CVE-2023-53694

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> riscv: ftrace: Fixup panic by disabling preemption<br /> <br /> In RISCV, we must use an AUIPC + JALR pair to encode an immediate,<br /> forming a jump that jumps to an address over 4K. This may cause errors<br /> if we want to enable kernel preemption and remove dependency from<br /> patching code with stop_machine(). For example, if a task was switched<br /> out on auipc. And, if we changed the ftrace function before it was<br /> switched back, then it would jump to an address that has updated 11:0<br /> bits mixing with previous XLEN:12 part.<br /> <br /> p: patched area performed by dynamic ftrace<br /> ftrace_prologue:<br /> p| REG_S ra, -SZREG(sp)<br /> p| auipc ra, 0x? ------------&gt; preempted<br /> ...<br /> change ftrace function<br /> ...<br /> p| jalr -?(ra)