From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E062720B00; Mon, 6 Nov 2023 13:20:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0GauAsP4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DCCCC433C9; Mon, 6 Nov 2023 13:20:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1699276833; bh=NxcuRvB4COdXPlBAnt0auxln4sOUOUrBBt60OYh1JOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0GauAsP4wXH4vVXlJ0u4OibqrUBZcL4CUhHtjovruN/dQ0P6xXf5Gh10+6Z8Tz9Td SsHtl2nZuq7+NUy/XK22guh79sfWiE47f3FFEmghpjfhe43K0xFEocEf18CGrZHs1t M2u2Yx5kRlIKi3v4tASGQvlrCEiuY6LOr55LR9NE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marco Elver , Heiner Kallweit , nic_swsd@realtek.com, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, Mirsad Goran Todorovac , Sasha Levin Subject: [PATCH 5.4 08/74] r8169: fix the KCSAN reported data race in rtl_rx while reading desc->opts1 Date: Mon, 6 Nov 2023 14:03:28 +0100 Message-ID: <20231106130301.992417904@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231106130301.687882731@linuxfoundation.org> References: <20231106130301.687882731@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mirsad Goran Todorovac [ Upstream commit f97eee484e71890131f9c563c5cc6d5a69e4308d ] KCSAN reported the following data-race bug: ================================================================== 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 interrupt 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 (discriminator 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-kcsan-00143-gb5cbe7c00aa0 #41 Hardware name: ASRock X670E PG Lightning/X670E PG Lightning, BIOS 1.21 04/26/2023 ================================================================== drivers/net/ethernet/realtek/r8169_main.c: ========================================== 4429 → 4430 status = 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 until 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. status = %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 prevent that from happening: 4429 → 4430 status = le32_to_cpu(READ_ONCE(desc->opts1)); 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@alu.unizg.hr/ Signed-off-by: Mirsad Goran Todorovac Acked-by: Marco Elver Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- 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/ethernet/realtek/r8169_main.c index b973198da96c3..fca2dbdd37aff 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -6114,7 +6114,7 @@ static int rtl_rx(struct net_device *dev, struct rtl8169_private *tp, u32 budget struct RxDesc *desc = tp->RxDescArray + entry; u32 status; - status = le32_to_cpu(desc->opts1); + status = le32_to_cpu(READ_ONCE(desc->opts1)); if (status & DescOwn) break; -- 2.42.0