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Commit e755b65a authored by Zheng Yejian's avatar Zheng Yejian Committed by Greg Kroah-Hartman
Browse files

ftrace: Properly unset FTRACE_HASH_FL_MOD 

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: 8c08f0d5 ("ftrace: Have cached module filters be an active filter")
Signed-off-by: default avatarZheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f66de709

kernel/trace/ftrace.c

+6 −2
Original line number Diff line number Diff line
@@ -5084,8 +5084,12 @@ int ftrace_regex_release(struct inode *inode, struct file *file) 


		if (filter_hash) {

			orig_hash = &iter->ops->func_hash->filter_hash;

			if (iter->tr && !list_empty(&iter->tr->mod_trace))

			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;