* [PATCH] net: allwinner: emac: Fix double spinlock in emac_timeout
@ 2022-08-30 3:32 qianfanguijin
2022-09-06 20:54 ` Jernej Škrabec
0 siblings, 1 reply; 2+ messages in thread
From: qianfanguijin @ 2022-08-30 3:32 UTC (permalink / raw)
To: linux-kernel, linux-sunxi
Cc: Maxime Ripard, Chen-Yu Tsai, Evgeny Boger, Andre Przywara, qianfan Zhao
From: qianfan Zhao <qianfanguijin@163.com>
The system will dead due to double lock if sometings trigger
emac_timeout, next is the kernel logs:
WARNING: CPU: 2 PID: 0 at net/sched/sch_generic.c:478
dev_watchdog+0x2e4/0x2e8
NETDEV WATCHDOG: FE0 (sun4i-emac): transmit queue 0 timed out
Modules linked in:
CPU: 2 PID: 0 Comm: swapper/2 Tainted: G W 5.15.0-00047-g0848e4aeb313
Hardware name: Wisdom T3 based CCT Family
[<c010f740>] (unwind_backtrace) from [<c010b744>] (show_stack+0x10/0x14)
[<c010b744>] (show_stack) from [<c0a4d978>] (dump_stack_lvl+0x40/0x4c)
[<c0a4d978>] (dump_stack_lvl) from [<c0120734>] (__warn+0x104/0x108)
[<c0120734>] (__warn) from [<c01207b0>] (warn_slowpath_fmt+0x78/0xbc)
[<c01207b0>] (warn_slowpath_fmt) from [<c0898a54>]
(dev_watchdog+0x2e4/0x2e8)
[<c0898a54>] (dev_watchdog) from [<c019a888>] (call_timer_fn+0x3c/0x178)
[<c019a888>] (call_timer_fn) from [<c019bddc>]
(run_timer_softirq+0x540/0x624)
[<c019bddc>] (run_timer_softirq) from [<c0101298>]
(__do_softirq+0x130/0x3bc)
[<c0101298>] (__do_softirq) from [<c0127ea0>] (irq_exit+0xbc/0x100)
[<c0127ea0>] (irq_exit) from [<c017e514>] (handle_domain_irq+0x60/0x78)
[<c017e514>] (handle_domain_irq) from [<c05a6130>]
(gic_handle_irq+0x7c/0x90)
[<c05a6130>] (gic_handle_irq) from [<c0100afc>] (__irq_svc+0x5c/0x78)
Exception stack(0xc14f3f70 to 0xc14f3fb8)
3f60: 0003475c 00000000 00000001
c01188a0
3f80: c107b200 c0f06b4c c0f06b90 00000004 c1079ff8 c0c62774 00000000
00000000
3fa0: c10b2198 c14f3fc0 c0107fcc c0107fd0 60030013 ffffffff
[<c0100afc>] (__irq_svc) from [<c0107fd0>] (arch_cpu_idle+0x38/0x3c)
[<c0107fd0>] (arch_cpu_idle) from [<c0a57f38>]
(default_idle_call+0x3c/0xcc)
[<c0a57f38>] (default_idle_call) from [<c0157258>] (do_idle+0xdc/0x13c)
[<c0157258>] (do_idle) from [<c01575a4>] (cpu_startup_entry+0x18/0x1c)
[<c01575a4>] (cpu_startup_entry) from [<401015d0>] (0x401015d0)
---[ end trace a70942a1265338f1 ]---
rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
rcu: \x092-...0: (1 GPs behind) idle=75d/0/0x1 softirq=8288/8289 fqs=931
\x09(detected by 0, t=2102 jiffies, g=13485, q=1635)
Sending NMI from CPU 0 to CPUs 2:
spi_master spi2: spi2.1: timeout transferring 4 bytes@100000Hz for
110(100)ms
spidev spi2.1: SPI transfer failed: -110
Fix it.
Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
---
drivers/net/ethernet/allwinner/sun4i-emac.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c b/drivers/net/ethernet/allwinner/sun4i-emac.c
index 49759deeed8e..d49c2c18f39d 100644
--- a/drivers/net/ethernet/allwinner/sun4i-emac.c
+++ b/drivers/net/ethernet/allwinner/sun4i-emac.c
@@ -378,14 +378,11 @@ static int emac_set_mac_address(struct net_device *dev, void *p)
}
/* Initialize emac board */
-static void emac_init_device(struct net_device *dev)
+static void emac_init_device_without_lock(struct net_device *dev)
{
struct emac_board_info *db = netdev_priv(dev);
- unsigned long flags;
unsigned int reg_val;
- spin_lock_irqsave(&db->lock, flags);
-
emac_update_speed(dev);
emac_update_duplex(dev);
@@ -398,7 +395,15 @@ static void emac_init_device(struct net_device *dev)
reg_val = readl(db->membase + EMAC_INT_CTL_REG);
reg_val |= (0xf << 0) | (0x01 << 8);
writel(reg_val, db->membase + EMAC_INT_CTL_REG);
+}
+
+static void emac_init_device(struct net_device *dev)
+{
+ struct emac_board_info *db = netdev_priv(dev);
+ unsigned long flags;
+ spin_lock_irqsave(&db->lock, flags);
+ emac_init_device_without_lock(dev);
spin_unlock_irqrestore(&db->lock, flags);
}
@@ -416,7 +421,7 @@ static void emac_timeout(struct net_device *dev, unsigned int txqueue)
netif_stop_queue(dev);
emac_reset(db);
- emac_init_device(dev);
+ emac_init_device_without_lock(dev);
/* We can accept TX packets again */
netif_trans_update(dev);
netif_wake_queue(dev);
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net: allwinner: emac: Fix double spinlock in emac_timeout
2022-08-30 3:32 [PATCH] net: allwinner: emac: Fix double spinlock in emac_timeout qianfanguijin
@ 2022-09-06 20:54 ` Jernej Škrabec
0 siblings, 0 replies; 2+ messages in thread
From: Jernej Škrabec @ 2022-09-06 20:54 UTC (permalink / raw)
To: linux-kernel, linux-sunxi, qianfanguijin
Cc: Maxime Ripard, Chen-Yu Tsai, Evgeny Boger, Andre Przywara, qianfan Zhao
Dne torek, 30. avgust 2022 ob 05:32:58 CEST je qianfanguijin@163.com
napisal(a):
> From: qianfan Zhao <qianfanguijin@163.com>
>
> The system will dead due to double lock if sometings trigger
> emac_timeout, next is the kernel logs:
Maybe something like this:
"emac_timeout() callback acquires lock and so does emac_init_device(), which
called inside lock protected region. This hangs the system and produces
following warning:"
>
> WARNING: CPU: 2 PID: 0 at net/sched/sch_generic.c:478
> dev_watchdog+0x2e4/0x2e8
> NETDEV WATCHDOG: FE0 (sun4i-emac): transmit queue 0 timed out
> Modules linked in:
> CPU: 2 PID: 0 Comm: swapper/2 Tainted: G W 5.15.0-00047-g0848e4aeb313
> Hardware name: Wisdom T3 based CCT Family
> [<c010f740>] (unwind_backtrace) from [<c010b744>] (show_stack+0x10/0x14)
> [<c010b744>] (show_stack) from [<c0a4d978>] (dump_stack_lvl+0x40/0x4c)
> [<c0a4d978>] (dump_stack_lvl) from [<c0120734>] (__warn+0x104/0x108)
> [<c0120734>] (__warn) from [<c01207b0>] (warn_slowpath_fmt+0x78/0xbc)
> [<c01207b0>] (warn_slowpath_fmt) from [<c0898a54>]
> (dev_watchdog+0x2e4/0x2e8)
> [<c0898a54>] (dev_watchdog) from [<c019a888>] (call_timer_fn+0x3c/0x178)
> [<c019a888>] (call_timer_fn) from [<c019bddc>]
> (run_timer_softirq+0x540/0x624)
> [<c019bddc>] (run_timer_softirq) from [<c0101298>]
> (__do_softirq+0x130/0x3bc)
