atmel_serial: fix spinlock lockup in RS485 code

PATCH In review Claudio Scordino 4 participants 6 messages Dec 15, 2011 – Dec 16, 2011

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Stable branch TTY layer and serial drivers Arm/Microchip (AT91) SoC support Microchip AT91 serial driver

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Claudio Scordino

author

2011-12-15 08:47 UTC #0 lore raw

PATCH 1/1 atmel_serial: fix spinlock lockup in RS485 code

Hi all.

We have encountered a spinlock lockup in the RS485 part of the atmel_serial driver.

Here is the trace:

[   68.030000] BUG: spinlock lockup on CPU#0, dnp_master/244, c07e82c0
[   68.040000] [<c002a790>] (unwind_backtrace+0x0/0xf0) from [<c012f8f0>] (do_raw_spin_lock+0x10c/0x148)
[   68.050000] [<c012f8f0>] (do_raw_spin_lock+0x10c/0x148) from [<c015152c>] (atmel_tasklet_func+0x10/0x708)
[   68.060000] [<c015152c>] (atmel_tasklet_func+0x10/0x708) from [<c003bfd4>] (tasklet_action+0x8c/0xf4)
[   68.070000] [<c003bfd4>] (tasklet_action+0x8c/0xf4) from [<c003c630>] (__do_softirq+0xa4/0x180)
[   68.080000] [<c003c630>] (__do_softirq+0xa4/0x180) from [<c003c764>] (irq_exit+0x58/0xb0)
[   68.090000] [<c003c764>] (irq_exit+0x58/0xb0) from [<c0021084>] (asm_do_IRQ+0x84/0xa4)
[   68.100000] [<c0021084>] (asm_do_IRQ+0x84/0xa4) from [<c002622c>] (__irq_svc+0x4c/0x98)
[   68.110000] Exception stack(0xc341fdc8 to 0xc341fe10)
[   68.110000] fdc0:                   c07e82c0 00000000 00000200 c4818000 c341fe10 c07e82c0
[   68.120000] fde0: 00000000 c07e82c0 c38d3318 c341e000 bebcee00 010a0b60 c07e83fc c341fe10
[   68.130000] fe00: c0151d54 c023d9c0 60000013 ffffffff
[   68.140000] [<c002622c>] (__irq_svc+0x4c/0x98) from [<c023d9c0>] (_raw_spin_unlock+0x0/0x48)
[   68.140000] [<c023d9c0>] (_raw_spin_unlock+0x0/0x48) from [<00000000>] (  (null))

The soft lockup occurs later

[  126.750000] BUG: soft lockup - CPU#0 stuck for 61s! [dnp_master:244]
[  126.750000] irq event stamp: 0
[  126.750000] hardirqs last  enabled at (0): [<  (null)>]   (null)
[  126.750000] hardirqs last disabled at (0): [<c0035e30>] copy_process+0x308/0xe78
[  126.750000] softirqs last  enabled at (0): [<c0035e30>] copy_process+0x308/0xe78
[  126.750000] softirqs last disabled at (0): [<  (null)>]   (null)

The following patch (already tested by Dave, who also reported the bug) fixes the problem.

Regards,

Claudio

Subject: atmel_serial: fix spinlock lockup in RS485 code

Patch to fix a spinlock lockup in the driver that sometimes happens when the tasklet starts.

Signed-off-by Claudio Scordino <[email protected]>

Signed-off-by Dave Bender <[email protected]>

Tested-by Dave Bender <[email protected]>

---
 drivers/tty/serial/atmel_serial.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

drivers/tty/serial/atmel_serial.c +3 -2

index 4c823f3..90c8e3a 100644
@@ -212,8 +212,9 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	unsigned int mode;
+	unsigned long flags;
 
-	spin_lock(&port->lock);
+	spin_lock_irqsave(&port->lock, flags);
 
 	/* Disable interrupts */
 	UART_PUT_IDR(port, atmel_port->tx_done_mask);

@@ -244,7 +245,7 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 	/* Enable interrupts */
 	UART_PUT_IER(port, atmel_port->tx_done_mask);
 
-	spin_unlock(&port->lock);
+	spin_unlock_irqrestore(&port->lock, flags);
 
 }

Signature · 1 line

1.7.1

Nicolas Ferre

Acked-by on v1 1/1

2011-12-15 10:00 UTC #1 lore raw

On 12/15/2011 09:47 AM, Claudio Scordino :

Quoted 57 lines

Hi all.

We have encountered a spinlock lockup in the RS485 part of the atmel_serial driver.

