From: Masami Hiramatsu <mhiramat@kernel.org>
Date: Tue, 14 Sep 2021 23:42:02 +0900
Subject: arm: kprobes: Make space for instruction pointer on stack
Git-commit: 7391dd19027cec4e0edf81b7c27079ae0ecd2d6b
Patch-mainline: v5.16-rc1
References: bsc#1193277
Since arm's __kretprobe_trampoline() saves partial 'pt_regs' on the
stack, 'regs->ARM_pc' (instruction pointer) is not accessible from
the kretprobe handler. This means if instruction_pointer_set() is
used from kretprobe handler, it will break the data on the stack.
Make space for instruction pointer (ARM_pc) on the stack in the
__kretprobe_trampoline() for fixing this problem.
Link: https://lkml.kernel.org/r/163163052262.489837.10327621053231461255.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
---
arch/arm/probes/kprobes/core.c | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -376,11 +376,13 @@ int __kprobes kprobe_exceptions_notify(s
void __naked __kprobes __kretprobe_trampoline(void)
{
__asm__ __volatile__ (
+ "sub sp, sp, #16 \n\t"
"stmdb sp!, {r0 - r11} \n\t"
"mov r0, sp \n\t"
"bl trampoline_handler \n\t"
"mov lr, r0 \n\t"
"ldmia sp!, {r0 - r11} \n\t"
+ "add sp, sp, #16 \n\t"
#ifdef CONFIG_THUMB2_KERNEL
"bx lr \n\t"
#else