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authorMasami Hiramatsu <mhiramat@kernel.org>2020-07-28 16:34:00 +0900
committerIngo Molnar <mingo@kernel.org>2020-07-28 13:19:05 +0200
commit112a0e4171e111e963aada3fe790c71accf4d705 (patch)
treed74254e8ac496dc145e75e3c355a4f8df2986ae9 /kernel/kprobes.c
parente89d4ca1df630378bde3e36c42001b755b0044fe (diff)
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 <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Link: https://lore.kernel.org/r/20200728163400.e00b09c594763349f99ce6cb@kernel.org
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c3
1 files changed, 0 insertions, 3 deletions
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();