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[ Upstream commitb114fcee76] 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. Fixes:5d4fa9ec56("bpf, arm64: Avoid blindly saving/restoring all callee-saved registers") Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Xu Kuohai <xukuohai@huawei.com> Link: https://lore.kernel.org/bpf/20250722133410.54161-2-puranjay@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>