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    Subject[PATCH 5.15 105/530] ftrace: Properly unset FTRACE_HASH_FL_MOD
    Date
    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
    @@ -5654,8 +5654,12 @@ 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;


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