From 35de3b1aa16842214e0cd7c6036daf4619294314 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 8 Dec 2015 13:50:56 -0500 Subject: [PATCH] powerpc: Implement save_stack_trace_regs() to enable kprobe stack tracing It has come to my attention that kprobe event stack tracing does not work on powerpc. You can see with the following: # cd /sys/kernel/debug/tracing # echo stacktrace > trace_options # echo 'p kfree' > kprobe_events # echo 1 > events/kprobes/enable Will print the following warning: save_stack_trace_regs() not implemented yet. Although save_stack_trace() (which normal event stack traces use) is implemented, save_stack_trace_regs() which kprobe events use is not. This is a cheap attempt to implement that function. Note, This may have issues if a task tries to get a stack trace from another task with its regs, because it just passes in "current" to save_context_stack(). But this does solve the issue with stack tracing kprobe events. Reported-by: Chunyu Hu Signed-off-by: Steven Rostedt Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/stacktrace.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c index ea43a347a104..4f24606afc3f 100644 --- a/arch/powerpc/kernel/stacktrace.c +++ b/arch/powerpc/kernel/stacktrace.c @@ -61,3 +61,10 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) save_context_stack(trace, tsk->thread.ksp, tsk, 0); } EXPORT_SYMBOL_GPL(save_stack_trace_tsk); + +void +save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) +{ + save_context_stack(trace, regs->gpr[1], current, 0); +} +EXPORT_SYMBOL_GPL(save_stack_trace_regs); -- 2.20.1