Here is the trace:

[   68.030000] BUG: spinlock lockup on CPU#0, dnp_master/244, c07e82c0
[   68.040000] [<c002a790>] (unwind_backtrace+0x0/0xf0) from
[<c012f8f0>] (do_raw_spin_lock+0x10c/0x148)
[   68.050000] [<c012f8f0>] (do_raw_spin_lock+0x10c/0x148) from
[<c015152c>] (atmel_tasklet_func+0x10/0x708)
[   68.060000] [<c015152c>] (atmel_tasklet_func+0x10/0x708) from
[<c003bfd4>] (tasklet_action+0x8c/0xf4)
[   68.070000] [<c003bfd4>] (tasklet_action+0x8c/0xf4) from [<c003c630>]
(__do_softirq+0xa4/0x180)
[   68.080000] [<c003c630>] (__do_softirq+0xa4/0x180) from [<c003c764>]
(irq_exit+0x58/0xb0)
[   68.090000] [<c003c764>] (irq_exit+0x58/0xb0) from [<c0021084>]
(asm_do_IRQ+0x84/0xa4)
[   68.100000] [<c0021084>] (asm_do_IRQ+0x84/0xa4) from [<c002622c>]
(__irq_svc+0x4c/0x98)
[   68.110000] Exception stack(0xc341fdc8 to 0xc341fe10)
[   68.110000] fdc0:                   c07e82c0 00000000 00000200
c4818000 c341fe10 c07e82c0
[   68.120000] fde0: 00000000 c07e82c0 c38d3318 c341e000 bebcee00
010a0b60 c07e83fc c341fe10
[   68.130000] fe00: c0151d54 c023d9c0 60000013 ffffffff
[   68.140000] [<c002622c>] (__irq_svc+0x4c/0x98) from [<c023d9c0>]
(_raw_spin_unlock+0x0/0x48)
[   68.140000] [<c023d9c0>] (_raw_spin_unlock+0x0/0x48) from

[<00000000>] ( (null))

The soft lockup occurs later

[  126.750000] BUG: soft lockup - CPU#0 stuck for 61s! [dnp_master:244]
[  126.750000] irq event stamp: 0
[  126.750000] hardirqs last  enabled at (0): [<  (null)>]   (null)
[  126.750000] hardirqs last disabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last  enabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last disabled at (0): [<  (null)>]   (null)

The following patch (already tested by Dave, who also reported the bug) fixes the problem.

Regards,

Claudio

Subject: atmel_serial: fix spinlock lockup in RS485 code

Quoted 7 lines

Patch to fix a spinlock lockup in the driver that sometimes happens when the
tasklet starts.
Signed-off-by Claudio Scordino <[email protected]>
Signed-off-by Dave Bender <[email protected]>
Tested-by Dave Bender <[email protected]>

Acked-by Nicolas Ferre <[email protected]>

Claudio, can you please send the patch to Alan with my "Acked-by" and an addition to Linux stable just after the signature lines:

Cc stable <[email protected]>

Thanks, best regards,

Quoted 31 lines

---
 drivers/tty/serial/atmel_serial.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

drivers/tty/serial/atmel_serial.c +2 -1

index 4c823f3..90c8e3a 100644
@@ -212,8 +212,9 @@ void atmel_config_rs485(struct uart_port *port,
 struct serial_rs485 *rs485conf)
 {
     struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
     unsigned int mode;
+    unsigned long flags;
 
-    spin_lock(&port->lock);
+    spin_lock_irqsave(&port->lock, flags);
 
     /* Disable interrupts */

     UART_PUT_IDR(port, atmel_port->tx_done_mask);

drivers/tty/serial/atmel_serial.c +1 -1

@@ -244,7 +245,7 @@ void atmel_config_rs485(struct uart_port *port,
 struct serial_rs485 *rs485conf)
     /* Enable interrupts */
     UART_PUT_IER(port, atmel_port->tx_done_mask);
 
-    spin_unlock(&port->lock);
+    spin_unlock_irqrestore(&port->lock, flags);
 
 }

Signature · 1 line

Nicolas Ferre

Claudio Scordino

author Tested-by Dave Bender Acked-by Nicolas Ferre Acked-by Alan Cox

2011-12-15 11:04 UTC #2 lore raw

Il 15/12/2011 11:00, Nicolas Ferre ha scritto:

Quoted 66 lines

On 12/15/2011 09:47 AM, Claudio Scordino :

Quoted 57 lines

Hi all.

We have encountered a spinlock lockup in the RS485 part of the atmel_serial driver.

