CVE-2025-38586

In the Linux kernel, the following vulnerability has been resolved:

bpf, arm64: Fix fp initialization for exception boundary

In the ARM64 BPF JIT when prog->aux->exception_boundary is set for a BPF

program, find_used_callee_regs() is not called because for a program

acting as exception boundary, all callee saved registers are saved.

find_used_callee_regs() sets `ctx->fp_used = true;` when it sees FP

being used in any of the instructions.

For programs acting as exception boundary, ctx->fp_used remains false

even if frame pointer is used by the program and therefore, FP is not

set-up for such programs in the prologue. This can cause the kernel to

crash due to a pagefault.

Fix it by setting ctx->fp_used = true for exception boundary programs as

fp is always saved in such programs.