On Tue, 7 Sep 2010 13:45:34 -0700 Gary King <gking@xxxxxxxxxx> wrote: > I have been seeing problems on Tegra 2 (ARMv7 SMP) systems with HIGHMEM > enabled on 2.6.35 (plus some patches targetted at 2.6.36 to perform > cache maintenance lazily), and the root cause appears to be that the > mm bouncing code is calling flush_dcache_page before it copies the > bounce buffer into the bio. > > The patch below reorders these two operations, and eliminates numerous > arbitrary application crashes on my dev system. > > Gary > > -- > >From 678c9bca8d8a8f254f28af91e69fad3aa1be7593 Mon Sep 17 00:00:00 2001 > From: Gary King <gking@xxxxxxxxxx> > Date: Mon, 6 Sep 2010 15:37:12 -0700 > Subject: bounce: call flush_dcache_page after bounce_copy_vec > > the bounced page needs to be flushed after data is copied into it, > to ensure that architecture implementations can synchronize > instruction and data caches if necessary. > > Signed-off-by: Gary King <gking@xxxxxxxxxx> > --- > mm/bounce.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/mm/bounce.c b/mm/bounce.c > index 13b6dad..1481de6 100644 > --- a/mm/bounce.c > +++ b/mm/bounce.c > @@ -116,8 +116,8 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from) > */ > vfrom = page_address(fromvec->bv_page) + tovec->bv_offset; > > - flush_dcache_page(tovec->bv_page); > bounce_copy_vec(tovec, vfrom); > + flush_dcache_page(tovec->bv_page); > } > } Oh my, that was bad. I queued your fix for 2.6.36 and tagged it for -stable backporting, thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>