This is a note to let you know that I've just added the patch titled
ftrace: Ignore FTRACE_FL_DISABLED while walking dyn_ftrace records
to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ftrace-ignore-ftrace_fl_disabled-while-walking-dyn_ftrace-records.patch
and it can be found in the queue-4.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 977c1f9c8c022d0173181766b34a0db3705265a4 Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@xxxxxx>
Date: Mon, 7 Nov 2016 15:14:20 -0800
Subject: ftrace: Ignore FTRACE_FL_DISABLED while walking dyn_ftrace records
From: Alexei Starovoitov <ast@xxxxxx>
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@xxxxxx
Fixes: b7ffffbb46f2 "ftrace: Add infrastructure for delayed enabling of module functions"
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/ftrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2757,7 +2757,7 @@ static int ftrace_shutdown(struct ftrace
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();
Patches currently in stable-queue which might be from ast@xxxxxx are
queue-4.8/ftrace-ignore-ftrace_fl_disabled-while-walking-dyn_ftrace-records.patch
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