patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus

patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    serial: sh-sci: Initialize spinlock for uart console

to my tty git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From f38278e9b810b06aff2981d505267be984423ba3 Mon Sep 17 00:00:00 2001
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Date: Wed, 1 Jul 2020 16:41:40 +0100
Subject: serial: sh-sci: Initialize spinlock for uart console

serial core expects the spinlock to be initialized by the controller
driver for serial console, this patch makes sure the spinlock is
initialized, fixing the below issue:

[    0.865928] BUG: spinlock bad magic on CPU#0, swapper/0/1
[    0.865945]  lock: sci_ports+0x0/0x4c80, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[    0.865955] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc1+ #112
[    0.865961] Hardware name: HopeRun HiHope RZ/G2H with sub board (DT)
[    0.865968] Call trace:
[    0.865979]  dump_backtrace+0x0/0x1d8
[    0.865985]  show_stack+0x14/0x20
[    0.865996]  dump_stack+0xe8/0x130
[    0.866006]  spin_dump+0x6c/0x88
[    0.866012]  do_raw_spin_lock+0xb0/0xf8
[    0.866023]  _raw_spin_lock_irqsave+0x80/0xa0
[    0.866032]  uart_add_one_port+0x3a4/0x4e0
[    0.866039]  sci_probe+0x504/0x7c8
[    0.866048]  platform_drv_probe+0x50/0xa0
[    0.866059]  really_probe+0xdc/0x330
[    0.866066]  driver_probe_device+0x58/0xb8
[    0.866072]  device_driver_attach+0x6c/0x90
[    0.866078]  __driver_attach+0x88/0xd0
[    0.866085]  bus_for_each_dev+0x74/0xc8
[    0.866091]  driver_attach+0x20/0x28
[    0.866098]  bus_add_driver+0x14c/0x1f8
[    0.866104]  driver_register+0x60/0x110
[    0.866109]  __platform_driver_register+0x40/0x48
[    0.866119]  sci_init+0x2c/0x34
[    0.866127]  do_one_initcall+0x88/0x428
[    0.866137]  kernel_init_freeable+0x2c0/0x328
[    0.866143]  kernel_init+0x10/0x108
[    0.866150]  ret_from_fork+0x10/0x18

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1593618100-2151-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/sh-sci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index e1179e74a2b8..204bb68ce3ca 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -3301,6 +3301,9 @@ static int sci_probe_single(struct platform_device *dev,
 		sciport->port.flags |= UPF_HARD_FLOW;
 	}
 
+	if (sci_uart_driver.cons->index == sciport->port.line)
+		spin_lock_init(&sciport->port.lock);
+
 	ret = uart_add_one_port(&sci_uart_driver, &sciport->port);
 	if (ret) {
 		sci_cleanup_single(sciport);
-- 
2.27.0

RE: patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus

[Prabhakar Mahadev Lad]

Hi Greg,

> -----Original Message-----
> From: gregkh@linuxfoundation.org <gregkh@linuxfoundation.org>
> Sent: 03 July 2020 09:41
> To: Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>; Biju Das <biju.das.jz@bp.renesas.com>;
> gregkh@linuxfoundation.org; stable@vger.kernel.org
> Subject: patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus
>
>
> This is a note to let you know that I've just added the patch titled
>
>     serial: sh-sci: Initialize spinlock for uart console
>
> to my tty git tree which can be found at
>     git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
> in the tty-linus branch.
>
> The patch will show up in the next release of the linux-next tree
> (usually sometime within the next 24 hours during the week.)
>
> The patch will hopefully also be merged in Linus's tree for the
> next -rc kernel release.
>
> If you have any questions about this process, please let me know.
>
It looks like it's a regression in serial_core.c [1] as Geert pointed out [2]. Please drop this patch until we come to a conclusion.

[1] https://www.spinics.net/lists/linux-serial/msg37119.html
[2] https://patchwork.kernel.org/patch/11636731/

