When aborting PS/2 command the kernel should [re]set all flags before
waking up waiters, otherwise waiting thread may read obsolete values
of flags.
Reported-by: Raul Rangel <rrangel@xxxxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
drivers/input/serio/libps2.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
index 14b70a78875d..09eb605364bb 100644
--- a/drivers/input/serio/libps2.c
+++ b/drivers/input/serio/libps2.c
@@ -478,15 +478,22 @@ bool ps2_handle_response(struct ps2dev *ps2dev, u8 data)
}
EXPORT_SYMBOL(ps2_handle_response);
+/*
+ * Clears state of PS/2 device after communication error by resetting majority
+ * of flags and waking up waiters, if any.
+ */
void ps2_cmd_aborted(struct ps2dev *ps2dev)
{
- if (ps2dev->flags & PS2_FLAG_ACK)
+ unsigned long old_flags = ps2dev->flags;
+
+ /* reset all flags except last nak */
+ ps2dev->flags &= PS2_FLAG_NAK;
+
+ if (old_flags & PS2_FLAG_ACK)
ps2dev->nak = 1;
- if (ps2dev->flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
+ if (old_flags & (PS2_FLAG_ACK | PS2_FLAG_CMD))
wake_up(&ps2dev->wait);
- /* reset all flags except last nack */
- ps2dev->flags &= PS2_FLAG_NAK;
}
EXPORT_SYMBOL(ps2_cmd_aborted);
--
2.40.1.606.ga4b1b128d6-goog
