Hi Chris,
On Thu, Aug 19, 2004 at 09:51:34AM -0400, Chris Mason wrote:
On Thu, 2004-08-19 at 07:07, Con Kolivas wrote:
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;
}
}
Hmm, that patch would make a lot of sense to me.
It matches the problem description; burning data CDs, we don't
use bounce buffers, so that does not use this code path. Here,
it looks like we copied the same userspace page again and again
into a multisegment BIO. Ouch!
Not yet tested either :-(
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