This is a note to let you know that I've just added the patch titled
tty: n_gsm: fix DM command
to the 4.9-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:
tty-n_gsm-fix-dm-command.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 01738a739525aa96bd4833b0e71ac01509ad4c95
Author: Daniel Starke <daniel.starke@xxxxxxxxxxx>
Date: Thu Jul 7 13:32:21 2022 +0200
tty: n_gsm: fix DM command
[ Upstream commit 18a948c7d90995d127785e308fa7b701df4c499f ]
n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010.
See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516
The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to
the newer 27.010 here. Chapter 5.3.3 defines the DM response. There exists
no DM command. However, the current implementation incorrectly sends DM as
command in case of unexpected UIH frames in gsm_queue().
Correct this behavior by always sending DM as response.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Signed-off-by: Daniel Starke <daniel.starke@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220707113223.3685-2-daniel.starke@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 7f50f7f15b86..08db25ca4e97 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -1910,7 +1910,7 @@ static void gsm_queue(struct gsm_mux *gsm)
goto invalid;
#endif
if (dlci == NULL || dlci->state != DLCI_OPEN) {
- gsm_command(gsm, address, DM|PF);
+ gsm_response(gsm, address, DM|PF);
return;
}
dlci->data(dlci, gsm->buf, gsm->len);
