| Message ID | 20231018193434.344176-3-mirsad.todorovac@alu.unizg.hr (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v4,1/3] r8169: fix the KCSAN reported data-race in rtl_tx() while reading tp->cur_tx | expand |
On Wed, Oct 18, 2023 at 09:34:38PM +0200, Mirsad Goran Todorovac wrote: > 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@google.com> > Cc: Heiner Kallweit <hkallweit1@gmail.com> > Cc: nic_swsd@realtek.com > Cc: "David S. Miller" <davem@davemloft.net> > Cc: Eric Dumazet <edumazet@google.com> > Cc: Jakub Kicinski <kuba@kernel.org> > Cc: Paolo Abeni <pabeni@redhat.com> > 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 <mirsad.todorovac@alu.unizg.hr> > Acked-by: Marco Elver <elver@google.com> Reviewed-by: Simon Horman <horms@kernel.org>
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/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 rtl8169_private *tp, int budget dma_addr_t addr; u32 status; - status = le32_to_cpu(desc->opts1); + status = le32_to_cpu(READ_ONCE(desc->opts1)); if (status & DescOwn) break;
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@google.com> Cc: Heiner Kallweit <hkallweit1@gmail.com> Cc: nic_swsd@realtek.com Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> 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 <mirsad.todorovac@alu.unizg.hr> Acked-by: Marco Elver <elver@google.com> --- v4: fixed the Fixes: tag for 2/3. v3: fixed the Fixes: tag for 3/3. v2: fixed double Signed-off-by: tag drivers/net/ethernet/realtek/r8169_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)