From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jiri Olsa , Martin Schwidefsky , Sasha Levin Subject: [PATCH AUTOSEL 3.18 06/98] s390/ftrace/jprobes: Fix conflict between jprobes and function graph tracing Date: Thu, 25 Oct 2018 10:17:21 -0400 Message-Id: <20181025141853.214051-6-sashal@kernel.org> In-Reply-To: <20181025141853.214051-1-sashal@kernel.org> References: <20181025141853.214051-1-sashal@kernel.org> List-ID: From: Jiri Olsa [ Upstream commit e64a5470dcd2900ab8f8f83638c00098b10e6300 ] This fixes the same issue Steven already fixed for x86 in following commit: 237d28db036e ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing It fixes the crash, that happens when function graph tracing and jprobes are used simultaneously. Please refer to above commit for details. Signed-off-by: Jiri Olsa Signed-off-by: Martin Schwidefsky Acked-by: Steven Rostedt Signed-off-by: Sasha Levin --- arch/s390/kernel/kprobes.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 014d4729b134..ee03d8f0ee60 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -633,6 +633,15 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) stack = (unsigned long) regs->gprs[15]; memcpy(kcb->jprobes_stack, (void *) stack, MIN_STACK_SIZE(stack)); + + /* + * jprobes use jprobe_return() which skips the normal return + * path of the function, and this messes up the accounting of the + * function graph tracer to get messed up. + * + * Pause function graph tracing while performing the jprobe function. + */ + pause_graph_tracing(); return 1; } @@ -646,6 +655,9 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); unsigned long stack; + /* It's OK to start function graph tracing again */ + unpause_graph_tracing(); + stack = (unsigned long) kcb->jprobe_saved_regs.gprs[15]; /* Put the regs back */ -- 2.17.1