2023-09-19 15:08:29

by H. Nikolaus Schaller

[permalink] [raw]
Subject: [PATCH] omap: dsi: do not WARN on detach if dsidev was never attached

dsi_init_output() called by dsi_probe() may fail. In that
case mipi_dsi_host_unregister() is called which may call
omap_dsi_host_detach() with uninitialized dsi->dsidev
because omap_dsi_host_attach() was never called before.

This happens if the panel driver asks for an EPROBE_DEFER.

So let's suppress the WARN() in this special case.

[ 7.416759] WARNING: CPU: 0 PID: 32 at drivers/gpu/drm/omapdrm/dss/dsi.c:4419 omap_dsi_host_detach+0x3c/0xbc [omapdrm]
[ 7.436053] Modules linked in: ina2xx_adc snd_soc_ts3a227e bq2429x_charger bq27xxx_battery_i2c(+) bq27xxx_battery ina2xx tca8418_keypad as5013(+) omapdrm hci_uart cec palmas_pwrbutton btbcm bmp280_spi palmas_gpadc bluetooth usb3503 ecdh_generic bmc150_accel_i2c bmg160_i2c ecc bmc150_accel_core bmg160_core bmc150_magn_i2c bmp280_i2c bmc150_magn bno055 industrialio_triggered_buffer bmp280 kfifo_buf snd_soc_omap_aess display_connector drm_kms_helper syscopyarea snd_soc_omap_mcbsp snd_soc_ti_sdma sysfillrect ti_tpd12s015 sysimgblt fb_sys_fops wwan_on_off snd_soc_gtm601 generic_adc_battery drm snd_soc_w2cbw003_bt industrialio drm_panel_orientation_quirks pwm_bl pwm_omap_dmtimer ip_tables x_tables ipv6 autofs4
[ 7.507068] CPU: 0 PID: 32 Comm: kworker/u4:2 Tainted: G W 6.1.0-rc3-letux-lpae+ #11107
[ 7.516964] Hardware name: Generic OMAP5 (Flattened Device Tree)
[ 7.523284] Workqueue: events_unbound deferred_probe_work_func
[ 7.529456] unwind_backtrace from show_stack+0x10/0x14
[ 7.534972] show_stack from dump_stack_lvl+0x40/0x4c
[ 7.540315] dump_stack_lvl from __warn+0xb0/0x164
[ 7.545379] __warn from warn_slowpath_fmt+0x70/0x9c
[ 7.550625] warn_slowpath_fmt from omap_dsi_host_detach+0x3c/0xbc [omapdrm]
[ 7.558137] omap_dsi_host_detach [omapdrm] from mipi_dsi_remove_device_fn+0x10/0x20
[ 7.566376] mipi_dsi_remove_device_fn from device_for_each_child+0x60/0x94
[ 7.573729] device_for_each_child from mipi_dsi_host_unregister+0x20/0x54
[ 7.580992] mipi_dsi_host_unregister from dsi_probe+0x5d8/0x744 [omapdrm]
[ 7.588315] dsi_probe [omapdrm] from platform_probe+0x58/0xa8
[ 7.594542] platform_probe from really_probe+0x144/0x2ac
[ 7.600249] really_probe from __driver_probe_device+0xc4/0xd8
[ 7.606411] __driver_probe_device from driver_probe_device+0x3c/0xb8
[ 7.613216] driver_probe_device from __device_attach_driver+0x58/0xbc
[ 7.620115] __device_attach_driver from bus_for_each_drv+0xa0/0xb4
[ 7.626737] bus_for_each_drv from __device_attach+0xdc/0x150
[ 7.632808] __device_attach from bus_probe_device+0x28/0x80
[ 7.638792] bus_probe_device from deferred_probe_work_func+0x84/0xa0
[ 7.645595] deferred_probe_work_func from process_one_work+0x1a4/0x2d8
[ 7.652587] process_one_work from worker_thread+0x214/0x2b8
[ 7.658567] worker_thread from kthread+0xe4/0xf0
[ 7.663542] kthread from ret_from_fork+0x14/0x1c
[ 7.668515] Exception stack(0xf01b5fb0 to 0xf01b5ff8)
[ 7.673827] 5fa0: 00000000 00000000 00000000 00000000
[ 7.682435] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 7.691038] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000

