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Message-ID: <20231106130301.992417904@linuxfoundation.org>
Date: Mon, 6 Nov 2023 14:03:28 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: stable@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
patches@...ts.linux.dev,
Marco Elver <elver@...gle.com>,
Heiner Kallweit <hkallweit1@...il.com>,
nic_swsd@...ltek.com,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
netdev@...r.kernel.org,
Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 08/74] r8169: fix the KCSAN reported data race in rtl_rx while reading desc->opts1
5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
[ 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 <elver@...gle.com>
Cc: Heiner Kallweit <hkallweit1@...il.com>
Cc: nic_swsd@...ltek.com
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Eric Dumazet <edumazet@...gle.com>
Cc: Jakub Kicinski <kuba@...nel.org>
Cc: Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org
Link: https://lore.kernel.org/lkml/dc7fc8fa-4ea4-e9a9-30a6-7c83e6b53188@alu.unizg.hr/
Signed-off-by: Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
Acked-by: Marco Elver <elver@...gle.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
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
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