From: Steven Rostedt <rostedt@goodmis.org>
To: Jiri Olsa <jolsa@kernel.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Michael Grundy <grundym@us.ibm.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Subject: Re: [PATCH] ftrace/jprobes/s390: Fix conflict between jprobes and function graph tracing
Date: Thu, 28 Jul 2016 14:39:33 -0400 [thread overview]
Message-ID: <20160728143933.1a2abc97@gandalf.local.home> (raw)
In-Reply-To: <1468848401-8091-1-git-send-email-jolsa@kernel.org>
On Mon, 18 Jul 2016 15:26:41 +0200
Jiri Olsa <jolsa@kernel.org> wrote:
> 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.
I'm guessing that this should go in via the s390 tree.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
-- Steve
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> 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 250f5972536a..dd6306c51bd6 100644
> --- a/arch/s390/kernel/kprobes.c
> +++ b/arch/s390/kernel/kprobes.c
> @@ -690,6 +690,15 @@ int 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;
> }
> NOKPROBE_SYMBOL(setjmp_pre_handler);
> @@ -705,6 +714,9 @@ int 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 */
next prev parent reply other threads:[~2016-07-28 18:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-18 13:26 [PATCH] ftrace/jprobes/s390: Fix conflict between jprobes and function graph tracing Jiri Olsa
2016-07-28 18:39 ` Steven Rostedt [this message]
2016-07-31 12:21 ` Jiri Olsa
2016-07-31 13:25 ` Martin Schwidefsky
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