Patch "kprobes/x86: Fix kprobe-booster not to boost far call instructions" 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

kprobes/x86: Fix kprobe-booster not to boost far call instructions

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:
kprobes-x86-fix-kprobe-booster-not-to-boost-far-call-instructions.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: Masami Hiramatsu <[email protected]>
Date: Wed, 29 Mar 2017 13:56:56 +0900
Subject: kprobes/x86: Fix kprobe-booster not to boost far call instructions

From: Masami Hiramatsu <[email protected]>

[ Upstream commit bd0b90676c30fe640e7ead919b3e38846ac88ab7 ]

Fix the kprobe-booster not to boost far call instruction, because a call may store the address in the single-step execution buffer to the stack, which should be modified after single stepping.

Currently, this instruction will be filtered as not boostable in resume_execution(), so this is not a critical issue.

---
 arch/x86/kernel/kprobes/core.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -196,6 +196,8 @@ retry:
 		return (opcode != 0x62 && opcode != 0x67);
 	case 0x70:
 		return 0; /* can't boost conditional jump */
+	case 0x90:
+		return opcode != 0x9a;	/* can't boost call far */
 	case 0xc0:
 		/* can't boost software-interruptions */
 		return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;

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

queue-4.4/perf-session-don-t-rely-on-evlist-in-pipe-mode.patch queue-4.4/kprobes-x86-set-kprobes-pages-read-only.patch queue-4.4/kprobes-x86-fix-kprobe-booster-not-to-boost-far-call-instructions.patch queue-4.4/perf-inject-copy-events-when-reordering-events-in-pipe-mode.patch queue-4.4/perf-probe-return-errno-when-not-hitting-any-event.patch