[PATCH] Input: ipaq-micro-keys - fix potential deadlock

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

The driver acquires the micro->lock spinlock in process context (in
micro_key_start() and micro_key_stop()) without disabling interrupts.
However, this lock is also acquired in hardirq context by the MFD core
rx handler (micro_rx_msg()) which is called from the serial ISR.

This can lead to a lock inversion deadlock if the interrupt fires on the
same CPU while the process context holds the lock.

Fix this by using guard(spinlock_irq) instead of guard(spinlock) in
micro_key_start() and micro_key_stop() to disable interrupts while
holding the lock.

Reported-by: sashiko-bot@kernel.org
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/keyboard/ipaq-micro-keys.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/input/keyboard/ipaq-micro-keys.c b/drivers/input/keyboard/ipaq-micro-keys.c
index ca7ec054b1ce..63d589253e46 100644
--- a/drivers/input/keyboard/ipaq-micro-keys.c
+++ b/drivers/input/keyboard/ipaq-micro-keys.c
@@ -54,7 +54,7 @@ static void micro_key_receive(void *data, int len, unsigned char *msg)
 
 static void micro_key_start(struct ipaq_micro_keys *keys)
 {
-	guard(spinlock)(&keys->micro->lock);
+	guard(spinlock_irq)(&keys->micro->lock);
 
 	keys->micro->key = micro_key_receive;
 	keys->micro->key_data = keys;
@@ -62,7 +62,7 @@ static void micro_key_start(struct ipaq_micro_keys *keys)
 
 static void micro_key_stop(struct ipaq_micro_keys *keys)
 {
-	guard(spinlock)(&keys->micro->lock);
+	guard(spinlock_irq)(&keys->micro->lock);
 
 	keys->micro->key = NULL;
 	keys->micro->key_data = NULL;
-- 
2.54.0.1099.g489fc7bff1-goog


-- 
Dmitry