2010-07-29 09:09:55

by Jiri Slaby

Subject: [PATCH 1/1] Char: nozomi, fix tty->count counting

Currently ntty_install omits to increment tty count and we get the
following warnings:
Warning: dev (noz2) tty->count(0) != #fd's(1) in tty_open

So to fix that, add one tty->count++ there.

Signed-off-by: Jiri Slaby <[email protected]>
Cc: Alan Cox <[email protected]>
---
drivers/char/nozomi.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/char/nozomi.c b/drivers/char/nozomi.c
index d578449..7f9b858 100644
--- a/drivers/char/nozomi.c
+++ b/drivers/char/nozomi.c
@@ -1611,6 +1611,7 @@ static int ntty_install(struct tty_driver *driver, struct tty_struct *tty)
ret = tty_init_termios(tty);
if (ret == 0) {
tty_driver_kref_get(driver);
+ tty->count++;
driver->ttys[tty->index] = tty;
}
return ret;
--
1.7.2

2010-07-29 09:13:57

by Jiri Slaby

Subject: Re: [PATCH 1/1] Char: nozomi, fix tty->count counting

On 07/29/2010 11:09 AM, Jiri Slaby wrote:
> Currently ntty_install omits to increment tty count and we get the
> following warnings:
> Warning: dev (noz2) tty->count(0) != #fd's(1) in tty_open
>
> So to fix that, add one tty->count++ there.
>
> Signed-off-by: Jiri Slaby <[email protected]>
> Cc: Alan Cox <[email protected]>

BTW introduced in 266794eb7 (nozomi: Add tty_port usage) which is in
.34. So may be a stable material too...

> ---
> drivers/char/nozomi.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/char/nozomi.c b/drivers/char/nozomi.c
> index d578449..7f9b858 100644
> --- a/drivers/char/nozomi.c
> +++ b/drivers/char/nozomi.c
> @@ -1611,6 +1611,7 @@ static int ntty_install(struct tty_driver *driver, struct tty_struct *tty)
> ret = tty_init_termios(tty);
> if (ret == 0) {
> tty_driver_kref_get(driver);
> + tty->count++;
> driver->ttys[tty->index] = tty;
> }
> return ret;

thanks,
--
js

2010-07-29 09:46:41

by Jiri Slaby

Subject: [PATCH 1/1] Char: nozomi, set tty->driver_data appropriately

Sorry, one more fix, this one depends on the other, so this is rather 2/2.
--

tty->driver_data is used all over the code, but never set. This
results in oopses like:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000130
IP: [<ffffffff814a0040>] mutex_lock+0x10/0x40
...
Pid: 2157, comm: modem-manager Not tainted 2.6.34.1-0.1-desktop #1 2768DR7/2768DR7
RIP: 0010:[<ffffffff814a0040>] [<ffffffff814a0040>] mutex_lock+0x10/0x40
RSP: 0018:ffff88007b16fa50 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000130 RCX: 0000000000000003
RDX: 0000000000000003 RSI: 0000000000000286 RDI: 0000000000000130
RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000130
R13: 0000000000000001 R14: 0000000000000000 R15: ffff88007b16feb4
...
Call Trace:
[<ffffffffa077690d>] ntty_write_room+0x4d/0x90 [nozomi]
...

Set tty->driver_data to the computed port in .install to not recompute it in
every place where needed. Switch .open to use driver_data too.

Signed-off-by: Jiri Slaby <[email protected]>
Cc: Alan Cox <[email protected]>
---
drivers/char/nozomi.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/char/nozomi.c b/drivers/char/nozomi.c
index 7f9b858..817169c 100644
--- a/drivers/char/nozomi.c
+++ b/drivers/char/nozomi.c
@@ -1612,6 +1612,7 @@ static int ntty_install(struct tty_driver *driver, struct tty_struct *tty)
if (ret == 0) {
tty_driver_kref_get(driver);
tty->count++;
+ tty->driver_data = port;
driver->ttys[tty->index] = tty;
}
return ret;
@@ -1640,7 +1641,7 @@ static int ntty_activate(struct tty_port *tport, struct tty_struct *tty)

static int ntty_open(struct tty_struct *tty, struct file *filp)
{
- struct port *port = get_port_by_tty(tty);
+ struct port *port = tty->driver_data;
return tty_port_open(&port->port, tty, filp);
}

--
1.7.2