Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-13 Thread Sergey Senozhatsky
Hi Andy, On (20/08/13 21:00), Andy Shevchenko wrote: > That's basically what Sergey (IIRC) proposed in [1]. > (You missed enable_irq() part in above) > > I guess we may try it. Sergey, can you submit a formal patch? OK, let me try. -ss

Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-13 Thread Guenter Roeck
On Thu, Aug 13, 2020 at 09:00:13PM +0300, Andy Shevchenko wrote: > On Thu, Aug 13, 2020 at 10:03:44AM -0700, Guenter Roeck wrote: > > On 8/13/20 8:33 AM, Guenter Roeck wrote: > > > On 8/13/20 7:20 AM, Andy Shevchenko wrote: > > >> On Thu, Aug 13, 2020 at 01:59:48PM +0200, Greg KH wrote: > > >>> On

Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-13 Thread Andy Shevchenko
On Thu, Aug 13, 2020 at 10:03:44AM -0700, Guenter Roeck wrote: > On 8/13/20 8:33 AM, Guenter Roeck wrote: > > On 8/13/20 7:20 AM, Andy Shevchenko wrote: > >> On Thu, Aug 13, 2020 at 01:59:48PM +0200, Greg KH wrote: > >>> On Wed, Aug 12, 2020 at 10:06:29PM -0700, Guenter Roeck wrote: > On Wed,

Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-13 Thread Guenter Roeck
On 8/13/20 8:33 AM, Guenter Roeck wrote: > On 8/13/20 7:20 AM, Andy Shevchenko wrote: >> On Thu, Aug 13, 2020 at 01:59:48PM +0200, Greg KH wrote: >>> On Wed, Aug 12, 2020 at 10:06:29PM -0700, Guenter Roeck wrote: On Wed, Aug 12, 2020 at 08:48:13AM -0700, Guenter Roeck wrote: > Hi, > >>

Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-13 Thread Guenter Roeck
On 8/13/20 7:20 AM, Andy Shevchenko wrote: > On Thu, Aug 13, 2020 at 01:59:48PM +0200, Greg KH wrote: >> On Wed, Aug 12, 2020 at 10:06:29PM -0700, Guenter Roeck wrote: >>> On Wed, Aug 12, 2020 at 08:48:13AM -0700, Guenter Roeck wrote: Hi, crbug.com/1114800 reports a hard lockup due t

Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-13 Thread Andy Shevchenko
On Thu, Aug 13, 2020 at 01:59:48PM +0200, Greg KH wrote: > On Wed, Aug 12, 2020 at 10:06:29PM -0700, Guenter Roeck wrote: > > On Wed, Aug 12, 2020 at 08:48:13AM -0700, Guenter Roeck wrote: > > > Hi, > > > > > > crbug.com/1114800 reports a hard lockup due to circular locking in the > > > 8250 conso

Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-13 Thread Greg KH
On Wed, Aug 12, 2020 at 10:06:29PM -0700, Guenter Roeck wrote: > On Wed, Aug 12, 2020 at 08:48:13AM -0700, Guenter Roeck wrote: > > Hi, > > > > crbug.com/1114800 reports a hard lockup due to circular locking in the > > 8250 console driver. This is seen if CONFIG_PROVE_LOCKING is enabled. > > > >

Re: Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-12 Thread Guenter Roeck
On Wed, Aug 12, 2020 at 08:48:13AM -0700, Guenter Roeck wrote: > Hi, > > crbug.com/1114800 reports a hard lockup due to circular locking in the > 8250 console driver. This is seen if CONFIG_PROVE_LOCKING is enabled. > > Problem is as follows: > - serial8250_do_startup() locks the serial (console)

Recursive/circular locking in serial8250_console_write/serial8250_do_startup

2020-08-12 Thread Guenter Roeck
Hi, crbug.com/1114800 reports a hard lockup due to circular locking in the 8250 console driver. This is seen if CONFIG_PROVE_LOCKING is enabled. Problem is as follows: - serial8250_do_startup() locks the serial (console) port. - serial8250_do_startup() then disables interrupts if interrupts are