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ARM: Recover kretprobe modified return address in stacktrace

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Since the kretprobe replaces the function return address with
the kretprobe_trampoline on the stack, arm unwinder shows it
instead of the correct return address.

This finds the correct return address from the per-task
kretprobe_instances list and verify it is in between the
caller fp and callee fp.

Note that this supports both GCC and clang if CONFIG_FRAME_POINTER=y
and CONFIG_ARM_UNWIND=n. For the ARM unwinder, this is still
not working correctly.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu
2021-10-21 09:55:35 +09:00
committed by Steven Rostedt (VMware)
parent 7e9bf33b81
commit fed240d9c9
4 changed files with 28 additions and 0 deletions
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9
arch/arm/include/asm/stacktrace.h
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@@ -3,6 +3,7 @@
#define __ASM_STACKTRACE_H
#include <asm/ptrace.h>
#include <linux/llist.h>
struct stackframe {
/*
@@ -13,6 +14,10 @@ struct stackframe {
unsigned long sp;
unsigned long lr;
unsigned long pc;
#ifdef CONFIG_KRETPROBES
struct llist_node *kr_cur;
struct task_struct *tsk;
#endif
};
static __always_inline
@@ -22,6 +27,10 @@ void arm_get_current_stackframe(struct pt_regs *regs, struct stackframe *frame)
frame->sp = regs->ARM_sp;
frame->lr = regs->ARM_lr;
frame->pc = regs->ARM_pc;
#ifdef CONFIG_KRETPROBES
frame->kr_cur = NULL;
frame->tsk = current;
#endif
}
extern int unwind_frame(struct stackframe *frame);