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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org>
Cc: x86@kernel.org, Masami Hiramatsu <mhiramat@kernel.org>,
	Yang Bo <yangbo@deepin.com>, Ingo Molnar <mingo@redhat.com>,
	"H . Peter Anvin" <hpa@zytor.com>,
	linux-kernel@vger.kernel.org,
	Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Laura Abbott <labbott@redhat.com>, Josef Bacik <jbacik@fb.com>,
	Alexei Starovoitov <ast@kernel.org>
Subject: [RFC PATCH -tip 9/9] tracing: kprobes: Fix to not enabling preemption
Date: Fri,  9 Mar 2018 21:39:45 +0900	[thread overview]
Message-ID: <152059918532.4214.8326814684091028387.stgit@devbox> (raw)
In-Reply-To: <152059891712.4214.9539716544254881611.stgit@devbox>

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@kernel.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)

  parent reply	other threads:[~2018-03-09 12:40 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-09 12:35 [RFC PATCH -tip 0/9] kprobes: Cleanup jprobe implementation Masami Hiramatsu
2018-03-09 12:35 ` [RFC PATCH -tip 1/9] kprobes: Remove jprobe API implementation Masami Hiramatsu
2018-03-09 12:36 ` [RFC PATCH -tip 2/9] x86: kprobes: Remove jprobe implementation Masami Hiramatsu
2018-03-09 12:36 ` [RFC PATCH -tip 3/9] kprobes: Remove jprobe data structure and interfaces Masami Hiramatsu
2018-03-09 12:37 ` [RFC PATCH -tip 4/9] kprobes: Ignore break_handler Masami Hiramatsu
2018-03-09 12:37 ` [RFC PATCH -tip 5/9] x86: " Masami Hiramatsu
2018-03-09 12:38 ` [RFC PATCH -tip 6/9] kprobes: Remove break_handler from struct kprobe Masami Hiramatsu
2018-03-09 12:38 ` [RFC PATCH -tip 7/9] x86: kprobes: Do not disable preempt on int3 path Masami Hiramatsu
2018-03-09 12:39 ` [RFC PATCH -tip 8/9] error-injection: Fix to not enabling preemption in pre_handler Masami Hiramatsu
2018-03-10  8:22   ` Ingo Molnar
2018-03-11 15:05     ` Masami Hiramatsu
2018-03-09 12:39 ` Masami Hiramatsu [this message]
2018-03-09 23:54 ` [RFC PATCH -tip 0/9] kprobes: Cleanup jprobe implementation Steven Rostedt
2018-03-10 13:55   ` Masami Hiramatsu
2018-03-10  8:24 ` Ingo Molnar
2018-03-11 15:13   ` Masami Hiramatsu

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