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[2620:137:e000::3:7]) by mx.google.com with ESMTPS id p28-20020a637f5c000000b005b503f56f03si3268641pgn.827.2023.10.16.00.36.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Oct 2023 00:36:50 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=A5jCAIPT; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by snail.vger.email (Postfix) with ESMTP id 471ED80AEFD1; Mon, 16 Oct 2023 00:36:49 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at snail.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232370AbjJPHgp (ORCPT + 99 others); Mon, 16 Oct 2023 03:36:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232268AbjJPHgh (ORCPT ); Mon, 16 Oct 2023 03:36:37 -0400 Received: from mail-vs1-xe34.google.com (mail-vs1-xe34.google.com [IPv6:2607:f8b0:4864:20::e34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C413EDC for ; Mon, 16 Oct 2023 00:36:34 -0700 (PDT) Received: by mail-vs1-xe34.google.com with SMTP id ada2fe7eead31-457ee0df54eso263392137.0 for ; Mon, 16 Oct 2023 00:36:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1697441794; x=1698046594; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=THb+AjJq57EQO0I6/2CvYDrwJ5gGh/j3ZWSQgme6FCo=; b=A5jCAIPTZWmSrlGYPNj7AaNYqB8FFBTrlyxMtZjXH3dAqb4kN5YuYdIzYfhURqvtOZ VbZ+jibaTXrU216FECS1W8bTfmTmQtQYxvhsqMfCQZ5xxuE5EkLdgkIHlu0MxopUnPvg vqxywVCyuhemQZYjPVatMf08QeTJsDIVD+IJCdUbfuHljQoZzqfC0suTv5O7y56CvQ0V 5x20+QB5jnBX3uZfzSYGiTds/8wijyk2uBSB8jlhW34foBO50ovRaNnn7112AfJk0DnD Nq2krDbs7azuDl48jyvow5uC8GIySU9G2c/79XVTr4SOxdDHaA1i139vnu/RpXkBMs2S RbOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697441794; x=1698046594; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=THb+AjJq57EQO0I6/2CvYDrwJ5gGh/j3ZWSQgme6FCo=; b=KLtTPHo4yKs3SMFu5EFQxLvnxagVkNpdETsTMcOufv3m+J9INAEau7ewTu/Y4CyTSR vSR98+FmxP+88KeDzwytHx1J+OqF45ODygOwpHYipl+l6JCC+6CQfmY5v71F9RH83CYb CRMeQiPbDY/kuvD06wuXguc/kRu+WFsekL4Ptei8MzdFaYRor+AemHcTGj93mzR78bAD 3C1aeyLHHjjAeVEPCnP3I45FPjD3EBdrJbR9BksBRk7q4gIa2W0ghvUeVkd6Sk3ChjRl lLgjb23nEumGLYwHddssfmLSdeTNxlDP57WLeRAhsiMf/hFuypPniGdqO7Q3h+P+LmXX NuXg== X-Gm-Message-State: AOJu0YwzdsxDwuyucbkZfI693Wh0LeNJNBgGt14UX9eSJv4t13bS6x4z YNgg512e31PNRwzXI6zrVQsJWREV0XvhJmpRnybOTA== X-Received: by 2002:a05:6102:23f5:b0:457:c725:4bdb with SMTP id p21-20020a05610223f500b00457c7254bdbmr7218817vsc.28.1697441793768; Mon, 16 Oct 2023 00:36:33 -0700 (PDT) MIME-Version: 1.0 References: <20231014031257.178630-1-mirsad.todorovac@alu.unizg.hr> <20231014031257.178630-3-mirsad.todorovac@alu.unizg.hr> In-Reply-To: <20231014031257.178630-3-mirsad.todorovac@alu.unizg.hr> From: Marco Elver Date: Mon, 16 Oct 2023 09:35:57 +0200 Message-ID: Subject: Re: [PATCH v1 3/3] r8169: fix the KCSAN reported data race in rtl_rx while reading desc->opts1 To: Mirsad Goran Todorovac Cc: Heiner Kallweit , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, nic_swsd@realtek.com, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-17.