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

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

[Jiri Slaby]

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 <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
---
 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

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

[Jiri Slaby]

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 <jslaby@suse.cz>
> Cc: Alan Cox <alan@linux.intel.com>

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

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

[Jiri Slaby]

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 <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
---
 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