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Input: libps2 - fix aborting PS/2 commands

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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@chromium.org>
Reviewed-by: Raul E Rangel <rrangel@chromium.org>
Link: https://lore.kernel.org/r/20230511185252.386941-6-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov
2023-05-11 11:52:45 -07:00
parent 1db0fd245b
commit 7d674f9150
1 changed files with 11 additions and 4 deletions
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drivers/input/serio/libps2.c
+11 -4
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@@ -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);