Re: [PATCH] bio_uncopy_user mem leak

From: Chris Mason
Date: Thu Aug 19 2004 - 08:51:38 EST


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;
}
}






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