Here is the trace:

[   68.030000] BUG: spinlock lockup on CPU#0, dnp_master/244, c07e82c0
[   68.040000] [<c002a790>] (unwind_backtrace+0x0/0xf0) from
[<c012f8f0>] (do_raw_spin_lock+0x10c/0x148)
[   68.050000] [<c012f8f0>] (do_raw_spin_lock+0x10c/0x148) from
[<c015152c>] (atmel_tasklet_func+0x10/0x708)
[   68.060000] [<c015152c>] (atmel_tasklet_func+0x10/0x708) from
[<c003bfd4>] (tasklet_action+0x8c/0xf4)
[   68.070000] [<c003bfd4>] (tasklet_action+0x8c/0xf4) from [<c003c630>]
(__do_softirq+0xa4/0x180)
[   68.080000] [<c003c630>] (__do_softirq+0xa4/0x180) from [<c003c764>]
(irq_exit+0x58/0xb0)
[   68.090000] [<c003c764>] (irq_exit+0x58/0xb0) from [<c0021084>]
(asm_do_IRQ+0x84/0xa4)
[   68.100000] [<c0021084>] (asm_do_IRQ+0x84/0xa4) from [<c002622c>]
(__irq_svc+0x4c/0x98)
[   68.110000] Exception stack(0xc341fdc8 to 0xc341fe10)
[   68.110000] fdc0:                   c07e82c0 00000000 00000200
c4818000 c341fe10 c07e82c0
[   68.120000] fde0: 00000000 c07e82c0 c38d3318 c341e000 bebcee00
010a0b60 c07e83fc c341fe10
[   68.130000] fe00: c0151d54 c023d9c0 60000013 ffffffff
[   68.140000] [<c002622c>] (__irq_svc+0x4c/0x98) from [<c023d9c0>]
(_raw_spin_unlock+0x0/0x48)
[   68.140000] [<c023d9c0>] (_raw_spin_unlock+0x0/0x48) from

[<00000000>] ( (null))

The soft lockup occurs later

[  126.750000] BUG: soft lockup - CPU#0 stuck for 61s! [dnp_master:244]
[  126.750000] irq event stamp: 0
[  126.750000] hardirqs last  enabled at (0): [<   (null)>]   (null)
[  126.750000] hardirqs last disabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last  enabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last disabled at (0): [<   (null)>]   (null)

The following patch (already tested by Dave, who also reported the bug) fixes the problem.

Regards,

Claudio

Subject: atmel_serial: fix spinlock lockup in RS485 code

Quoted 7 lines

Patch to fix a spinlock lockup in the driver that sometimes happens when the
tasklet starts.
Signed-off-by Claudio Scordino<[email protected]>
Signed-off-by Dave Bender<[email protected]>
Tested-by Dave Bender<[email protected]>

Quoted 6 lines

Acked-by Nicolas Ferre<[email protected]>
Claudio, can you please send the patch to Alan with my "Acked-by" and an addition to Linux stable just after the signature lines:
Cc stable<[email protected]>

Dear Alan,

here is the patch with all the acked-bys.

Many thanks,

Claudio

Subject: atmel_serial: fix spinlock lockup in RS485 code

Patch to fix a spinlock lockup in the driver that sometimes happens when the tasklet starts.

Signed-off-by Claudio Scordino <[email protected]>

Signed-off-by Dave Bender <[email protected]>

Tested-by Dave Bender <[email protected]>

Acked-by Nicolas Ferre <[email protected]>

Acked-by Alan Cox <[email protected]>

Cc stable <[email protected]>

---
 drivers/tty/serial/atmel_serial.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

drivers/tty/serial/atmel_serial.c +3 -2

index 4c823f3..90c8e3a 100644
@@ -212,8 +212,9 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	unsigned int mode;
+	unsigned long flags;
 
-	spin_lock(&port->lock);
+	spin_lock_irqsave(&port->lock, flags);
 
 	/* Disable interrupts */
 	UART_PUT_IDR(port, atmel_port->tx_done_mask);

@@ -244,7 +245,7 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 	/* Enable interrupts */
 	UART_PUT_IER(port, atmel_port->tx_done_mask);
 
-	spin_unlock(&port->lock);
+	spin_unlock_irqrestore(&port->lock, flags);
 
