Commit 7d674f91 authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: libps2 - fix aborting PS/2 commands 



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: default avatarRaul Rangel <rrangel@chromium.org>
Reviewed-by: default avatarRaul E Rangel <rrangel@chromium.org>
Link: https://lore.kernel.org/r/20230511185252.386941-6-dmitry.torokhov@gmail.com


Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 1db0fd24

drivers/input/serio/libps2.c

+11 −4
Original line number Diff line number Diff line
@@ -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);