Zilin Guan

The Linux kernel has resolved a NULL Pointer Dereference issue in its fgraph component. The problem occurred in the ftrace return to handler() function, where a loop iterates over fgraph array[] elements. If the compiler reloads fgraph array[] after checking for a fgraph stub, it may conflict with an update that introduces a fgraph stub, resulting in a NULL pointer dereference. To fix this, a READ ONCE() has been added when accessing fgraph array[] to ensure that the compared gops match the processed gops later. An exploit for this issue is not publicly available, but a similar patch can be found in commit 63a8dfb. The vulnerable software is the Linux kernel, but the specific versions are not mentioned. #LinuxKernel #NULLPointerDereference #fgraph #READ ONCE #functiongraph