4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dave Martin <dave.mar...@arm.com>
commit 9dd73f72f218320c6c90da5f834996e7360dc227 upstream.
Ensure that if userspace supplies insufficient data to
PTRACE_SETREGSET to fill all the registers, the thread's old
registers are preserved.
Fixes: 766a85d7bc5d ("arm64: ptrace: add NT_ARM_SYSTEM_CALL regset")
Signed-off-by: Dave Martin <dave.mar...@arm.com>
Acked-by: Will Deacon <will.dea...@arm.com>
Signed-off-by: Catalin Marinas <catalin.mari...@arm.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/arm64/kernel/ptrace.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -576,7 +576,8 @@ static int system_call_set(struct task_s
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
- int syscallno, ret;
+ int syscallno = task_pt_regs(target)->syscallno;
+ int ret;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1);
if (ret)
