extending BKL in v4l open

PATCH Oliver Neukum 1 participant 1 message Aug 22, 2001

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Oliver Neukum

author

2001-08-22 15:13 UTC #0 lore raw

Hi,

I'd like to propose an extension of code under the BKL in v4l's open method to include the actual open of the low level v4l driver. Otherwise there's a race with usb v4l drivers which deregister themselves as v4l devices upon being disconnected on usb, as the pointer passed may point to freed memory.

Regards
Oliver

videodev.c renamed from videodev.c.alt +4 -3

@@ -164,8 +164,7 @@
 
 	if(vfl->owner)
 		__MOD_INC_USE_COUNT(vfl->owner);
-	unlock_kernel();
-
+
 	if(vfl->open)
 	{
 		err=vfl->open(vfl,0);	/* Tell the device it is open */

@@ -174,10 +173,12 @@
 			vfl->busy=0;
 			if(vfl->owner)
 				__MOD_DEC_USE_COUNT(vfl->owner);
-
+
+			unlock_kernel();
 			return err;
 		}
 	}
+	unlock_kernel();
 	return 0;
 error_out:
 	unlock_kernel();