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authorKrzysztof Kozlowski <k.kozlowski@samsung.com>2016-06-16 08:27:35 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-08-20 18:09:17 +0200
commit8af97d26ce2054f4914eb382be2ab1d7c994b190 (patch)
tree8dcaa9a7225a3da376dc75e9747b9e4bcb3a4bc8 /drivers/tty
parent79b8ddbebf7420fa71c76d4f5f892b21ef1e4456 (diff)
serial: samsung: Fix ERR pointer dereference on deferred probe
commit e51e4d8a185de90424b03f30181b35f29c46a25a upstream. When the clk_get() of "uart" clock returns EPROBE_DEFER, the next re-probe finishes with success but uses invalid (ERR_PTR) values. This leads to dereferencing of ERR_PTR stored under ourport->clk: 12c30000.serial: Controller clock not found (...) 12c30000.serial: ttySAC3 at MMIO 0x12c30000 (irq = 61, base_baud = 0) is a S3C6400/10 Unable to handle kernel paging request at virtual address fffffdfb (clk_prepare) from [<c039f7d0>] (s3c24xx_serial_pm+0x20/0x128) (s3c24xx_serial_pm) from [<c0395414>] (uart_change_pm+0x38/0x40) (uart_change_pm) from [<c039689c>] (uart_add_one_port+0x31c/0x44c) (uart_add_one_port) from [<c03a035c>] (s3c24xx_serial_probe+0x2a8/0x418) (s3c24xx_serial_probe) from [<c03ee110>] (platform_drv_probe+0x50/0xb0) (platform_drv_probe) from [<c03ecb44>] (driver_probe_device+0x1f4/0x2b0) (driver_probe_device) from [<c03eb0c0>] (bus_for_each_drv+0x44/0x8c) (bus_for_each_drv) from [<c03ec8c8>] (__device_attach+0x9c/0x100) (__device_attach) from [<c03ebf54>] (bus_probe_device+0x84/0x8c) (bus_probe_device) from [<c03ec388>] (deferred_probe_work_func+0x60/0x8c) (deferred_probe_work_func) from [<c012fee4>] (process_one_work+0x120/0x328) (process_one_work) from [<c0130150>] (worker_thread+0x2c/0x4ac) (worker_thread) from [<c0135320>] (kthread+0xd8/0xf4) (kthread) from [<c0107978>] (ret_from_fork+0x14/0x3c) The first unsuccessful clk_get() causes s3c24xx_serial_init_port() to exit with failure but the s3c24xx_uart_port is left half-configured (e.g. port->mapbase is set, clk contains ERR_PTR). On next re-probe, the function s3c24xx_serial_init_port() will exit early with success because of configured port->mapbase and driver will use old values, including the ERR_PTR as clock. Fix this by cleaning the port->mapbase on error path so each re-probe will initialize all of the port settings. Fixes: 60e93575476f ("serial: samsung: enable clock before clearing pending interrupts during init") Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com> Tested-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/samsung.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index 8320173af846..237ef5573c18 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1676,7 +1676,7 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
return -ENODEV;
if (port->mapbase != 0)
- return 0;
+ return -EINVAL;
/* setup info for port */
port->dev = &platdev->dev;
@@ -1730,22 +1730,25 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
ourport->dma = devm_kzalloc(port->dev,
sizeof(*ourport->dma),
GFP_KERNEL);
- if (!ourport->dma)
- return -ENOMEM;
+ if (!ourport->dma) {
+ ret = -ENOMEM;
+ goto err;
+ }
}
ourport->clk = clk_get(&platdev->dev, "uart");
if (IS_ERR(ourport->clk)) {
pr_err("%s: Controller clock not found\n",
dev_name(&platdev->dev));
- return PTR_ERR(ourport->clk);
+ ret = PTR_ERR(ourport->clk);
+ goto err;
}
ret = clk_prepare_enable(ourport->clk);
if (ret) {
pr_err("uart: clock failed to prepare+enable: %d\n", ret);
clk_put(ourport->clk);
- return ret;
+ goto err;
}
/* Keep all interrupts masked and cleared */
@@ -1761,7 +1764,12 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
/* reset the fifos (and setup the uart) */
s3c24xx_serial_resetport(port, cfg);
+
return 0;
+
+err:
+ port->mapbase = 0;
+ return ret;
}
/* Device driver serial port probe */