From: Daniel Starke daniel.starke@siemens.com
stable inclusion from stable-v5.10.137 commit 01c8094bed8e05a9e70e6df81c3f0db732d23308 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ 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.a... 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@siemens.com Link: https://lore.kernel.org/r/20220707113223.3685-2-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- drivers/tty/n_gsm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 3f100f7abdb7..a6c0a1b76ddb 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1938,7 +1938,7 @@ 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);