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serial: pl011: Fix oops on -EPROBE_DEFER 

commit 27afac93e3 upstream.

If probing of a pl011 gets deferred until after free_initmem(), an oops
ensues because pl011_console_match() is called which has been freed.

Fix by removing the __init attribute from the function and those it
calls.

Commit 10879ae5f1 ("serial: pl011: add console matching function")
introduced pl011_console_match() not just for early consoles but
regular preferred consoles, such as those added by acpi_parse_spcr().
Regular consoles may be registered after free_initmem() for various
reasons, one being deferred probing, another being dynamic enablement
of serial ports using a DeviceTree overlay.

Thus, pl011_console_match() must not be declared __init and the
functions it calls mustn't either.

Stack trace for posterity:

Unable to handle kernel paging request at virtual address 80c38b58
Internal error: Oops: 8000000d [#1] PREEMPT SMP ARM
PC is at pl011_console_match+0x0/0xfc
LR is at register_console+0x150/0x468
[<80187004>] (register_console)
[<805a8184>] (uart_add_one_port)
[<805b2b68>] (pl011_register_port)
[<805b3ce4>] (pl011_probe)
[<80569214>] (amba_probe)
[<805ca088>] (really_probe)
[<805ca2ec>] (driver_probe_device)
[<805ca5b0>] (__device_attach_driver)
[<805c8060>] (bus_for_each_drv)
[<805c9dfc>] (__device_attach)
[<805ca630>] (device_initial_probe)
[<805c90a8>] (bus_probe_device)
[<805c95a8>] (deferred_probe_work_func)

Fixes: 10879ae5f1 ("serial: pl011: add console matching function")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v4.10+
Cc: Aleksey Makarov <amakarov@marvell.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Christopher Covington <cov@codeaurora.org>
Link: https://lore.kernel.org/r/f827ff09da55b8c57d316a1b008a137677b58921.1597315557.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Lukas Wunner 2020-08-13 12:52:40 +02:00 committed by Greg Kroah-Hartman
parent daae6b962a
commit 0806b49bba
1 changed files with 5 additions and 6 deletions
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11
drivers/tty/serial/amba-pl011.c
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@ -2252,9 +2252,8 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
clk_disable(uap->clk);
}
static void __init
pl011_console_get_options(struct uart_amba_port *uap, int *baud,
int *parity, int *bits)
static void pl011_console_get_options(struct uart_amba_port *uap, int *baud,
int *parity, int *bits)
{
if (pl011_read(uap, REG_CR) & UART01x_CR_UARTEN) {
unsigned int lcr_h, ibrd, fbrd;
@ -2287,7 +2286,7 @@ pl011_console_get_options(struct uart_amba_port *uap, int *baud,
}
}
static int __init pl011_console_setup(struct console *co, char *options)
static int pl011_console_setup(struct console *co, char *options)
{
struct uart_amba_port *uap;
int baud = 38400;
@ -2355,8 +2354,8 @@ static int __init pl011_console_setup(struct console *co, char *options)
*
* Returns 0 if console matches; otherwise non-zero to use default matching
*/
static int __init pl011_console_match(struct console *co, char *name, int idx,
char *options)
static int pl011_console_match(struct console *co, char *name, int idx,
char *options)
{
unsigned char iotype;
resource_size_t addr;