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authorMasami Hiramatsu <mhiramat@kernel.org>2021-02-18 23:29:23 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-02-19 14:57:12 -0500
commitc85c9a2c6e368dc94907e63babb18a9788e5c9b6 (patch)
tree231d254e73c29794c640a607d6c2c5c20e5456df /kernel/kprobes.c
parente23db805da2dfc39e5281b5efd3e36d132aa83af (diff)
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kprobes: Fix to delay the kprobes jump optimization
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. Link: https://lkml.kernel.org/r/161365856280.719838.12423085451287256713.stgit@devnote2 Fixes: 36dadef23fcc ("kprobes: Init kprobes in early_initcall") Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: RCU <rcu@vger.kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Daniel Axtens <dja@axtens.net> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Neeraj Upadhyay <neeraju@codeaurora.org> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Michal Hocko <mhocko@suse.com> Cc: "Theodore Y . Ts'o" <tytso@mit.edu> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: stable@vger.kernel.org Reported-by: Paul E. McKenney <paulmck@kernel.org> Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reported-by: Uladzislau Rezki <urezki@gmail.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c31
1 files changed, 21 insertions, 10 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index dd1d027455c4..745f08fdd7a6 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -861,7 +861,6 @@ out:
cpus_read_unlock();
}
-#ifdef CONFIG_SYSCTL
static void optimize_all_kprobes(void)
{
struct hlist_head *head;
@@ -887,6 +886,7 @@ out:
mutex_unlock(&kprobe_mutex);
}
+#ifdef CONFIG_SYSCTL
static void unoptimize_all_kprobes(void)
{
struct hlist_head *head;
@@ -2500,18 +2500,14 @@ 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);
@@ -2526,6 +2522,21 @@ 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)