* [PATCH v2] serial: amba-pl011: Make sure we initialize the port.lock spinlock
@ 2020-04-28 18:40 John Stultz
2020-04-28 22:18 ` Valentin Schneider
0 siblings, 1 reply; 2+ messages in thread
From: John Stultz @ 2020-04-28 18:40 UTC (permalink / raw)
To: lkml
Cc: John Stultz, Valentin Schneider, Andy Shevchenko, Russell King,
Greg Kroah-Hartman, Jiri Slaby, linux-serial
Valentine reported seeing:
[ 3.626638] INFO: trying to register non-static key.
[ 3.626639] the code is fine but needs lockdep annotation.
[ 3.626640] turning off the locking correctness validator.
[ 3.626644] CPU: 7 PID: 51 Comm: kworker/7:1 Not tainted 5.7.0-rc2-00115-g8c2e9790f196 #116
[ 3.626646] Hardware name: HiKey960 (DT)
[ 3.626656] Workqueue: events deferred_probe_work_func
[ 3.632476] sd 0:0:0:0: [sda] Optimal transfer size 8192 bytes not a multiple of physical block size (16384 bytes)
[ 3.640220] Call trace:
[ 3.640225] dump_backtrace+0x0/0x1b8
[ 3.640227] show_stack+0x20/0x30
[ 3.640230] dump_stack+0xec/0x158
[ 3.640234] register_lock_class+0x598/0x5c0
[ 3.640235] __lock_acquire+0x80/0x16c0
[ 3.640236] lock_acquire+0xf4/0x4a0
[ 3.640241] _raw_spin_lock_irqsave+0x70/0xa8
[ 3.640245] uart_add_one_port+0x388/0x4b8
[ 3.640248] pl011_register_port+0x70/0xf0
[ 3.640250] pl011_probe+0x184/0x1b8
[ 3.640254] amba_probe+0xdc/0x180
[ 3.640256] really_probe+0xe0/0x338
[ 3.640257] driver_probe_device+0x60/0xf8
[ 3.640259] __device_attach_driver+0x8c/0xd0
[ 3.640260] bus_for_each_drv+0x84/0xd8
[ 3.640261] __device_attach+0xe4/0x140
[ 3.640263] device_initial_probe+0x1c/0x28
[ 3.640265] bus_probe_device+0xa4/0xb0
[ 3.640266] deferred_probe_work_func+0x7c/0xb8
[ 3.640269] process_one_work+0x2c0/0x768
[ 3.640271] worker_thread+0x4c/0x498
[ 3.640272] kthread+0x14c/0x158
[ 3.640275] ret_from_fork+0x10/0x1c
Which seems to be due to the fact that after allocating the uap
structure, nothing initializes the spinlock.
Its a little confusing, as uart_port_spin_lock_init() is one
place where the lock is supposed to be initialized, but it has
an exception for the case where the port is a console.
This makes it seem like a deeper fix is needed to properly
register the console, but I'm not sure what that entails, and
Andy suggested that this approach is less invasive.
Thus, this patch resolves the issue by initializing the spinlock
in the driver, and resolves the resulting warning.
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Reported-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v2: Added extra context in the commit message
---
drivers/tty/serial/amba-pl011.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 2296bb0f9578..458fc3d9d48c 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2575,6 +2575,7 @@ static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap,
uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL011_CONSOLE);
uap->port.flags = UPF_BOOT_AUTOCONF;
uap->port.line = index;
+ spin_lock_init(&uap->port.lock);
amba_ports[index] = uap;
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] serial: amba-pl011: Make sure we initialize the port.lock spinlock
2020-04-28 18:40 [PATCH v2] serial: amba-pl011: Make sure we initialize the port.lock spinlock John Stultz
@ 2020-04-28 22:18 ` Valentin Schneider
0 siblings, 0 replies; 2+ messages in thread
From: Valentin Schneider @ 2020-04-28 22:18 UTC (permalink / raw)
To: John Stultz
Cc: lkml, Andy Shevchenko, Russell King, Greg Kroah-Hartman,
Jiri Slaby, linux-serial
On 28/04/20 19:40, John Stultz wrote:
> Valentine reported seeing:
>
> [ 3.626638] INFO: trying to register non-static key.
> [ 3.626639] the code is fine but needs lockdep annotation.
> [ 3.626640] turning off the locking correctness validator.
> [ 3.626644] CPU: 7 PID: 51 Comm: kworker/7:1 Not tainted 5.7.0-rc2-00115-g8c2e9790f196 #116
> [ 3.626646] Hardware name: HiKey960 (DT)
> [ 3.626656] Workqueue: events deferred_probe_work_func
> [ 3.632476] sd 0:0:0:0: [sda] Optimal transfer size 8192 bytes not a multiple of physical block size (16384 bytes)
> [ 3.640220] Call trace:
> [ 3.640225] dump_backtrace+0x0/0x1b8
> [ 3.640227] show_stack+0x20/0x30
> [ 3.640230] dump_stack+0xec/0x158
> [ 3.640234] register_lock_class+0x598/0x5c0
> [ 3.640235] __lock_acquire+0x80/0x16c0
> [ 3.640236] lock_acquire+0xf4/0x4a0
> [ 3.640241] _raw_spin_lock_irqsave+0x70/0xa8
> [ 3.640245] uart_add_one_port+0x388/0x4b8
> [ 3.640248] pl011_register_port+0x70/0xf0
> [ 3.640250] pl011_probe+0x184/0x1b8
> [ 3.640254] amba_probe+0xdc/0x180
> [ 3.640256] really_probe+0xe0/0x338
> [ 3.640257] driver_probe_device+0x60/0xf8
> [ 3.640259] __device_attach_driver+0x8c/0xd0
> [ 3.640260] bus_for_each_drv+0x84/0xd8
> [ 3.640261] __device_attach+0xe4/0x140
> [ 3.640263] device_initial_probe+0x1c/0x28
> [ 3.640265] bus_probe_device+0xa4/0xb0
> [ 3.640266] deferred_probe_work_func+0x7c/0xb8
> [ 3.640269] process_one_work+0x2c0/0x768
> [ 3.640271] worker_thread+0x4c/0x498
> [ 3.640272] kthread+0x14c/0x158
> [ 3.640275] ret_from_fork+0x10/0x1c
>
> Which seems to be due to the fact that after allocating the uap
> structure, nothing initializes the spinlock.
>
> Its a little confusing, as uart_port_spin_lock_init() is one
> place where the lock is supposed to be initialized, but it has
> an exception for the case where the port is a console.
>
> This makes it seem like a deeper fix is needed to properly
> register the console, but I'm not sure what that entails, and
> Andy suggested that this approach is less invasive.
>
> Thus, this patch resolves the issue by initializing the spinlock
> in the driver, and resolves the resulting warning.
>
Agreed with all of the above!
Reviewed-and-tested-by: Valentin Schneider <valentin.schneider@arm.com>
Thanks to both of you, John & Andy.
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Jiri Slaby <jslaby@suse.com>
> Cc: linux-serial@vger.kernel.org
> Reported-by: Valentin Schneider <valentin.schneider@arm.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
> v2: Added extra context in the commit message
> ---
> drivers/tty/serial/amba-pl011.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index 2296bb0f9578..458fc3d9d48c 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -2575,6 +2575,7 @@ static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap,
> uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL011_CONSOLE);
> uap->port.flags = UPF_BOOT_AUTOCONF;
> uap->port.line = index;
> + spin_lock_init(&uap->port.lock);
>
> amba_ports[index] = uap;
^ permalink raw reply [flat|nested] 2+ messages in thread
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