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[2620:137:e000::1:20]) by mx.google.com with ESMTP id d11-20020a056402144b00b0046fe2f565cdsi1360891edx.363.2022.12.15.21.59.21; Thu, 15 Dec 2022 21:59:58 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=QzFwd1Mm; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229737AbiLPFyr (ORCPT + 99 others); Fri, 16 Dec 2022 00:54:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229480AbiLPFyp (ORCPT ); Fri, 16 Dec 2022 00:54:45 -0500 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43DBE36D64; Thu, 15 Dec 2022 21:54:43 -0800 (PST) Received: by mail-pg1-x52c.google.com with SMTP id s196so1105497pgs.3; Thu, 15 Dec 2022 21:54:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=9nHmBQYF3nBNqyNj2PFzrUNwBMnuzgTKWyjZljTDo88=; b=QzFwd1MmmPpBd2ezWngjf7PUFaMaB52m8IiN67Yqc8i91g+Tdth/SezAJD12ThbR/2 9Ub0A414NsZr4WUwBcNy9zE/3cxR2w3aGJgdpIpW5WbBa/qLCV8JUsrEVzqQ0Uw0GVrx JKBmdQGNgn1SZhPLZt3chZrVrc0VQAJCwHpP9zoIYeJ8evCSbQEE80OMuAz0WUYALvJL yao3BPSdY77o4M6fbi34ZJsJTb2MaBAVi/O8xIj+79XOZ3dpNIG6S8xR4p3uH2b/qU5K VbbYUtBI/A1Ofpa586Yi57dNxnPtuc/vnAnlC5eFRwc+X3eng66MA+z5zgxVCezaQPPG qTig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=9nHmBQYF3nBNqyNj2PFzrUNwBMnuzgTKWyjZljTDo88=; b=gfaGuEh9n04XpvV6THBxVGxave1GiHl7D8NJaeikBx+14XJaI2d/bKdIJ8IxdDZtb3 poEs3Y9k8qqmbwKS1Z325wCs1PfWn8XHxdJIpuUVPRCawuP15CcCrhmw8dgrWCdYDdUt v5buzuZ9HhVmzLgSAUJrRX2q6998WqofRSIpy6mQAQLljnSnkx5uUzpmLlSctOwTDqb0 fooaK3ouHq7gL/7uA04ebDGPlNIKmR1QD6oXzOJ61GVr21uEsmuB19hZR34vqw6yUXbY BqiXwj9/4qOaXMo21DEnm82CCFheid0S983/kbaahMyTNhVjBjQgls21OJ8pAK+8bdxA GW9g== X-Gm-Message-State: ANoB5pmulxP6WTlk7eyoOXqMNjM6HODjJkbttMLcKgN6IT9SILMudbR2 br7ChmTBga18A+XDGgfq3FcQ26CmhA== X-Received: by 2002:a62:870d:0:b0:576:f02e:d0ef with SMTP id i13-20020a62870d000000b00576f02ed0efmr31320268pfe.4.1671170082306; Thu, 15 Dec 2022 21:54:42 -0800 (PST) Received: from localhost.localdomain ([144.214.0.6]) by smtp.gmail.com with ESMTPSA id g15-20020aa79f0f000000b0056b2e70c2f5sm593246pfr.25.2022.12.15.21.54.39 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 15 Dec 2022 21:54:41 -0800 (PST) From: Hao Sun To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, davem@davemloft.net, linux-kernel@vger.kernel.org, Hao Sun Subject: [PATCH bpf-next] bpf: dup xlated insns with kvmalloc+memcpy Date: Fri, 16 Dec 2022 13:54:35 +0800 Message-Id: <20221216055436.4698-1-sunhao.th@gmail.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1752349171766751341?= X-GMAIL-MSGID: =?utf-8?q?1752349171766751341?= Currently, kmemdup() is used for allocating and copying xlated insns in bpf_insn_prepare_dump(). The following warning can be triggered when dup large amount of insns (roughly BPF_COMPLEXITY_LIMIT_INSNS/2) because kmemdup() uses kmalloc() which would fail when allocing size is too big, leading to failure in dump xlated insns: WARNING: CPU: 2 PID: 7060 at mm/page_alloc.c:5534 Call Trace: __alloc_pages_node include/linux/gfp.h:237 [inline] alloc_pages_node include/linux/gfp.h:260 [inline] __kmalloc_large_node+0x81/0x160 mm/slab_common.c:1096 __do_kmalloc_node mm/slab_common.c:943 [inline] __kmalloc_node_track_caller.cold+0x5/0x5d mm/slab_common.c:975 kmemdup+0x29/0x60 mm/util.c:129 kmemdup include/linux/fortify-string.h:585 [inline] bpf_insn_prepare_dump kernel/bpf/syscall.c:3820 [inline] bpf_prog_get_info_by_fd+0x9a3/0x2cb0 kernel/bpf/syscall.c:3975 bpf_obj_get_info_by_fd kernel/bpf/syscall.c:4297 [inline] __sys_bpf+0x3928/0x56f0 kernel/bpf/syscall.c:5004 __do_sys_bpf kernel/bpf/syscall.c:5069 [inline] __se_sys_bpf kernel/bpf/syscall.c:5067 [inline] ... So use kvmalloc()+memcpy() to fix this, for small size of insns, this is same as kmemdup(), but this also support dup large amount of xlated insns. Signed-off-by: Hao Sun --- kernel/bpf/syscall.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) base-commit: 0e43662e61f2569500ab83b8188c065603530785 diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 35972afb6850..06229fddac0d 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3831,10 +3831,10 @@ static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog, u8 code; int i; - insns = kmemdup(prog->insnsi, bpf_prog_insn_size(prog), - GFP_USER); - if (!insns) + insns = kvmalloc(bpf_prog_insn_size(prog), GFP_USER | __GFP_NOWARN); + if (unlikely(!insns)) return insns; + memcpy(insns, prog->insnsi, bpf_prog_insn_size(prog)); for (i = 0; i < prog->len; i++) { code = insns[i].code; @@ -3992,7 +3992,7 @@ static int bpf_prog_get_info_by_fd(struct file *file, uinsns = u64_to_user_ptr(info.xlated_prog_insns); ulen = min_t(u32, info.xlated_prog_len, ulen); fault = copy_to_user(uinsns, insns_sanitized, ulen); - kfree(insns_sanitized); + kvfree(insns_sanitized); if (fault) return -EFAULT; }