lkml.org 
[lkml]   [2020]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH AUTOSEL 4.19 076/172] serial: amba-pl011: Make sure we initialize the port.lock spinlock
Date
From: John Stultz <john.stultz@linaro.org>

[ Upstream commit 8508f4cba308f785b2fd4b8c38849c117b407297 ]

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: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
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>
Reviewed-and-tested-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/20200428184050.6501-1-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 af21122dfade..1d501154e9f7 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2585,6 +2585,7 @@ static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap,
uap->port.fifosize = uap->fifosize;
uap->port.flags = UPF_BOOT_AUTOCONF;
uap->port.line = index;
+ spin_lock_init(&uap->port.lock);

amba_ports[index] = uap;

--
2.25.1
\
 
 \ /
  Last update: 2020-06-18 04:27    [W:0.426 / U:2.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site