 }

Signature · 1 line

1.7.1

Greg KH

2011-12-15 19:03 UTC #3 lore raw

Quoted 73 lines · Claudio Scordino

Il 15/12/2011 11:00, Nicolas Ferre ha scritto:
Quoted 72 lines
On 12/15/2011 09:47 AM, Claudio Scordino :
Quoted 57 lines
Hi all.
We have encountered a spinlock lockup in the RS485 part of the atmel_serial driver.
Here is the trace:
[   68.030000] BUG: spinlock lockup on CPU#0, dnp_master/244, c07e82c0
[   68.040000] [<c002a790>] (unwind_backtrace+0x0/0xf0) from
[<c012f8f0>] (do_raw_spin_lock+0x10c/0x148)
[   68.050000] [<c012f8f0>] (do_raw_spin_lock+0x10c/0x148) from
[<c015152c>] (atmel_tasklet_func+0x10/0x708)
[   68.060000] [<c015152c>] (atmel_tasklet_func+0x10/0x708) from
[<c003bfd4>] (tasklet_action+0x8c/0xf4)
[   68.070000] [<c003bfd4>] (tasklet_action+0x8c/0xf4) from [<c003c630>]
(__do_softirq+0xa4/0x180)
[   68.080000] [<c003c630>] (__do_softirq+0xa4/0x180) from [<c003c764>]
(irq_exit+0x58/0xb0)
[   68.090000] [<c003c764>] (irq_exit+0x58/0xb0) from [<c0021084>]
(asm_do_IRQ+0x84/0xa4)
[   68.100000] [<c0021084>] (asm_do_IRQ+0x84/0xa4) from [<c002622c>]
(__irq_svc+0x4c/0x98)
[   68.110000] Exception stack(0xc341fdc8 to 0xc341fe10)
[   68.110000] fdc0:                   c07e82c0 00000000 00000200
c4818000 c341fe10 c07e82c0
[   68.120000] fde0: 00000000 c07e82c0 c38d3318 c341e000 bebcee00
010a0b60 c07e83fc c341fe10
[   68.130000] fe00: c0151d54 c023d9c0 60000013 ffffffff
[   68.140000] [<c002622c>] (__irq_svc+0x4c/0x98) from [<c023d9c0>]
(_raw_spin_unlock+0x0/0x48)
[   68.140000] [<c023d9c0>] (_raw_spin_unlock+0x0/0x48) from
[<00000000>] ( (null))
The soft lockup occurs later
[  126.750000] BUG: soft lockup - CPU#0 stuck for 61s! [dnp_master:244]
[  126.750000] irq event stamp: 0
[  126.750000] hardirqs last  enabled at (0): [<   (null)>]   (null)
[  126.750000] hardirqs last disabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last  enabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last disabled at (0): [<   (null)>]   (null)
The following patch (already tested by Dave, who also reported the bug) fixes the problem.
Regards,
Claudio
Subject: atmel_serial: fix spinlock lockup in RS485 code
Quoted 7 lines
Patch to fix a spinlock lockup in the driver that sometimes happens when the
tasklet starts.
Signed-off-by Claudio Scordino<[email protected]>
Signed-off-by Dave Bender<[email protected]>
Tested-by Dave Bender<[email protected]>
Acked-by Nicolas Ferre<[email protected]>
Claudio, can you please send the patch to Alan with my "Acked-by" and an addition to Linux stable just after the signature lines:
Cc stable<[email protected]>

That address has been invalid since August, please use [email protected] now.

Quoted 3 lines

Dear Alan,
here is the patch with all the acked-bys.

I'll take care of this.

thanks,

greg k-h

Claudio Scordino

author Tested-by Dave Bender Acked-by Nicolas Ferre Acked-by Alan Cox

2011-12-16 14:08 UTC #4 lore raw

Il 15/12/2011 19:58, Greg KH ha scritto:

