* [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock
@ 2013-11-05 10:01 Gu Zheng
2013-11-05 11:02 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Gu Zheng @ 2013-11-05 10:01 UTC (permalink / raw)
To: jfrederich, dsd, jon.nettleton, Greg Kroah-Hartman
Cc: devel, Tomi Valkeinen, Jean-Christophe PLAGNIOL-VILLARD, linux-kernel
The lock sequence of dcon_blank_fb(fb_info->lock ---> console_lock) is against
with the one of console_callback(console_lock ---> fb_info->lock), it'll
lead to a potential dead lock, so reorder the lock sequence of dcon_blank_fb
to avoid the potential dead lock.
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
---
drivers/staging/olpc_dcon/olpc_dcon.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/olpc_dcon/olpc_dcon.c b/drivers/staging/olpc_dcon/olpc_dcon.c
index 198595e..9db88d9 100644
--- a/drivers/staging/olpc_dcon/olpc_dcon.c
+++ b/drivers/staging/olpc_dcon/olpc_dcon.c
@@ -255,17 +255,19 @@ static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
{
int err;
+ console_lock();
if (!lock_fb_info(dcon->fbinfo)) {
+ console_unlock();
dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
return false;
}
- console_lock();
+
dcon->ignore_fb_events = true;
err = fb_blank(dcon->fbinfo,
blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
dcon->ignore_fb_events = false;
- console_unlock();
unlock_fb_info(dcon->fbinfo);
+ console_unlock();
if (err) {
dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",
--
1.7.7
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock
2013-11-05 10:01 [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock Gu Zheng
@ 2013-11-05 11:02 ` Dan Carpenter
2013-11-06 1:22 ` Gu Zheng
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2013-11-05 11:02 UTC (permalink / raw)
To: Gu Zheng
Cc: jfrederich, dsd, jon.nettleton, Greg Kroah-Hartman, devel,
Tomi Valkeinen, Jean-Christophe PLAGNIOL-VILLARD, linux-kernel
On Tue, Nov 05, 2013 at 06:01:00PM +0800, Gu Zheng wrote:
> The lock sequence of dcon_blank_fb(fb_info->lock ---> console_lock) is against
> with the one of console_callback(console_lock ---> fb_info->lock), it'll
> lead to a potential dead lock, so reorder the lock sequence of dcon_blank_fb
> to avoid the potential dead lock.
>
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Relax, Greg isn't taking new patches for another three weeks because the
merge window is open.
Also what happened to [PATCH 1/2]?
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock
2013-11-05 11:02 ` Dan Carpenter
@ 2013-11-06 1:22 ` Gu Zheng
2013-11-07 11:38 ` Dan Carpenter
0 siblings, 1 reply; 4+ messages in thread
From: Gu Zheng @ 2013-11-06 1:22 UTC (permalink / raw)
To: Dan Carpenter
Cc: jfrederich, dsd, jon.nettleton, Greg Kroah-Hartman, devel,
Tomi Valkeinen, Jean-Christophe PLAGNIOL-VILLARD, linux-kernel
Hi Dan,
On 11/05/2013 07:02 PM, Dan Carpenter wrote:
> On Tue, Nov 05, 2013 at 06:01:00PM +0800, Gu Zheng wrote:
>> The lock sequence of dcon_blank_fb(fb_info->lock ---> console_lock) is against
>> with the one of console_callback(console_lock ---> fb_info->lock), it'll
>> lead to a potential dead lock, so reorder the lock sequence of dcon_blank_fb
>> to avoid the potential dead lock.
>>
>> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
>
> Relax, Greg isn't taking new patches for another three weeks because the
> merge window is open.
Got it, I just want to gain some comments about this patch.
>
> Also what happened to [PATCH 1/2]?
It fixes the similar issue of fb subsystem.
https://patchwork.kernel.org/patch/3140121/
Regards,
Gu
>
> regards,
> dan carpenter
>
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock
2013-11-06 1:22 ` Gu Zheng
@ 2013-11-07 11:38 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2013-11-07 11:38 UTC (permalink / raw)
To: Gu Zheng
Cc: jfrederich, dsd, jon.nettleton, Greg Kroah-Hartman, devel,
Tomi Valkeinen, Jean-Christophe PLAGNIOL-VILLARD, linux-kernel
On Wed, Nov 06, 2013 at 09:22:36AM +0800, Gu Zheng wrote:
> Hi Dan,
> On 11/05/2013 07:02 PM, Dan Carpenter wrote:
>
> > On Tue, Nov 05, 2013 at 06:01:00PM +0800, Gu Zheng wrote:
> >> The lock sequence of dcon_blank_fb(fb_info->lock ---> console_lock) is against
> >> with the one of console_callback(console_lock ---> fb_info->lock), it'll
> >> lead to a potential dead lock, so reorder the lock sequence of dcon_blank_fb
> >> to avoid the potential dead lock.
> >>
> >> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> >
> > Relax, Greg isn't taking new patches for another three weeks because the
> > merge window is open.
>
> Got it, I just want to gain some comments about this patch.
>
If no one complains that means it is approved. :)
regards,
dan carpenter
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-11-07 11:41 UTC | newest]
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2013-11-05 10:01 [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock Gu Zheng
2013-11-05 11:02 ` Dan Carpenter
2013-11-06 1:22 ` Gu Zheng
2013-11-07 11:38 ` Dan Carpenter
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