[PATCH] src/nsexec: fix stack pointer alignment exception

From: Zorro Lang <zlang@redhat.com>
To: fstests@vger.kernel.org
Cc: sandeen@redhat.com
Subject: [PATCH] src/nsexec: fix stack pointer alignment exception
Date: Wed, 27 Sep 2017 13:52:52 +0800	[thread overview]
Message-ID: <20170927055252.12225-1-zlang@redhat.com> (raw)

When test g/317 or g/318 on ARM server, we got a kernel exception:

  kernel: nsexec[8203]: SP Alignment exception: pc=00000000004010a0 sp=00000000005200e8

nsexec gives an unaligned child stack address to clone() system
call sometimes. For making sure it's always aligned, use
"__attribute__((aligned))" extension of GCC (Thanks this suggestion
from Eric sandeen).

Signed-off-by: Zorro Lang <zlang@redhat.com>
---
 src/nsexec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/nsexec.c b/src/nsexec.c
index f033b1a4..205dd081 100644
--- a/src/nsexec.c
+++ b/src/nsexec.c
@@ -138,7 +138,8 @@ childFunc(void *arg)
 
 #define STACK_SIZE (1024 * 1024)
 
-static char child_stack[STACK_SIZE];    /* Space for child's stack */
+/* Space for child's stack */
+static char __attribute__((aligned)) child_stack[STACK_SIZE];
 
 int
 main(int argc, char *argv[])
-- 
2.13.5

