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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: "Gustavo A . R . Silva" <gustavoars@kernel.org>,
	Anders Roxell <anders.roxell@linaro.org>,
	paulmck@kernel.org, joel@joelfernandes.org,
	"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
	David Miller <davem@davemloft.net>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <peterz@infradead.org>,
	Ziqian SUN <zsun@redhat.com>
Subject: [PATCH -tip V6 4/6] kprobes: Remove redundant arch_disarm_kprobe() call
Date: Tue, 12 May 2020 17:03:07 +0900	[thread overview]
Message-ID: <158927058719.27680.17183632908465341189.stgit@devnote2> (raw)
In-Reply-To: <158927054236.27680.18209720730136003586.stgit@devnote2>

Fix to remove redundant arch_disarm_kprobe() call in
force_unoptimize_kprobe(). This arch_disarm_kprobe()
will be invoked if the kprobe is optimized but disabled,
but that means the kprobe (optprobe) is unused (and
unoptimized) state.

In that case, unoptimize_kprobe() puts it in freeing_list
and kprobe_optimizer (do_unoptimize_kprobes()) automatically
disarm it. Thus this arch_disarm_kprobe() is redundant.

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

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 6d76a6e3e1a5..627fc1b7011a 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -675,8 +675,6 @@ 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 */


  parent reply	other threads:[~2020-05-12  8:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-12  8:02 [PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups Masami Hiramatsu
2020-05-12  8:02 ` [PATCH -tip V6 1/6] kprobes: Suppress the suspicious RCU warning on kprobes Masami Hiramatsu
2020-05-12  8:02 ` [PATCH -tip V6 2/6] kprobes: Use non RCU traversal APIs on kprobe_tables if possible Masami Hiramatsu
2020-05-12  8:02 ` [PATCH -tip V6 3/6] kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex Masami Hiramatsu
2020-05-12  8:03 ` Masami Hiramatsu [this message]
2020-05-12  8:03 ` [PATCH -tip V6 5/6] kretprobe: Prevent triggering kretprobe from within kprobe_flush_task Masami Hiramatsu
2020-05-12  8:03 ` [PATCH -tip V6 6/6] kprobes: Replace zero-length array with flexible-array Masami Hiramatsu
2020-05-27 14:49 ` [PATCH -tip V6 0/6] kprobes: Fixes mutex, rcu-list warnings and cleanups Masami Hiramatsu
2020-06-14 15:37   ` Jiri Olsa
2020-06-16 19:01     ` Steven Rostedt
2020-06-16 19:44       ` Jiri Olsa
2020-06-17 14:40       ` Masami Hiramatsu

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