serial: amba-pl011: Make sure we initialize the port.lock spinlock
PATCH v2 1/1 serial: amba-pl011: Make sure we initialize the port.lock spinlock
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.
---
v2: Added extra context in the commit message
--- drivers/tty/serial/amba-pl011.c | 1 + 1 file changed, 1 insertion(+)
drivers/tty/serial/amba-pl011.c +1 -0
@@ -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;
Signature · 1 line
2.17.1
Quoted 41 lines · John Stultz
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+0x10/0x1cWhich 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.
Quoted 7 lines
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!
Thanks to both of you, John & Andy.
Quoted 26 lines
Cc Valentin Schneider <[email protected]>Cc Andy Shevchenko <[email protected]>Cc Russell King <[email protected]>Cc Greg Kroah-Hartman <[email protected]>Cc Jiri Slaby <[email protected]>Reported-by Valentin Schneider <[email protected]>Reviewed-by Andy Shevchenko <[email protected]>Signed-off-by John Stultz <[email protected]>---
v2: Added extra context in the commit message--- drivers/tty/serial/amba-pl011.c | 1 + 1 file changed, 1 insertion(+)drivers/tty/serial/amba-pl011.c +1
-0@@ -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;