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authorPete Zaitcev <zaitcev@redhat.com>2008-03-05 02:28:42 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2008-03-10 19:42:25 -0400
commitb507cc9710d8b6e3013468b40522e235342fc84a (patch)
tree9543c5e06c1d1fb6890d2520b876bf9828c367a6 /drivers/usb
parentcdeeeae056a429e729ae9e914fa8142ee45bee93 (diff)
USB: fix usb-serial generic recursive lock
Nobody should be using the generic usb-serial for anything other than testing. Still, it's not a good thing that it's easy to lock up. There is a traceback from NMI oopser here: https://bugzilla.redhat.com/show_bug.cgi?id=431379 But in short, if a line discipline has a chance to echo anything, input can loop back a write method. So, don't call tty_flip_buffer_push from under a lock taken on write path. Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/serial/generic.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 97fa3c428435..7cfce9dabb90 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -323,7 +323,7 @@ static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
323 room = tty_buffer_request_room(tty, urb->actual_length); 323 room = tty_buffer_request_room(tty, urb->actual_length);
324 if (room) { 324 if (room) {
325 tty_insert_flip_string(tty, urb->transfer_buffer, room); 325 tty_insert_flip_string(tty, urb->transfer_buffer, room);
326 tty_flip_buffer_push(tty); /* is this allowed from an URB callback ? */ 326 tty_flip_buffer_push(tty);
327 } 327 }
328 } 328 }
329 329
@@ -349,10 +349,12 @@ void usb_serial_generic_read_bulk_callback (struct urb *urb)
349 349
350 /* Throttle the device if requested by tty */ 350 /* Throttle the device if requested by tty */
351 spin_lock_irqsave(&port->lock, flags); 351 spin_lock_irqsave(&port->lock, flags);
352 if (!(port->throttled = port->throttle_req)) 352 if (!(port->throttled = port->throttle_req)) {
353 /* Handle data and continue reading from device */ 353 spin_unlock_irqrestore(&port->lock, flags);
354 flush_and_resubmit_read_urb(port); 354 flush_and_resubmit_read_urb(port);
355 spin_unlock_irqrestore(&port->lock, flags); 355 } else {
356 spin_unlock_irqrestore(&port->lock, flags);
357 }
356} 358}
357EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback); 359EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
358 360