj.dev[j];
video_unregister_device(ch->video_dev);
video_device_release(ch->video_dev);
ch->video_dev = NULL;
}
+alloc_vid_fail:
+ while (k--) {
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, k);
+ if (res != NULL)
+ break;
+ vpif_err("Couldn't get resource %d, irqs not freed.\n", k);
+ }
+ if (res == NULL) {
+ vpif_err("Couldn't get any resource.\n");
+ return err;
+ }
+
+ i = res->end;
vpif_int_err:
v4l2_device_unregister(&vpif_obj.v4l2_dev);
- vpif_err("VPIF IRQ request failed\n");
- for (q = k; k >= 0; k--) {
- for (m = i; m >= res->start; m--)
- free_irq(m, (void *)(&vpif_obj.dev[k]->channel_id));
- res = platform_get_resource(pdev, IORESOURCE_IRQ, k-1);
- m = res->end;
+
+ for (j = i; j >= res->start; j--)
+ free_irq(j, (void *)(&vpif_obj.dev[k]->channel_id));
+
+ while (k--) {
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, k);
+ for (j = res->end; j >= res->start; j--)
+ free_irq(j, (void *)(&vpif_obj.dev[k]->channel_id));
}
return err;
--
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