Patch "arm64/ptrace: Preserve previous registers for short regset write" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

arm64/ptrace: Preserve previous registers for short regset write

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
arm64-ptrace-preserve-previous-registers-for-short-regset-write.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dave Martin <[email protected]>
Date: Wed, 18 Jan 2017 16:25:20 +0000
Subject: arm64/ptrace: Preserve previous registers for short regset write

From: Dave Martin <[email protected]>

commit 9a17b876b573441bfb3387ad55d98bf7184daf9d upstream.

Ensure that if userspace supplies insufficient data to PTRACE_SETREGSET to fill all the registers, the thread's old registers are preserved.

---
 arch/arm64/kernel/ptrace.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

@@ -495,7 +495,7 @@ static int gpr_set(struct task_struct *t
 		   const void *kbuf, const void __user *ubuf)
 {
 	int ret;
-	struct user_pt_regs newregs;
+	struct user_pt_regs newregs = task_pt_regs(target)->user_regs;
 
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
 	if (ret)

@@ -525,7 +525,8 @@ static int fpr_set(struct task_struct *t
 		   const void *kbuf, const void __user *ubuf)
 {
 	int ret;
-	struct user_fpsimd_state newstate;
+	struct user_fpsimd_state newstate =
+		target->thread.fpsimd_state.user_fpsimd;
 
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
 	if (ret)

@@ -549,7 +550,7 @@ static int tls_set(struct task_struct *t
 		   const void *kbuf, const void __user *ubuf)
 {
 	int ret;
-	unsigned long tls;
+	unsigned long tls = target->thread.tp_value;
 
 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
 	if (ret)

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/arm64-ptrace-preserve-previous-registers-for-short-regset-write-3.patch queue-4.4/arm64-ptrace-reject-attempts-to-set-incomplete-hardware-breakpoint-fields.patch queue-4.4/arm64-ptrace-preserve-previous-registers-for-short-regset-write-2.patch queue-4.4/arm64-ptrace-avoid-uninitialised-struct-padding-in-fpr_set.patch queue-4.4/arm64-ptrace-preserve-previous-registers-for-short-regset-write.patch