lkml.org 
[lkml]   [2017]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[char-misc 1/2 for 4.11] mei: fix deadlock on mei reset
Date
This patch fixes 'mei: synchronize irq before initiating a reset'
The patch had introduced a deadlock between irq thread and mei_reset()
as they are both holding the same device lock.

---> device_lock:
mei_reset()
<---- interrupt thread
device_lock
---> synchornize_irq()
wait on interrupt thread == (dead lock)

The fix is to call synchronize_irq
prior to call locked mei_reset function.

Cc: <stable@vger.kernel.org> #4.10+
Fixes: f302bb0de6ac (mei: synchronize irq before initiating a reset)
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
drivers/misc/mei/init.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index cfb1cdf176fa..13c55b8f9261 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -124,8 +124,6 @@ int mei_reset(struct mei_device *dev)

mei_clear_interrupts(dev);

- mei_synchronize_irq(dev);
-
/* we're already in reset, cancel the init timer
* if the reset was called due the hbm protocol error
* we need to call it before hw start
@@ -304,6 +302,9 @@ static void mei_reset_work(struct work_struct *work)
container_of(work, struct mei_device, reset_work);
int ret;

+ mei_clear_interrupts(dev);
+ mei_synchronize_irq(dev);
+
mutex_lock(&dev->device_lock);

ret = mei_reset(dev);
@@ -328,6 +329,9 @@ void mei_stop(struct mei_device *dev)

mei_cancel_work(dev);

+ mei_clear_interrupts(dev);
+ mei_synchronize_irq(dev);
+
mutex_lock(&dev->device_lock);

dev->dev_state = MEI_DEV_POWER_DOWN;
--
2.7.4
\
 
 \ /
  Last update: 2017-03-05 20:41    [W:0.059 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site