diff options
| author | He Zhe <zhe.he@windriver.com> | 2019-01-17 17:00:19 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-18 13:03:47 +0100 |
| commit | 352c4cf40c4a7d439fa5d30aa2160f54b394da82 (patch) | |
| tree | 73bd19b57eeae40f8bf8cd342b740e0ecda72b61 /drivers/tty | |
| parent | aff9cf5955185d1f183227e46c5f8673fa483813 (diff) | |
| download | lwn-352c4cf40c4a7d439fa5d30aa2160f54b394da82.tar.gz lwn-352c4cf40c4a7d439fa5d30aa2160f54b394da82.zip | |
serial: 8250: Fix serial8250 initialization crash
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>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 189ab1212d9a..e441221e04b9 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -1070,15 +1070,16 @@ 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); |