From 977c1f9c8c022d0173181766b34a0db3705265a4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 7 Nov 2016 15:14:20 -0800 Subject: [PATCH] ftrace: Ignore FTRACE_FL_DISABLED while walking dyn_ftrace records ftrace_shutdown() checks for sanity of ftrace records and if dyn_ftrace->flags is not zero, it will warn. It can happen that 'flags' are set to FTRACE_FL_DISABLED at this point, since some module was loaded, but before ftrace_module_enable() cleared the flags for this module. In other words the module.c is doing: ftrace_module_init(mod); // calls ftrace_update_code() that sets flags=FTRACE_FL_DISABLED ... // here ftrace_shutdown() is called that warns, since err = prepare_coming_module(mod); // didn't have a chance to clear FTRACE_FL_DISABLED Fix it by ignoring disabled records. It's similar to what __ftrace_hash_rec_update() is already doing. Link: http://lkml.kernel.org/r/1478560460-3818619-1-git-send-email-ast@fb.com Cc: stable@vger.kernel.org Fixes: b7ffffbb46f2 "ftrace: Add infrastructure for delayed enabling of module functions" Signed-off-by: Alexei Starovoitov Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2050a765..326498b 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2763,7 +2763,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) struct dyn_ftrace *rec; do_for_each_ftrace_rec(pg, rec) { - if (FTRACE_WARN_ON_ONCE(rec->flags)) + if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED)) pr_warn(" %pS flags:%lx\n", (void *)rec->ip, rec->flags); } while_for_each_ftrace_rec(); -- 2.7.4