From: Gu Zheng <guz.fnst@cn.fujitsu.com>
To: jfrederich@gmail.com, dsd@laptop.org, jon.nettleton@gmail.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: devel@driverdev.osuosl.org,
Tomi Valkeinen <tomi.valkeinen@ti.com>,
Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock
Date: Tue, 05 Nov 2013 18:01:00 +0800 [thread overview]
Message-ID: <5278C1DC.9000609@cn.fujitsu.com> (raw)
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
next reply other threads:[~2013-11-05 10:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-05 10:01 Gu Zheng [this message]
2013-11-05 11:02 ` [RESEND PATCH 2/2] staging/olpc_docn: reorder the lock sequence to avoid potential dead lock Dan Carpenter
2013-11-06 1:22 ` Gu Zheng
2013-11-07 11:38 ` Dan Carpenter
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