On 18/01/19 8:49 AM, Darwin Dingel wrote: > 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 >
Adding Colin and Dan. Regards, Darwin
