On Sun, 6 Apr 2014 13:24:36 -0700
Dmitry Torokhov [off-list ref] wrote:

On Sun, Apr 06, 2014 at 12:54:50AM +0400, Alexey Khoroshilov wrote:

quoted

pcap_keys_handler() calls ezx_pcap_read() that calls mutex_lock().
pcap_keys_handler() is registered as nonthreaded irq handler,
that means sleeping function is called in irq handler.

The patch makes a switch to threaded irq handling.
Compile tested only.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <redacted>
---
 drivers/input/misc/pcap_keys.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/input/misc/pcap_keys.c b/drivers/input/misc/pcap_keys.c
index cd230365166e..2a10f3a30969 100644
--- a/drivers/input/misc/pcap_keys.c
+++ b/drivers/input/misc/pcap_keys.c

@@ -79,13 +79,15 @@ static int pcap_keys_probe(struct platform_device *pdev)
 	if (err)
 		goto fail_allocate;
 
-	err = request_irq(pcap_to_irq(pcap_keys->pcap, PCAP_IRQ_ONOFF),
-			pcap_keys_handler, 0, "Power key", pcap_keys);
+	err = request_threaded_irq(pcap_to_irq(pcap_keys->pcap, PCAP_IRQ_ONOFF),
+				   NULL, pcap_keys_handler, 0,
+				   "Power key", pcap_keys);
 	if (err)
 		goto fail_register;
 
-	err = request_irq(pcap_to_irq(pcap_keys->pcap, PCAP_IRQ_MIC),
-			pcap_keys_handler, 0, "Headphone button", pcap_keys);
+	err = request_threaded_irq(pcap_to_irq(pcap_keys->pcap, PCAP_IRQ_MIC),
+				   NULL, pcap_keys_handler, 0,
+				   "Headphone button", pcap_keys);

So I guess we do need threaded IRQ here, but I do not see the pcap's
irqchip specifying IRQCHIP_ONESHOT_SAFE so I do not think
request_threaded_irq() without IRQF_ONESHOT would succeed.

Can someone test the change to be sure?

Tested-by: Antonio Ospite <redacted>

I confirm the keys still work fine with the patch applied on a 3.2
kernel. I cannot test on a newer version for now.

Sorry for the delay.

Ciao ciao,
   Antonio

-- 
Antonio Ospite
http://ao2.it

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?