From: Heiko Carstens Date: Fri, 11 Oct 2013 06:55:57 +0000 (+0200) Subject: s390/ftrace: prepare_ftrace_return() function call order X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=05e0baaf9ba5a2d173c026530154388f0d2da72c;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git s390/ftrace: prepare_ftrace_return() function call order Steven Rostedt noted that s390 is the only architecture which calls ftrace_push_return_trace() before ftrace_graph_entry() and therefore has the small advantage that trace.depth gets initialized automatically. However this small advantage isn't worth the difference and possible subtle breakage that may result from this. So change s390 to have the same function call order like all other architectures: first ftrace_graph_entry(), then ftrace_push_return_trace() Reported-by: Steven Rostedt Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 1014ad5f7693..224db03e9518 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -151,14 +151,13 @@ unsigned long __kprobes prepare_ftrace_return(unsigned long parent, if (unlikely(atomic_read(¤t->tracing_graph_pause))) goto out; ip = (ip & PSW_ADDR_INSN) - MCOUNT_INSN_SIZE; - if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY) - goto out; trace.func = ip; + trace.depth = current->curr_ret_stack + 1; /* Only trace if the calling function expects to. */ - if (!ftrace_graph_entry(&trace)) { - current->curr_ret_stack--; + if (!ftrace_graph_entry(&trace)) + goto out; + if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY) goto out; - } parent = (unsigned long) return_to_handler; out: return parent;