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parisc: disable UP-optimized flush_tlb_mm

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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>
This commit is contained in:
Kyle McMartin 2008-12-23 08:44:30 -05:00 committed by Linus Torvalds
parent 8960223d59
commit 5289f46b9d
1 changed files with 4 additions and 1 deletions
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5
arch/parisc/include/asm/tlbflush.h
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@ -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);