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, ENV_AND_HDR_SPF_MATCH,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL,USER_IN_DEF_SPF_WL autolearn=unavailable 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-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Mon, 16 Oct 2023 00:36:49 -0700 (PDT) On Sat, 14 Oct 2023 at 05:16, Mirsad Goran Todorovac wrote: > > KCSAN reported the following data-race bug: > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > BUG: KCSAN: data-race in rtl8169_poll (drivers/net/ethernet/realtek/r8169= _main.c:4430 drivers/net/ethernet/realtek/r8169_main.c:4583) r8169 > > race at unknown origin, with read to 0xffff888117e43510 of 4 bytes by int= errupt on cpu 21: > rtl8169_poll (drivers/net/ethernet/realtek/r8169_main.c:4430 drivers/net/= ethernet/realtek/r8169_main.c:4583) r8169 > __napi_poll (net/core/dev.c:6527) > net_rx_action (net/core/dev.c:6596 net/core/dev.c:6727) > __do_softirq (kernel/softirq.c:553) > __irq_exit_rcu (kernel/softirq.c:427 kernel/softirq.c:632) > irq_exit_rcu (kernel/softirq.c:647) > sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1074 (discrimina= tor 14)) > asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:645) > cpuidle_enter_state (drivers/cpuidle/cpuidle.c:291) > cpuidle_enter (drivers/cpuidle/cpuidle.c:390) > call_cpuidle (kernel/sched/idle.c:135) > do_idle (kernel/sched/idle.c:219 kernel/sched/idle.c:282) > cpu_startup_entry (kernel/sched/idle.c:378 (discriminator 1)) > start_secondary (arch/x86/kernel/smpboot.c:210 arch/x86/kernel/smpboot.c:= 294) > secondary_startup_64_no_verify (arch/x86/kernel/head_64.S:433) > > value changed: 0x80003fff -> 0x3402805f > > Reported by Kernel Concurrency Sanitizer on: > CPU: 21 PID: 0 Comm: swapper/21 Tainted: G L 6.6.0-rc2-kc= san-00143-gb5cbe7c00aa0 #41 > Hardware name: ASRock X670E PG Lightning/X670E PG Lightning, BIOS 1.21 04= /26/2023 > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > drivers/net/ethernet/realtek/r8169_main.c: > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > 4429 > =E2=86=92 4430 status =3D le32_to_cpu(desc->opts1); > 4431 if (status & DescOwn) > 4432 break; > 4433 > 4434 /* This barrier is needed to keep us from reading > 4435 * any other fields out of the Rx descriptor unti= l > 4436 * we know the status of DescOwn > 4437 */ > 4438 dma_rmb(); > 4439 > 4440 if (unlikely(status & RxRES)) { > 4441 if (net_ratelimit()) > 4442 netdev_warn(dev, "Rx ERROR. statu= s =3D %08x\n", > > Marco Elver explained that dma_rmb() doesn't prevent the compiler to tear= up the access to > desc->opts1 which can be written to concurrently. READ_ONCE() should prev= ent that from > happening: > > 4429 > =E2=86=92 4430 status =3D le32_to_cpu(READ_ONCE(desc->op= ts1)); > 4431 if (status & DescOwn) > 4432 break; > 4433 > > As the consequence of this fix, this KCSAN warning was eliminated. > > Fixes: 6202806e7c03a ("r8169: drop member opts1_mask from struct rtl8169_= private") > Suggested-by: Marco Elver > Cc: Heiner Kallweit > Cc: nic_swsd@realtek.com > Cc: "David S. Miller" > Cc: Eric Dumazet > Cc: Jakub Kicinski > Cc: Paolo Abeni > Cc: netdev@vger.kernel.org > Link: https://lore.kernel.org/lkml/dc7fc8fa-4ea4-e9a9-30a6-7c83e6b53188@a= lu.unizg.hr/ > Signed-off-by: Mirsad Goran Todorovac > > Signed-off-by: Mirsad Goran Todorovac Double sign-off? Otherwise, Acked-by: Marco Elver > --- > drivers/net/ethernet/realtek/r8169_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethe= rnet/realtek/r8169_main.c > index 281aaa851847..81be6085a480 100644 > --- a/drivers/net/ethernet/realtek/r8169_main.c > +++ b/drivers/net/ethernet/realtek/r8169_main.c > @@ -4427,7 +4427,7 @@ static int rtl_rx(struct net_device *dev, struct rt= l8169_private *tp, int budget > dma_addr_t addr; > u32 status; > > - status =3D le32_to_cpu(desc->opts1); > + status =3D le32_to_cpu(READ_ONCE(desc->opts1)); > if (status & DescOwn) > break; > > -- > 2.34.1 >