[PATCH 1/2] ftrace: clear module from hash of all ftrace ops

From: Chengming Zhou
Date: Tue Jul 28 2020 - 06:27:31 EST


We should clear module from hash of all ops on ftrace_ops_list when
module going, or the ops including these modules will be matched
wrongly by new module loaded later.

Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
kernel/trace/ftrace.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1903b80db6eb..fca01a168ae5 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6223,18 +6223,20 @@ clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
/* Clear any records from hashs */
static void clear_mod_from_hashes(struct ftrace_page *pg)
{
- struct trace_array *tr;
+ struct ftrace_ops *op;

- mutex_lock(&trace_types_lock);
- list_for_each_entry(tr, &ftrace_trace_arrays, list) {
- if (!tr->ops || !tr->ops->func_hash)
+ mutex_lock(&ftrace_lock);
+
+ do_for_each_ftrace_op(op, ftrace_ops_list) {
+ if (!op->func_hash)
continue;
- mutex_lock(&tr->ops->func_hash->regex_lock);
- clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
- clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
- mutex_unlock(&tr->ops->func_hash->regex_lock);
- }
- mutex_unlock(&trace_types_lock);
+ mutex_lock(&op->func_hash->regex_lock);
+ clear_mod_from_hash(pg, op->func_hash->filter_hash);
+ clear_mod_from_hash(pg, op->func_hash->notrace_hash);
+ mutex_unlock(&op->func_hash->regex_lock);
+ } while_for_each_ftrace_op(op);
+
+ mutex_unlock(&ftrace_lock);
}

static void ftrace_free_mod_map(struct rcu_head *rcu)
--
2.20.1