From: Masami Hiramatsu <mhiramat@kernel.org>
To: Ingo Molnar <mingo@kernel.org>, Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Uladzislau Rezki <urezki@gmail.com>,
LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Andrew Morton <akpm@linux-foundation.org>,
Daniel Axtens <dja@axtens.net>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraju@codeaurora.org>,
Joel Fernandes <joel@joelfernandes.org>,
Michal Hocko <mhocko@suse.com>,
"Theodore Y . Ts'o" <tytso@mit.edu>,
Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: [PATCH] kprobes: Fix to delay the kprobes jump optimization
Date: Thu, 18 Feb 2021 23:29:23 +0900 [thread overview]
Message-ID: <161365856280.719838.12423085451287256713.stgit@devnote2> (raw)
Commit 36dadef23fcc ("kprobes: Init kprobes in early_initcall")
moved the kprobe setup in early_initcall(), which includes kprobe
jump optimization.
The kprobes jump optimizer involves synchronize_rcu_tasks() which
depends on the ksoftirqd and rcu_spawn_tasks_*(). However, since
those are setup in core_initcall(), kprobes jump optimizer can not
run at the early_initcall().
To avoid this issue, make the kprobe optimization disabled in the
early_initcall() and enables it in subsys_initcall().
Note that non-optimized kprobes is still available after
early_initcall(). Only jump optimization is delayed.
Fixes: 36dadef23fcc ("kprobes: Init kprobes in early_initcall")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
---
kernel/kprobes.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index d5a3eb74a657..779d8322e307 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -861,7 +861,6 @@ static void try_to_optimize_kprobe(struct kprobe *p)
cpus_read_unlock();
}
-#ifdef CONFIG_SYSCTL
static void optimize_all_kprobes(void)
{
struct hlist_head *head;
@@ -887,6 +886,7 @@ static void optimize_all_kprobes(void)
mutex_unlock(&kprobe_mutex);
}
+#ifdef CONFIG_SYSCTL
static void unoptimize_all_kprobes(void)
{
struct hlist_head *head;
@@ -2497,18 +2497,14 @@ static int __init init_kprobes(void)
}
}
-#if defined(CONFIG_OPTPROBES)
-#if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
- /* Init kprobe_optinsn_slots */
- kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
-#endif
- /* By default, kprobes can be optimized */
- kprobes_allow_optimization = true;
-#endif
-
/* By default, kprobes are armed */
kprobes_all_disarmed = false;
+#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
+ /* Init kprobe_optinsn_slots for allocation */
+ kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
+#endif
+
err = arch_init_kprobes();
if (!err)
err = register_die_notifier(&kprobe_exceptions_nb);
@@ -2523,6 +2519,21 @@ static int __init init_kprobes(void)
}
early_initcall(init_kprobes);
+#if defined(CONFIG_OPTPROBES)
+static int __init init_optprobes(void)
+{
+ /*
+ * Enable kprobe optimization - this kicks the optimizer which
+ * depends on synchronize_rcu_tasks() and ksoftirqd, that is
+ * not spawned in early initcall. So delay the optimization.
+ */
+ optimize_all_kprobes();
+
+ return 0;
+}
+subsys_initcall(init_optprobes);
+#endif
+
#ifdef CONFIG_DEBUG_FS
static void report_probe(struct seq_file *pi, struct kprobe *p,
const char *sym, int offset, char *modname, struct kprobe *pp)
next reply other threads:[~2021-02-18 17:21 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-18 14:29 Masami Hiramatsu [this message]
2021-02-18 15:15 ` [PATCH] kprobes: Fix to delay the kprobes jump optimization Paul E. McKenney
2021-02-19 8:17 ` Sebastian Andrzej Siewior
2021-02-19 10:49 ` Uladzislau Rezki
2021-02-19 10:57 ` Sebastian Andrzej Siewior
2021-02-19 11:13 ` Uladzislau Rezki
2021-02-19 11:17 ` Sebastian Andrzej Siewior
2021-02-19 11:23 ` Uladzislau Rezki
2021-02-19 11:27 ` Uladzislau Rezki
2021-02-19 18:18 ` Paul E. McKenney
2021-02-19 18:33 ` Paul E. McKenney
2021-02-19 19:34 ` Paul E. McKenney
2021-02-19 20:02 ` Steven Rostedt
2021-02-19 21:22 ` Paul E. McKenney
2021-02-22 10:21 ` Sebastian Andrzej Siewior
2021-02-22 12:54 ` Uladzislau Rezki
2021-02-22 15:09 ` Paul E. McKenney
2021-02-22 17:16 ` Uladzislau Rezki
2021-02-22 18:16 ` Paul E. McKenney
2021-02-22 19:07 ` Uladzislau Rezki
2021-02-22 21:32 ` Paul E. McKenney
2021-02-19 19:14 ` Steven Rostedt
2021-02-19 19:45 ` Paul E. McKenney
2021-02-19 20:04 ` Paul E. McKenney
2021-02-22 10:04 ` Sebastian Andrzej Siewior
2021-02-19 19:36 ` Steven Rostedt
2021-02-19 19:47 ` Paul E. McKenney
2021-02-19 19:58 ` Steven Rostedt
2021-02-19 20:04 ` Paul E. McKenney
2021-02-22 12:06 ` Masami Hiramatsu
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