linux-kernel - [RFT PATCH 02/13] kprobes: Remove redundant arch_disarm

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Message-Id: <157918586979.29301.15267608912757298568.stgit@devnote2>
Date:   Thu, 16 Jan 2020 23:44:30 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Brendan Gregg <brendan.d.gregg@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Alexei Starovoitov <ast@...nel.org>
Cc:     mhiramat@...nel.org, Ingo Molnar <mingo@...nel.org>,
        bpf@...r.kernel.org, linux-kernel@...r.kernel.org,
        Daniel Borkmann <daniel@...earbox.net>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        "David S . Miller" <davem@...emloft.net>, paulmck@...nel.org,
        joel@...lfernandes.org,
        "Naveen N . Rao" <naveen.n.rao@...ux.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>
Subject: [RFT PATCH 02/13] kprobes: Remove redundant arch_disarm_kprobe() call

Fix to remove redundant arch_disarm_kprobe() call in
force_unoptimize_kprobe(). This arch_disarm_kprobe()
will be done if the kprobe is optimized but disabled,
but that means the kprobe (optprobe) is unused
(unoptimizing) state.
In that case, unoptimize_kprobe() puts it in freeing_list
and kprobe_optimizer automatically disarm it. So this
arch_disarm_kprobe() is redundant.

Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 kernel/kprobes.c |    2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 52b05ab9c323..a2c755e79be7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -674,8 +674,6 @@ static void force_unoptimize_kprobe(struct optimized_kprobe *op)
 	lockdep_assert_cpus_held();
 	arch_unoptimize_kprobe(op);
 	op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
-	if (kprobe_disabled(&op->kp))
-		arch_disarm_kprobe(&op->kp);
 }
 
 /* Unoptimize a kprobe if p is optimized */