lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 23 May 2022 12:35:20 +0000 From: "Starke, Daniel" <daniel.starke@...mens.com> To: Jiri Slaby <jirislaby@...nel.org>, "linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>, "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org> CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: RE: [PATCH v2 4/9] tty: n_gsm: fix missing timer to handle stalled links > > From: Daniel Starke <daniel.starke@...mens.com> > > > > The current implementation does not handle the situation that no data > > is in the internal queue and needs to be sent out while the user tty > > fifo is full. > > Add a timer that moves more data from user tty down to the internal > > queue which is then serialized on the ldisc. This timer is triggered > > if no data was moved from a user tty to the internal queue within 10 * T1. > > > > Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") > > Cc: stable@...r.kernel.org > > Signed-off-by: Daniel Starke <daniel.starke@...mens.com> > > --- > > drivers/tty/n_gsm.c | 43 +++++++++++++++++++++++++++++++++++-------- > > 1 file changed, 35 insertions(+), 8 deletions(-) > > > > See patch 6 regarding changes since to v1. > > > > diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index > > 0a9924445968..3a4a2394d970 100644 > > --- a/drivers/tty/n_gsm.c > > +++ b/drivers/tty/n_gsm.c > ... > > @@ -833,6 +834,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg) > > list_add_tail(&msg->list, &gsm->tx_list); > > gsm->tx_bytes += msg->len; > > gsm_data_kick(gsm, dlci); > > + mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100); > > The formula deserves an explanation. And why 10 * X / 100, and not X / 10? T1 is defined as 1/100th of a second (see chapter 5.7.1 of the standard). Therefore, it is gsm->t1 * HZ / 100. I chose 10x T1 as this case should usually not occur and only acts as a final countermeasure against a stalled link. Or are there any other suggestions for a proper kick timer value? > > @@ -1062,9 +1058,9 @@ static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, > > * renegotiate DLCI priorities with optional stuff. Needs optimising. > > */ > > > > -static void gsm_dlci_data_sweep(struct gsm_mux *gsm) > > +static int gsm_dlci_data_sweep(struct gsm_mux *gsm) > > { > > - int len; > > + int len, ret = 0; > > Why is ret signed? Many obviously only unsigned values are signed in the code of the original author. I simply aligned my code to this to believe that int is preferred. But I can change it to unsigned int if this is preferred here? Best regards, Daniel Starke
Powered by blists - more mailing lists