Re: [PATCH] bio_uncopy_user mem leak

[Chris Mason <mason@suse.com>]

On Thu, 2004-08-19 at 07:07, Con Kolivas wrote:
> Greg Afinogenov wrote:
> > I'd just like to point out that this patch does not, as may be expected,
> > result in functional audio CDs.  It merely results in a successful burn
> > process and a CD full of noise.
> > 
> > Perhaps this should be tested/fixed?
> 
> Ok I just tested this patch discretely and indeed the memory leak goes 
> away but it still produces coasters so something is still amuck. Just as 
> a data point; burning DVDs and data cds is ok. Burning audio *and 
> videocds* is not.

It might be the cold medicine talking, but I think we need something
like this.  gcc tested it for me, beyond that I make no promises....

--- l/fs/bio.c.1	2004-08-19 09:36:13.596858736 -0400
+++ l/fs/bio.c	2004-08-19 09:47:46.392537784 -0400
@@ -454,6 +454,7 @@
 	 */
 	if (!ret) {
 		if (!write_to_vm) {
+			unsigned long p = uaddr;
 			bio->bi_rw |= (1 << BIO_RW);
 			/*
 	 		 * for a write, copy in data to kernel pages
@@ -462,8 +463,9 @@
 			bio_for_each_segment(bvec, bio, i) {
 				char *addr = page_address(bvec->bv_page);
 
-				if (copy_from_user(addr, (char *) uaddr, bvec->bv_len))
+				if (copy_from_user(addr, (char *) p, bvec->bv_len))
 					goto cleanup;
+				p += bvec->bv_len;
 			}
 		}