Quoted 70 lines · Claudio Scordino

Quoted 69 lines
Il 15/12/2011 11:00, Nicolas Ferre ha scritto:
Quoted 68 lines
On 12/15/2011 09:47 AM, Claudio Scordino :
Quoted 57 lines
Hi all.
We have encountered a spinlock lockup in the RS485 part of the atmel_serial driver.
Here is the trace:
[   68.030000] BUG: spinlock lockup on CPU#0, dnp_master/244, c07e82c0
[   68.040000] [<c002a790>] (unwind_backtrace+0x0/0xf0) from
[<c012f8f0>] (do_raw_spin_lock+0x10c/0x148)
[   68.050000] [<c012f8f0>] (do_raw_spin_lock+0x10c/0x148) from
[<c015152c>] (atmel_tasklet_func+0x10/0x708)
[   68.060000] [<c015152c>] (atmel_tasklet_func+0x10/0x708) from
[<c003bfd4>] (tasklet_action+0x8c/0xf4)
[   68.070000] [<c003bfd4>] (tasklet_action+0x8c/0xf4) from [<c003c630>]
(__do_softirq+0xa4/0x180)
[   68.080000] [<c003c630>] (__do_softirq+0xa4/0x180) from [<c003c764>]
(irq_exit+0x58/0xb0)
[   68.090000] [<c003c764>] (irq_exit+0x58/0xb0) from [<c0021084>]
(asm_do_IRQ+0x84/0xa4)
[   68.100000] [<c0021084>] (asm_do_IRQ+0x84/0xa4) from [<c002622c>]
(__irq_svc+0x4c/0x98)
[   68.110000] Exception stack(0xc341fdc8 to 0xc341fe10)
[   68.110000] fdc0:                   c07e82c0 00000000 00000200
c4818000 c341fe10 c07e82c0
[   68.120000] fde0: 00000000 c07e82c0 c38d3318 c341e000 bebcee00
010a0b60 c07e83fc c341fe10
[   68.130000] fe00: c0151d54 c023d9c0 60000013 ffffffff
[   68.140000] [<c002622c>] (__irq_svc+0x4c/0x98) from [<c023d9c0>]
(_raw_spin_unlock+0x0/0x48)
[   68.140000] [<c023d9c0>] (_raw_spin_unlock+0x0/0x48) from
[<00000000>] ( (null))
The soft lockup occurs later
[  126.750000] BUG: soft lockup - CPU#0 stuck for 61s! [dnp_master:244]
[  126.750000] irq event stamp: 0
[  126.750000] hardirqs last  enabled at (0): [<    (null)>]   (null)
[  126.750000] hardirqs last disabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last  enabled at (0): [<c0035e30>]
copy_process+0x308/0xe78
[  126.750000] softirqs last disabled at (0): [<    (null)>]   (null)
The following patch (already tested by Dave, who also reported the bug) fixes the problem.
Regards,
Claudio
Subject: atmel_serial: fix spinlock lockup in RS485 code
Quoted 7 lines
Patch to fix a spinlock lockup in the driver that sometimes happens when the
tasklet starts.
Signed-off-by Claudio Scordino<[email protected]>
Signed-off-by Dave Bender<[email protected]>
Tested-by Dave Bender<[email protected]>
Acked-by Nicolas Ferre<[email protected]>

Quoted 7 lines

Quoted 4 lines
Quoted 4 lines
Claudio, can you please send the patch to Alan with my "Acked-by" and an addition to Linux stable just after the signature lines:
Cc stable<[email protected]>
That address has been invalid since August, please use [email protected] now.

Hi Greg,

here is the patch with the right address.

Many thanks for taking care of it.

Best regards,

Claudio

Subject: atmel_serial: fix spinlock lockup in RS485 code

Patch to fix a spinlock lockup in the driver that sometimes happens when the tasklet starts.

Signed-off-by Claudio Scordino <[email protected]>

Signed-off-by Dave Bender <[email protected]>

Tested-by Dave Bender <[email protected]>

Acked-by Nicolas Ferre <[email protected]>

Acked-by Alan Cox <[email protected]>

Cc stable <[email protected]>

---
 drivers/tty/serial/atmel_serial.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

drivers/tty/serial/atmel_serial.c +3 -2

index 4c823f3..90c8e3a 100644
@@ -212,8 +212,9 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	unsigned int mode;
+	unsigned long flags;
 
-	spin_lock(&port->lock);
+	spin_lock_irqsave(&port->lock, flags);
 
 	/* Disable interrupts */
 	UART_PUT_IDR(port, atmel_port->tx_done_mask);

@@ -244,7 +245,7 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 	/* Enable interrupts */
 	UART_PUT_IER(port, atmel_port->tx_done_mask);
 
-	spin_unlock(&port->lock);
+	spin_unlock_irqrestore(&port->lock, flags);
 
 }

Signature · 1 line

1.7.1

Alan Cox

Acked-by on v1 1/1

2011-12-15 10:10 UTC #5 lore raw

In reply to Claudio Scordino

Quoted 8 lines · On Thu, 15 Dec 2011 09:47:43 +0100 Claudio Scordino <[email protected]>…

Subject: atmel_serial: fix spinlock lockup in RS485 code
Patch to fix a spinlock lockup in the driver that sometimes happens when the tasklet starts.
Signed-off-by Claudio Scordino <[email protected]>
Signed-off-by Dave Bender <[email protected]>
Tested-by Dave Bender <[email protected]>

Acked-by Alan Cox <[email protected]>