From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7684CC77B7F for ; Mon, 8 May 2023 10:04:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233991AbjEHKEB (ORCPT ); Mon, 8 May 2023 06:04:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233985AbjEHKEA (ORCPT ); Mon, 8 May 2023 06:04:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA6BD2EB3B for ; Mon, 8 May 2023 03:03:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 587BA622E1 for ; Mon, 8 May 2023 10:03:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D8CFC433D2; Mon, 8 May 2023 10:03:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1683540237; bh=QNvySg/455ZPe+JjSomXiDEzlDkxlTK3w57SdW4oILs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QtX78b8DwNJDA5g5clD9eu6DLANWiYZkpHwR0BYZRwWcC9r38AQ+mE0hai/9dbVXu Jtl3M/nEXd5FdDuKppWzzYvvKbAvNncvPueQsraX9IJEBTCfaT4B975Dr1fBlYBfI2 VbQJJNzEqLPX9isM+ryhJVQJe9ClBnOxNlXIL8C8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.1 289/611] libbpf: Fix ld_imm64 copy logic for ksym in light skeleton. Date: Mon, 8 May 2023 11:42:11 +0200 Message-Id: <20230508094431.787505518@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230508094421.513073170@linuxfoundation.org> References: <20230508094421.513073170@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Alexei Starovoitov [ Upstream commit a506d6ce1dd184051037dc9d26c3eb187c9fe625 ] Unlike normal libbpf the light skeleton 'loader' program is doing btf_find_by_name_kind() call at run-time to find ksym in the kernel and populate its {btf_id, btf_obj_fd} pair in ld_imm64 insn. To avoid doing the search multiple times for the same ksym it remembers the first patched ld_imm64 insn and copies {btf_id, btf_obj_fd} from it into subsequent ld_imm64 insn. Fix a bug in copying logic, since it may incorrectly clear BPF_PSEUDO_BTF_ID flag. Also replace always true if (btf_obj_fd >= 0) check with unconditional JMP_JA to clarify the code. Fixes: d995816b77eb ("libbpf: Avoid reload of imm for weak, unresolved, repeating ksym") Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20230319203014.55866-1-alexei.starovoitov@gmail.com Signed-off-by: Sasha Levin --- tools/lib/bpf/gen_loader.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/tools/lib/bpf/gen_loader.c b/tools/lib/bpf/gen_loader.c index 23f5c46708f8f..b74c82bb831e6 100644 --- a/tools/lib/bpf/gen_loader.c +++ b/tools/lib/bpf/gen_loader.c @@ -804,11 +804,13 @@ static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, return; /* try to copy from existing ldimm64 insn */ if (kdesc->ref > 1) { - move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4, - kdesc->insn + offsetof(struct bpf_insn, imm)); move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4, kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)); - /* jump over src_reg adjustment if imm is not 0, reuse BPF_REG_0 from move_blob2blob */ + move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4, + kdesc->insn + offsetof(struct bpf_insn, imm)); + /* jump over src_reg adjustment if imm (btf_id) is not 0, reuse BPF_REG_0 from move_blob2blob + * If btf_id is zero, clear BPF_PSEUDO_BTF_ID flag in src_reg of ld_imm64 insn + */ emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3)); goto clear_src_reg; } @@ -831,7 +833,7 @@ static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm))); /* skip src_reg adjustment */ - emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3)); + emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 3)); clear_src_reg: /* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */ reg_mask = src_reg_mask(); -- 2.39.2