[PATCH 5.10 039/124] ftrace: Fix issue that direct->addr not restored in modify_ftrace_direct()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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
@@ -5390,12 +5390,15 @@ 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:





[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux