diff options
| author | Luiz Fernando Capitulino <lcapitulino@mandriva.com.br> | 2005-11-28 19:16:07 -0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2006-01-04 13:48:35 -0800 |
| commit | 8a4613f01f5bb850cab34e3db572d97251d997b3 (patch) | |
| tree | 3ce08f8c75cf8696f7902dd33298a95016ed4e14 /drivers/usb/serial/usb-serial.h | |
| parent | 487f9c6710e7dff338e59820f6cfaeaaa87cb532 (diff) | |
[PATCH] USB: usbserial: race-condition fix.
There is a race-condition in usb-serial driver that can be triggered if
a processes does 'port->tty->driver_data = NULL' in serial_close() while
other processes is in kernel-space about to call serial_ioctl() on the
same port.
This happens because a process can open the device while there is
another one closing it.
The patch below fixes that by adding a semaphore to ensure that no
process will open the device while another process is closing it.
Note that we can't use spinlocks here, since serial_open() and
serial_close() can sleep.
Signed-off-by: Luiz Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/serial/usb-serial.h')
| -rw-r--r-- | drivers/usb/serial/usb-serial.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/serial/usb-serial.h b/drivers/usb/serial/usb-serial.h index 238a5a871ed6..d7d27c3385b3 100644 --- a/drivers/usb/serial/usb-serial.h +++ b/drivers/usb/serial/usb-serial.h @@ -16,6 +16,7 @@ #include <linux/config.h> #include <linux/kref.h> +#include <asm/semaphore.h> #define SERIAL_TTY_MAJOR 188 /* Nice legal number now */ #define SERIAL_TTY_MINORS 255 /* loads of devices :) */ @@ -30,6 +31,8 @@ * @serial: pointer back to the struct usb_serial owner of this port. * @tty: pointer to the corresponding tty for this port. * @lock: spinlock to grab when updating portions of this structure. + * @sem: semaphore used to synchronize serial_open() and serial_close() + * access for this port. * @number: the number of the port (the minor number). * @interrupt_in_buffer: pointer to the interrupt in buffer for this port. * @interrupt_in_urb: pointer to the interrupt in struct urb for this port. @@ -60,6 +63,7 @@ struct usb_serial_port { struct usb_serial * serial; struct tty_struct * tty; spinlock_t lock; + struct semaphore sem; unsigned char number; unsigned char * interrupt_in_buffer; |