| From 5289f46b9de04bde181d833d48df9671b69c4b08 Mon Sep 17 00:00:00 2001 |
| From: Kyle McMartin <kyle@infradead.org> |
| Date: Tue, 23 Dec 2008 08:44:30 -0500 |
| Subject: parisc: disable UP-optimized flush_tlb_mm |
| |
| From: Kyle McMartin <kyle@infradead.org> |
| |
| commit 5289f46b9de04bde181d833d48df9671b69c4b08 upstream. |
| |
| flush_tlb_mm's "optimized" uniprocessor case of allocating a new |
| context for userspace is exposing a race where we can suddely return |
| to a syscall with the protection id and space id out of sync, trapping |
| on the next userspace access. |
| |
| Debugged-by: James Bottomley <James.Bottomley@HansenPartnership.com> |
| Tested-by: Helge Deller <deller@gmx.de> |
| Signed-off-by: Kyle McMartin <kyle@mcmartin.ca> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| include/asm-parisc/tlbflush.h | 5 ++++- |
| 1 file changed, 4 insertions(+), 1 deletion(-) |
| |
| --- a/include/asm-parisc/tlbflush.h |
| +++ b/include/asm-parisc/tlbflush.h |
| @@ -44,9 +44,12 @@ static inline void flush_tlb_mm(struct m |
| { |
| BUG_ON(mm == &init_mm); /* Should never happen */ |
| |
| -#ifdef CONFIG_SMP |
| +#if 1 || defined(CONFIG_SMP) |
| flush_tlb_all(); |
| #else |
| + /* FIXME: currently broken, causing space id and protection ids |
| + * to go out of sync, resulting in faults on userspace accesses. |
| + */ |
| if (mm) { |
| if (mm->context != 0) |
| free_sid(mm->context); |
