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authorSteven Rostedt <rostedt@goodmis.org>2015-12-08 19:50:56 +0100
committerMichael Ellerman <mpe@ellerman.id.au>2016-01-11 04:27:28 +0100
commit35de3b1aa16842214e0cd7c6036daf4619294314 (patch)
tree4a3718c699c1d85e56d27e7cd3af06c9f62cb1ee /arch
parentpowerpc: Fix build break due to paca mm_context_t changes (diff)
downloadlinux-35de3b1aa16842214e0cd7c6036daf4619294314.tar.xz
linux-35de3b1aa16842214e0cd7c6036daf4619294314.zip
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 <chuhu@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/stacktrace.c7
1 files changed, 7 insertions, 0 deletions
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);