From: Chengming Zhou <zhouchengm...@bytedance.com> commit 8a224ffb3f52b0027f6b7279854c71a31c48fc97 upstream.
When module loaded and enabled, we will use __ftrace_replace_code for module if any ftrace_ops referenced it found. But we will get wrong ftrace_addr for module rec in ftrace_get_addr_new, because rec->flags has not been setup correctly. It can cause the callback function of a ftrace_ops has FTRACE_OPS_FL_SAVE_REGS to be called with pt_regs set to NULL. So setup correct FTRACE_FL_REGS flags for rec when we call referenced_filters to find ftrace_ops references it. Link: https://lkml.kernel.org/r/20200728180554.65203-1-zhouchengm...@bytedance.com Cc: sta...@vger.kernel.org Fixes: 8c4f3c3fa9681 ("ftrace: Check module functions being traced on reload") Signed-off-by: Chengming Zhou <zhouchengm...@bytedance.com> Signed-off-by: Muchun Song <songmuc...@bytedance.com> Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- kernel/trace/ftrace.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5665,8 +5665,11 @@ static int referenced_filters(struct dyn int cnt = 0; for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { - if (ops_references_rec(ops, rec)) - cnt++; + if (ops_references_rec(ops, rec)) { + cnt++; + if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) + rec->flags |= FTRACE_FL_REGS; + } } return cnt; @@ -5843,8 +5846,8 @@ void ftrace_module_enable(struct module if (ftrace_start_up) cnt += referenced_filters(rec); - /* This clears FTRACE_FL_DISABLED */ - rec->flags = cnt; + rec->flags &= ~FTRACE_FL_DISABLED; + rec->flags += cnt; if (ftrace_start_up && cnt) { int failed = __ftrace_replace_code(rec, 1);
