From: He Zhe zhe.he@windriver.com
[ Upstream commit 352c4cf40c4a7d439fa5d30aa2160f54b394da82 ]
The initialization code of interrupt backoff work might reference NULL pointer and cause the following crash, if no port was found.
[ 10.017727] CPU 0 Unable to handle kernel paging request at virtual address 000001b0, epc == 807088e0, ra == 8070863c ---- snip ---- [ 11.704470] [<807088e0>] serial8250_register_8250_port+0x318/0x4ac [ 11.747251] [<80708d74>] serial8250_probe+0x148/0x1c0 [ 11.789301] [<80728450>] platform_drv_probe+0x40/0x94 [ 11.830515] [<807264f8>] really_probe+0xf8/0x318 [ 11.870876] [<80726b7c>] __driver_attach+0x110/0x12c [ 11.910960] [<80724374>] bus_for_each_dev+0x78/0xcc [ 11.951134] [<80725958>] bus_add_driver+0x200/0x234 [ 11.989756] [<807273d8>] driver_register+0x84/0x148 [ 12.029832] [<80d72f84>] serial8250_init+0x138/0x198 [ 12.070447] [<80100e6c>] do_one_initcall+0x5c/0x2a0 [ 12.110104] [<80d3a208>] kernel_init_freeable+0x370/0x484 [ 12.150722] [<80a49420>] kernel_init+0x10/0xf8 [ 12.191517] [<8010756c>] ret_from_kernel_thread+0x14/0x1c
This patch makes sure the initialization code can be reached only if a port is found.
Fixes: 6d7f677a2afa ("serial: 8250: Rate limit serial port rx interrupts during input overruns") Signed-off-by: He Zhe zhe.he@windriver.com Reviewed-by: Darwin Dingel darwin.dingel@alliedtelesis.co.nz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/8250/8250_core.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 0e65d4261f94c..69aaee5d7fe14 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -1074,15 +1074,16 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
ret = 0; } - }
- /* Initialise interrupt backoff work if required */ - if (up->overrun_backoff_time_ms > 0) { - uart->overrun_backoff_time_ms = up->overrun_backoff_time_ms; - INIT_DELAYED_WORK(&uart->overrun_backoff, - serial_8250_overrun_backoff_work); - } else { - uart->overrun_backoff_time_ms = 0; + /* Initialise interrupt backoff work if required */ + if (up->overrun_backoff_time_ms > 0) { + uart->overrun_backoff_time_ms = + up->overrun_backoff_time_ms; + INIT_DELAYED_WORK(&uart->overrun_backoff, + serial_8250_overrun_backoff_work); + } else { + uart->overrun_backoff_time_ms = 0; + } }
mutex_unlock(&serial_mutex);