Commit 5289f46b authored Dec 23, 2008 by Kyle McMartin Committed by Linus Torvalds Dec 23, 2008

parisc: disable UP-optimized flush_tlb_mm



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>

parent 8960223d

arch/parisc/include/asm/tlbflush.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -44,9 +44,12 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
		{
		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);