From 112a0e4171e111e963aada3fe790c71accf4d705 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 28 Jul 2020 16:34:00 +0900 Subject: kprobes: Remove unnecessary module_mutex locking from kprobe_optimizer() Since we already lock both kprobe_mutex and text_mutex in the optimizer, text will not be changed and the module unloading will be stopped inside kprobes_module_callback(). The mutex_lock() has originally been introduced to avoid conflict with text modification, at that point we didn't hold text_mutex. But after: f1c6ece23729 ("kprobes: Fix potential deadlock in kprobe_optimizer()") We started holding the text_mutex and don't need the modules mutex anyway. So remove the module_mutex locking. [ mingo: Amended the changelog. ] Suggested-by: Ingo Molnar Signed-off-by: Masami Hiramatsu Signed-off-by: Ingo Molnar Cc: Jarkko Sakkinen Link: https://lore.kernel.org/r/20200728163400.e00b09c594763349f99ce6cb@kernel.org --- kernel/kprobes.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 146c648eb943..e87679a48ba2 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -598,8 +598,6 @@ static void kprobe_optimizer(struct work_struct *work) mutex_lock(&kprobe_mutex); cpus_read_lock(); mutex_lock(&text_mutex); - /* Lock modules while optimizing kprobes */ - mutex_lock(&module_mutex); /* * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed) @@ -624,7 +622,6 @@ static void kprobe_optimizer(struct work_struct *work) /* Step 4: Free cleaned kprobes after quiesence period */ do_free_cleaned_kprobes(); - mutex_unlock(&module_mutex); mutex_unlock(&text_mutex); cpus_read_unlock(); -- cgit v1.2.3-59-g8ed1b