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@xxxxxxxxxxxxxxxxxxxxx>
Tested-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Kyle McMartin <kyle@xxxxxxxxxxx>
---
Linus, Greg, please apply to stable and HEAD, this is a fairly
important fix for parisc.
Thanks,
Kyle
arch/parisc/include/asm/tlbflush.h | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/arch/parisc/include/asm/tlbflush.h b/arch/parisc/include/asm/tlbflush.h
index b72ec66..1f6fd4f 100644
--- a/arch/parisc/include/asm/tlbflush.h
+++ b/arch/parisc/include/asm/tlbflush.h
@@ -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);
--
1.6.0.4
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