> [<c0101298>] (__do_softirq) from [<c0127ea0>] (irq_exit+0xbc/0x100)
> [<c0127ea0>] (irq_exit) from [<c017e514>] (handle_domain_irq+0x60/0x78)
> [<c017e514>] (handle_domain_irq) from [<c05a6130>]
> (gic_handle_irq+0x7c/0x90)
> [<c05a6130>] (gic_handle_irq) from [<c0100afc>] (__irq_svc+0x5c/0x78)
> Exception stack(0xc14f3f70 to 0xc14f3fb8)
> 3f60: 0003475c 00000000 00000001
> c01188a0
> 3f80: c107b200 c0f06b4c c0f06b90 00000004 c1079ff8 c0c62774 00000000
> 00000000
> 3fa0: c10b2198 c14f3fc0 c0107fcc c0107fd0 60030013 ffffffff
> [<c0100afc>] (__irq_svc) from [<c0107fd0>] (arch_cpu_idle+0x38/0x3c)
> [<c0107fd0>] (arch_cpu_idle) from [<c0a57f38>]
> (default_idle_call+0x3c/0xcc)
> [<c0a57f38>] (default_idle_call) from [<c0157258>] (do_idle+0xdc/0x13c)
> [<c0157258>] (do_idle) from [<c01575a4>] (cpu_startup_entry+0x18/0x1c)
> [<c01575a4>] (cpu_startup_entry) from [<401015d0>] (0x401015d0)
> ---[ end trace a70942a1265338f1 ]---
> rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
> rcu: \x092-...0: (1 GPs behind) idle=75d/0/0x1 softirq=8288/8289 fqs=931
> \x09(detected by 0, t=2102 jiffies, g=13485, q=1635)
> Sending NMI from CPU 0 to CPUs 2:
> spi_master spi2: spi2.1: timeout transferring 4 bytes@100000Hz for
> 110(100)ms
> spidev spi2.1: SPI transfer failed: -110
>
> Fix it.
>
You should add Fixes tag here.
> Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
> ---
> drivers/net/ethernet/allwinner/sun4i-emac.c | 15 ++++++++++-----
> 1 file changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c
> b/drivers/net/ethernet/allwinner/sun4i-emac.c index
> 49759deeed8e..d49c2c18f39d 100644
> --- a/drivers/net/ethernet/allwinner/sun4i-emac.c
> +++ b/drivers/net/ethernet/allwinner/sun4i-emac.c
> @@ -378,14 +378,11 @@ static int emac_set_mac_address(struct net_device
> *dev, void *p) }
>
> /* Initialize emac board */
> -static void emac_init_device(struct net_device *dev)
> +static void emac_init_device_without_lock(struct net_device *dev)
Maybe "emac_init_device_no_lock"? _no_lock suffix is often used in such cases.
Best regards,
Jernej
> {
> struct emac_board_info *db = netdev_priv(dev);
> - unsigned long flags;
> unsigned int reg_val;
>
> - spin_lock_irqsave(&db->lock, flags);
> -
> emac_update_speed(dev);
> emac_update_duplex(dev);
>
> @@ -398,7 +395,15 @@ static void emac_init_device(struct net_device *dev)
> reg_val = readl(db->membase + EMAC_INT_CTL_REG);
> reg_val |= (0xf << 0) | (0x01 << 8);
> writel(reg_val, db->membase + EMAC_INT_CTL_REG);
> +}
> +
> +static void emac_init_device(struct net_device *dev)
> +{
> + struct emac_board_info *db = netdev_priv(dev);
> + unsigned long flags;
>
> + spin_lock_irqsave(&db->lock, flags);
> + emac_init_device_without_lock(dev);
> spin_unlock_irqrestore(&db->lock, flags);
> }
>
> @@ -416,7 +421,7 @@ static void emac_timeout(struct net_device *dev,
> unsigned int txqueue)
>
> netif_stop_queue(dev);
> emac_reset(db);
> - emac_init_device(dev);
> + emac_init_device_without_lock(dev);
> /* We can accept TX packets again */
> netif_trans_update(dev);
> netif_wake_queue(dev);
> --
> 2.25.1
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-08-30 3:32 [PATCH] net: allwinner: emac: Fix double spinlock in emac_timeout qianfanguijin
2022-09-06 20:54 ` Jernej Škrabec
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