[PATCH] s390: kernel stack corruption

When an asynchronous interruption occurs during the execution of the
'critical section' within the generic interruption handling code (entry.S),
a faulty check for a userspace PSW may result in a corrupted kernel stack
pointer which subsequently triggers a stack overflow check.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 58fc7fbcb40e..9b30f4cf32c4 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -108,7 +108,7 @@ STACK_SIZE  = 1 << STACK_SHIFT
         bl      BASED(0f)
         l       %r14,BASED(.Lcleanup_critical)
         basr    %r14,%r14
-        tm      0(%r12),0x01            # retest problem state after cleanup
+        tm      1(%r12),0x01            # retest problem state after cleanup
         bnz     BASED(1f)
 0:      l       %r14,__LC_ASYNC_STACK   # are we already on the async stack ?
         slr     %r14,%r15
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index d0c9ffaa25db..7b9b4a2ba1d7 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -101,7 +101,7 @@ _TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
         clc     \psworg+8(8),BASED(.Lcritical_start)
         jl      0f
         brasl   %r14,cleanup_critical
-        tm      0(%r12),0x01            # retest problem state after cleanup
+        tm      1(%r12),0x01            # retest problem state after cleanup
         jnz     1f
 0:      lg      %r14,__LC_ASYNC_STACK   # are we already on the async. stack ?
         slgr    %r14,%r15