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authorAlexei Starovoitov <ast@fb.com>2016-11-07 15:14:20 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-11-26 09:56:53 +0100
commitc5d20ce0b459b6e2d00f58b599543eb0e8e725e4 (patch)
treeea8d4b21b6ae9f7e509d0faf884210c9ed8b0bca
parentf271087fb2ea6eb4352340893225655f6ab491d0 (diff)
ftrace: Ignore FTRACE_FL_DISABLED while walking dyn_ftrace records
commit 977c1f9c8c022d0173181766b34a0db3705265a4 upstream. 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 Fixes: b7ffffbb46f2 "ftrace: Add infrastructure for delayed enabling of module functions" Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/trace/ftrace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 84752c8e28b5..fb26c78309aa 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2757,7 +2757,7 @@ 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();