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Message-Id: <152059918532.4214.8326814684091028387.stgit@devbox>
Date: Fri, 9 Mar 2018 21:39:45 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...nel.org>
Cc: x86@...nel.org, Masami Hiramatsu <mhiramat@...nel.org>,
Yang Bo <yangbo@...pin.com>, Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Steven Rostedt <rostedt@...dmis.org>,
Laura Abbott <labbott@...hat.com>, Josef Bacik <jbacik@...com>,
Alexei Starovoitov <ast@...nel.org>
Subject: [RFC PATCH -tip 9/9] tracing: kprobes: Fix to not enabling preemption
Since kprobes pre_handler doesn't need to recover preemption
even if it modifies regs->ip anymore, this fixes to remove
the preempt_enable_no_resched() from pre_handler.
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
kernel/trace/trace_kprobe.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 5ce9b8cf7be3..6c894e2be8d6 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1221,12 +1221,9 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
* We need to check and see if we modified the pc of the
* pt_regs, and if so clear the kprobe and return 1 so that we
* don't do the single stepping.
- * The ftrace kprobe handler leaves it up to us to re-enable
- * preemption here before returning if we've modified the ip.
*/
if (orig_ip != instruction_pointer(regs)) {
reset_current_kprobe();
- preempt_enable_no_resched();
return 1;
}
if (!ret)
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