On 02/29/2016 09:24 AM, David Hildenbrand wrote: >> On 02/27/2016 03:28 PM, John Paul Adrian Glaubitz wrote: >>> Hi Hans! >>> >>> On 02/27/2016 03:20 PM, Geert Uytterhoeven wrote: >>>>> I noticed that 4.1 was ok and v4.2 wasn't, so I did a git bisect and ended up with >>>>> commit 8222dbe21e79338de92d5e1956cd1e3994cc9f93 (sched/preempt, mm/fault: Decouple >>>>> preemption from the page fault logic) as the culprit. >>> >>> If you like, please report this the kernel bug tracker and set >>> "Hardware" to "SuperH". This way we are able to keep track of >>> the issue. >>> >>> I think Yoshinori Sato and Rich Felker will have a look at this. >>> >>> Adrian >>> >> >> Done: https://bugzilla.kernel.org/show_bug.cgi?id=113321 >> >> Regards, >> >> Hans >> > > Looks like the code then requires to not be allowed to sleep/preempt in these > sections (just like kmap_atomic, or kmap_coherent on mips). > > So the fix should be simple as (untested): That fixes it for me: Tested-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> BTW, your patch is garbled and I had to manually make the change (not a big deal for a simple change like this). Thanks! Hans > > From d29f0d0cb670175c688cdd181c7a693d28b27a33 Mon Sep 17 00:00:00 2001 > From: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx> > Date: Mon, 29 Feb 2016 09:19:24 +0100 > Subject: [PATCH] sched/preempt, sh: kmap_coherent relies on disabled > preemption > > kmap_coherent needs disabled preemption to not schedule in the critical > section, just like kmap_coherent on mips and kmap_atomic in general. > > Fixes: 8222dbe21e79 "sched/preempt, mm/fault: Decouple preemption from the page fault logic" > Reported-by: Hans Verkuil <hverkuil@xxxxxxxxx> > Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx> > --- > arch/sh/mm/kmap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/sh/mm/kmap.c b/arch/sh/mm/kmap.c > index ec29e14..bf25d7c 100644 > --- a/arch/sh/mm/kmap.c > +++ b/arch/sh/mm/kmap.c > @@ -36,6 +36,7 @@ void *kmap_coherent(struct page *page, unsigned long addr) > > BUG_ON(!test_bit(PG_dcache_clean, &page->flags)); > > + preempt_disable(); > pagefault_disable(); > > idx = FIX_CMAP_END - > @@ -64,4 +65,5 @@ void kunmap_coherent(void *kvaddr) > } > > pagefault_enable(); > + preempt_enable(); > } > -- > 2.3.9 > > > David >
