Patch "MIPS: uprobes: remove incorrect set_orig_insn" 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

MIPS: uprobes: remove incorrect set_orig_insn

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:
mips-uprobes-remove-incorrect-set_orig_insn.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: Marcin Nowakowski <[email protected]>
Date: Thu, 22 Sep 2016 15:38:32 +0200
Subject: MIPS: uprobes: remove incorrect set_orig_insn

From: Marcin Nowakowski <[email protected]>

commit ddabfa5c2e33f1b495f3e0176de7057850915c0b upstream.

Generic kernel code implements a weak version of set_orig_insn that moves cached 'insn' from arch_uprobe to the original code location when the trap is removed.
MIPS variant used arch_uprobe->orig_inst which was never initialised properly, so this code only inserted a nop instead of the original instruction. With that change orig_inst can also be safely removed.

Patchwork: https://patchwork.linux-mips.org/patch/14299/

---
 arch/mips/include/asm/uprobes.h |    1 -
 arch/mips/kernel/uprobes.c      |   18 ------------------
 2 files changed, 19 deletions(-)

@@ -36,7 +36,6 @@ struct arch_uprobe {
 	unsigned long	resume_epc;
 	u32	insn[2];
 	u32	ixol[2];
-	union	mips_instruction orig_inst[MAX_UINSN_BYTES / 4];
 };
 
 struct arch_uprobe_task {

@@ -280,24 +280,6 @@ int __weak set_swbp(struct arch_uprobe *
 	return uprobe_write_opcode(mm, vaddr, UPROBE_SWBP_INSN);
 }
 
-/**
- * set_orig_insn - Restore the original instruction.
- * @mm: the probed process address space.
- * @auprobe: arch specific probepoint information.
- * @vaddr: the virtual address to insert the opcode.
- *
- * For mm @mm, restore the original opcode (opcode) at @vaddr.
- * Return 0 (success) or a negative errno.
- *
- * This overrides the weak version in kernel/events/uprobes.c.
- */
-int set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
-		 unsigned long vaddr)
-{
-	return uprobe_write_opcode(mm, vaddr,
-			*(uprobe_opcode_t *)&auprobe->orig_inst[0].word);
-}
-
 void __weak arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
 				  void *src, unsigned long len)
 {

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

queue-4.4/mips-uprobes-fix-use-of-uninitialised-variable.patch queue-4.4/mips-fix-uretprobe-implementation.patch queue-4.4/mips-uprobes-remove-incorrect-set_orig_insn.patch