This is a note to let you know that I've just added the patch titled
ftrace: Fix issue that 'direct->addr' not restored in modify_ftrace_direct()
to the 6.2-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-fix-issue-that-direct-addr-not-restored-in-modify_ftrace_direct.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2a2d8c51defb446e8d89a83f42f8e5cd529111e9 Mon Sep 17 00:00:00 2001
From: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
Date: Thu, 30 Mar 2023 10:52:23 +0800
Subject: ftrace: Fix issue that 'direct->addr' not restored in modify_ftrace_direct()
From: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
commit 2a2d8c51defb446e8d89a83f42f8e5cd529111e9 upstream.
Syzkaller report a WARNING: "WARN_ON(!direct)" in modify_ftrace_direct().
Root cause is 'direct->addr' was changed from 'old_addr' to 'new_addr' but
not restored if error happened on calling ftrace_modify_direct_caller().
Then it can no longer find 'direct' by that 'old_addr'.
To fix it, restore 'direct->addr' to 'old_addr' explicitly in error path.
Link: https://lore.kernel.org/linux-trace-kernel/20230330025223.1046087-1-zhengyejian1@xxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Cc: <mhiramat@xxxxxxxxxx>
Cc: <mark.rutland@xxxxxxx>
Cc: <ast@xxxxxxxxxx>
Cc: <daniel@xxxxxxxxxxxxx>
Fixes: 8a141dd7f706 ("ftrace: Fix modify_ftrace_direct.")
Signed-off-by: Zheng Yejian <zhengyejian1@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/ftrace.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5568,12 +5568,15 @@ int modify_ftrace_direct(unsigned long i
ret = 0;
}
- if (unlikely(ret && new_direct)) {
- direct->count++;
- list_del_rcu(&new_direct->next);
- synchronize_rcu_tasks();
- kfree(new_direct);
- ftrace_direct_func_count--;
+ if (ret) {
+ direct->addr = old_addr;
+ if (unlikely(new_direct)) {
+ direct->count++;
+ list_del_rcu(&new_direct->next);
+ synchronize_rcu_tasks();
+ kfree(new_direct);
+ ftrace_direct_func_count--;
+ }
}
out_unlock:
Patches currently in stable-queue which might be from zhengyejian1@xxxxxxxxxx are
queue-6.2/ftrace-fix-issue-that-direct-addr-not-restored-in-modify_ftrace_direct.patch
