From: Zheng Yejian zhengyejian1@huawei.com
commit 0ce0638edf5ec83343302b884fa208179580700a upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/ftrace.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5084,8 +5084,12 @@ int ftrace_regex_release(struct inode *i
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;