Cheers,
--Prabhakar
>
> From f38278e9b810b06aff2981d505267be984423ba3 Mon Sep 17 00:00:00 2001
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Date: Wed, 1 Jul 2020 16:41:40 +0100
> Subject: serial: sh-sci: Initialize spinlock for uart console
>
> serial core expects the spinlock to be initialized by the controller
> driver for serial console, this patch makes sure the spinlock is
> initialized, fixing the below issue:
>
> [    0.865928] BUG: spinlock bad magic on CPU#0, swapper/0/1
> [    0.865945]  lock: sci_ports+0x0/0x4c80, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
> [    0.865955] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc1+ #112
> [    0.865961] Hardware name: HopeRun HiHope RZ/G2H with sub board (DT)
> [    0.865968] Call trace:
> [    0.865979]  dump_backtrace+0x0/0x1d8
> [    0.865985]  show_stack+0x14/0x20
> [    0.865996]  dump_stack+0xe8/0x130
> [    0.866006]  spin_dump+0x6c/0x88
> [    0.866012]  do_raw_spin_lock+0xb0/0xf8
> [    0.866023]  _raw_spin_lock_irqsave+0x80/0xa0
> [    0.866032]  uart_add_one_port+0x3a4/0x4e0
> [    0.866039]  sci_probe+0x504/0x7c8
> [    0.866048]  platform_drv_probe+0x50/0xa0
> [    0.866059]  really_probe+0xdc/0x330
> [    0.866066]  driver_probe_device+0x58/0xb8
> [    0.866072]  device_driver_attach+0x6c/0x90
> [    0.866078]  __driver_attach+0x88/0xd0
> [    0.866085]  bus_for_each_dev+0x74/0xc8
> [    0.866091]  driver_attach+0x20/0x28
> [    0.866098]  bus_add_driver+0x14c/0x1f8
> [    0.866104]  driver_register+0x60/0x110
> [    0.866109]  __platform_driver_register+0x40/0x48
> [    0.866119]  sci_init+0x2c/0x34
> [    0.866127]  do_one_initcall+0x88/0x428
> [    0.866137]  kernel_init_freeable+0x2c0/0x328
> [    0.866143]  kernel_init+0x10/0x108
> [    0.866150]  ret_from_fork+0x10/0x18
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console")
> Cc: stable <stable@vger.kernel.org>
> Link: https://lore.kernel.org/r/1593618100-2151-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  drivers/tty/serial/sh-sci.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
> index e1179e74a2b8..204bb68ce3ca 100644
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -3301,6 +3301,9 @@ static int sci_probe_single(struct platform_device *dev,
>  sciport->port.flags |= UPF_HARD_FLOW;
>  }
>
> +if (sci_uart_driver.cons->index == sciport->port.line)
> +spin_lock_init(&sciport->port.lock);
> +
>  ret = uart_add_one_port(&sci_uart_driver, &sciport->port);
>  if (ret) {
>  sci_cleanup_single(sciport);
> --
> 2.27.0
>



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Re: patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus

[gregkh]

On Fri, Jul 03, 2020 at 08:53:18AM +0000, Prabhakar Mahadev Lad wrote:
> Hi Greg,
> 
> > -----Original Message-----
> > From: gregkh@linuxfoundation.org <gregkh@linuxfoundation.org>
> > Sent: 03 July 2020 09:41
> > To: Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>; Biju Das <biju.das.jz@bp.renesas.com>;
> > gregkh@linuxfoundation.org; stable@vger.kernel.org
> > Subject: patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus
> >
> >
> > This is a note to let you know that I've just added the patch titled
> >
> >     serial: sh-sci: Initialize spinlock for uart console
> >
> > to my tty git tree which can be found at
> >     git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
> > in the tty-linus branch.
> >
> > The patch will show up in the next release of the linux-next tree
> > (usually sometime within the next 24 hours during the week.)
> >
> > The patch will hopefully also be merged in Linus's tree for the
> > next -rc kernel release.
> >
> > If you have any questions about this process, please let me know.
> >
> It looks like it's a regression in serial_core.c [1] as Geert pointed out [2]. Please drop this patch until we come to a conclusion.
> 
> [1] https://www.spinics.net/lists/linux-serial/msg37119.html
> [2] https://patchwork.kernel.org/patch/11636731/

We have had MANY patches for individual drivers to fix up the issue with
that serial_core patch.  I think, and hope, they are all now caught.  If
not, please let us know, but for now, this patch is needed, so I'll keep
it.

thanks,

greg k-h

Re: patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus

[Geert Uytterhoeven]

Hi Greg,

On Fri, Jul 3, 2020 at 10:58 AM gregkh@linuxfoundation.org
<gregkh@linuxfoundation.org> wrote:
> On Fri, Jul 03, 2020 at 08:53:18AM +0000, Prabhakar Mahadev Lad wrote:
> > > -----Original Message-----
> > > From: gregkh@linuxfoundation.org <gregkh@linuxfoundation.org>
> > > Sent: 03 July 2020 09:41
> > > To: Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>; Biju Das <biju.das.jz@bp.renesas.com>;
> > > gregkh@linuxfoundation.org; stable@vger.kernel.org
> > > Subject: patch "serial: sh-sci: Initialize spinlock for uart console" added to tty-linus
> > >
> > >
> > > This is a note to let you know that I've just added the patch titled
> > >
> > >     serial: sh-sci: Initialize spinlock for uart console
> > >
> > > to my tty git tree which can be found at
> > >     git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
> > > in the tty-linus branch.
> > >
> > > The patch will show up in the next release of the linux-next tree
> > > (usually sometime within the next 24 hours during the week.)
> > >
> > > The patch will hopefully also be merged in Linus's tree for the
> > > next -rc kernel release.
> > >
> > > If you have any questions about this process, please let me know.
> > >
> > It looks like it's a regression in serial_core.c [1] as Geert pointed out [2]. Please drop this patch until we come to a conclusion.
> >
> > [1] https://www.spinics.net/lists/linux-serial/msg37119.html
> > [2] https://patchwork.kernel.org/patch/11636731/
>
> We have had MANY patches for individual drivers to fix up the issue with
> that serial_core patch.  I think, and hope, they are all now caught.  If
> not, please let us know, but for now, this patch is needed, so I'll keep
> it.

Yeah, let's fix all the fixes when the core issue is fixed ;-)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds