On 17/01/19 10:00 PM, [email protected] wrote: > From: He Zhe <[email protected]> > > 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: commit 6d7f677a2afa ("serial: 8250: Rate limit serial port rx > interrupts during input overruns") > Signed-off-by: He Zhe <[email protected]> > --- > 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 189ab12..e441221 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); >
Reviewed-by: Darwin Dingel <[email protected]> I presume this is the same issue reported here: https://www.spinics.net/lists/linux-serial/msg33114.html https://lkml.org/lkml/2018/12/22/171 Thanks! Regards, Darwin
