This is a note to let you know that I've just added the patch titled HID: multitouch: Add memory barriers to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hid-multitouch-add-memory-barriers.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From be6e2b5734a425941fcdcdbd2a9337be498ce2cf Mon Sep 17 00:00:00 2001 From: Andri Yngvason <andri@xxxxxxxxxxx> Date: Wed, 7 Sep 2022 15:01:59 +0000 Subject: HID: multitouch: Add memory barriers From: Andri Yngvason <andri@xxxxxxxxxxx> commit be6e2b5734a425941fcdcdbd2a9337be498ce2cf upstream. This fixes broken atomic checks which cause a race between the release-timer and processing of hid input. I noticed that contacts were sometimes sticking, even with the "sticky fingers" quirk enabled. This fixes that problem. Cc: stable@xxxxxxxxxxxxxxx Fixes: 9609827458c3 ("HID: multitouch: optimize the sticky fingers timer") Signed-off-by: Andri Yngvason <andri@xxxxxxxxxxx> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220907150159.2285460-1-andri@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hid/hid-multitouch.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -1154,7 +1154,7 @@ static void mt_touch_report(struct hid_d int contact_count = -1; /* sticky fingers release in progress, abort */ - if (test_and_set_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags)) + if (test_and_set_bit_lock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags)) return; scantime = *app->scantime; @@ -1235,7 +1235,7 @@ static void mt_touch_report(struct hid_d del_timer(&td->release_timer); } - clear_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags); + clear_bit_unlock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags); } static int mt_touch_input_configured(struct hid_device *hdev, @@ -1672,11 +1672,11 @@ static void mt_expired_timeout(struct ti * An input report came in just before we release the sticky fingers, * it will take care of the sticky fingers. */ - if (test_and_set_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags)) + if (test_and_set_bit_lock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags)) return; if (test_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags)) mt_release_contacts(hdev); - clear_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags); + clear_bit_unlock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags); } static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id) Patches currently in stable-queue which might be from andri@xxxxxxxxxxx are queue-4.19/hid-multitouch-add-memory-barriers.patch