When executing following commands like what document said, but the log
"#### all functions enabled ####" was not shown as expect:
1. Set a 'mod' filter:
$ echo 'write*:mod:ext3' > /sys/kernel/tracing/set_ftrace_filter
2. Invert above filter:
$ echo '!write*:mod:ext3' >> /sys/kernel/tracing/set_ftrace_filter
3. Read the file:
$ cat /sys/kernel/tracing/set_ftrace_filter
By some debugging, I found that flag FTRACE_HASH_FL_MOD was not unset
after inversion like above step 2 and then result of ftrace_hash_empty()
is incorrect.
Link: https://lkml.kernel.org/r/20220926152008.2239274-1-zhengyejian1@huawei.com
Cc: <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes:
8c08f0d5c6fb ("ftrace: Have cached module filters be an active filter")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
if (filter_hash) {
orig_hash = &iter->ops->func_hash->filter_hash;
- if (iter->tr && !list_empty(&iter->tr->mod_trace))
- iter->hash->flags |= FTRACE_HASH_FL_MOD;
+ if (iter->tr) {
+ if (list_empty(&iter->tr->mod_trace))
+ iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
+ else
+ iter->hash->flags |= FTRACE_HASH_FL_MOD;
+ }
} else
orig_hash = &iter->ops->func_hash->notrace_hash;