Patch "csky: patch_text: Fixup last cpu should be master" has been added to the 5.17-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

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

    csky: patch_text: Fixup last cpu should be master

to the 5.17-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:
     csky-patch_text-fixup-last-cpu-should-be-master.patch
and it can be found in the queue-5.17 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 8c4d16471e2babe9bdfe41d6ef724526629696cb Mon Sep 17 00:00:00 2001
From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Date: Wed, 6 Apr 2022 22:28:43 +0800
Subject: csky: patch_text: Fixup last cpu should be master

From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

commit 8c4d16471e2babe9bdfe41d6ef724526629696cb upstream.

These patch_text implementations are using stop_machine_cpuslocked
infrastructure with atomic cpu_count. The original idea: When the
master CPU patch_text, the others should wait for it. But current
implementation is using the first CPU as master, which couldn't
guarantee the remaining CPUs are waiting. This patch changes the
last CPU as the master to solve the potential risk.

Fixes: 33e53ae1ce41 ("csky: Add kprobes supported")
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/csky/kernel/probes/kprobes.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -30,7 +30,7 @@ static int __kprobes patch_text_cb(void
 	struct csky_insn_patch *param = priv;
 	unsigned int addr = (unsigned int)param->addr;
 
-	if (atomic_inc_return(&param->cpu_count) == 1) {
+	if (atomic_inc_return(&param->cpu_count) == num_online_cpus()) {
 		*(u16 *) addr = cpu_to_le16(param->opcode);
 		dcache_wb_range(addr, addr + 2);
 		atomic_inc(&param->cpu_count);


Patches currently in stable-queue which might be from guoren@xxxxxxxxxxxxxxxxx are

queue-5.17/riscv-fixup-difference-with-defconfig.patch
queue-5.17/csky-patch_text-fixup-last-cpu-should-be-master.patch