Signed-off-by: H. Nikolaus Schaller <[email protected]>
---
drivers/gpu/drm/omapdrm/dss/dsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
index ea63c64d3a1ab..c37eb6b1b9a39 100644
--- a/drivers/gpu/drm/omapdrm/dss/dsi.c
+++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
@@ -4411,7 +4411,7 @@ static int omap_dsi_host_detach(struct mipi_dsi_host *host,
{
struct dsi_data *dsi = host_to_omap(host);

- if (WARN_ON(dsi->dsidev != client))
+ if (!dsi->dsidev || WARN_ON(dsi->dsidev != client))
return -EINVAL;

cancel_delayed_work_sync(&dsi->dsi_disable_work);
--
2.42.0


2023-09-20 05:57:00

by Tony Lindgren

[permalink] [raw]
Subject: Re: [PATCH] omap: dsi: do not WARN on detach if dsidev was never attached

* H. Nikolaus Schaller <[email protected]> [230919 13:38]:
> dsi_init_output() called by dsi_probe() may fail. In that
> case mipi_dsi_host_unregister() is called which may call
> omap_dsi_host_detach() with uninitialized dsi->dsidev
> because omap_dsi_host_attach() was never called before.
>
> This happens if the panel driver asks for an EPROBE_DEFER.
>
> So let's suppress the WARN() in this special case.

Reviewed-by: Tony Lindgren <[email protected]>

Thanks,

Tony

2023-09-20 22:02:00

by Sebastian Reichel

[permalink] [raw]
Subject: Re: [PATCH] omap: dsi: do not WARN on detach if dsidev was never attached

Hi,

On Tue, Sep 19, 2023 at 03:37:28PM +0200, H. Nikolaus Schaller wrote:
> dsi_init_output() called by dsi_probe() may fail. In that
> case mipi_dsi_host_unregister() is called which may call
> omap_dsi_host_detach() with uninitialized dsi->dsidev
> because omap_dsi_host_attach() was never called before.
>
> This happens if the panel driver asks for an EPROBE_DEFER.
>
> So let's suppress the WARN() in this special case.

...

> Signed-off-by: H. Nikolaus Schaller <[email protected]>
> ---

Reviewed-by: Sebastian Reichel <[email protected]>

-- Sebastian

> drivers/gpu/drm/omapdrm/dss/dsi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> index ea63c64d3a1ab..c37eb6b1b9a39 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -4411,7 +4411,7 @@ static int omap_dsi_host_detach(struct mipi_dsi_host *host,
> {
> struct dsi_data *dsi = host_to_omap(host);
>
> - if (WARN_ON(dsi->dsidev != client))
> + if (!dsi->dsidev || WARN_ON(dsi->dsidev != client))
> return -EINVAL;
>
> cancel_delayed_work_sync(&dsi->dsi_disable_work);
> --
> 2.42.0
>


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2023-09-21 18:34:23

by Tony Lindgren

[permalink] [raw]
Subject: Re: [PATCH] omap: dsi: do not WARN on detach if dsidev was never attached

* Tomi Valkeinen <[email protected]> [230921 10:53]:
> I sent a patch to the DSI framework code,
> "[PATCH] drm/mipi-dsi: Fix detach call without attach".
>
> If that fixes the issue (please test, I don't have a suitable platform),
> perhaps it's a better fix as detach really shouldn't be called if attach has
> not been called.

Yup that works for me, replied with my Tested-by on that thread.

Thanks,

Tony

2023-09-22 00:50:57

by Tomi Valkeinen

[permalink] [raw]
Subject: Re: [PATCH] omap: dsi: do not WARN on detach if dsidev was never attached

Hi,

On 19/09/2023 16:37, H. Nikolaus Schaller wrote:
> dsi_init_output() called by dsi_probe() may fail. In that
> case mipi_dsi_host_unregister() is called which may call
> omap_dsi_host_detach() with uninitialized dsi->dsidev
> because omap_dsi_host_attach() was never called before.
>
> This happens if the panel driver asks for an EPROBE_DEFER.
>
> So let's suppress the WARN() in this special case.
>
> [ 7.416759] WARNING: CPU: 0 PID: 32 at drivers/gpu/drm/omapdrm/dss/dsi.c:4419 omap_dsi_host_detach+0x3c/0xbc [omapdrm]
> [ 7.436053] Modules linked in: ina2xx_adc snd_soc_ts3a227e bq2429x_charger bq27xxx_battery_i2c(+) bq27xxx_battery ina2xx tca8418_keypad as5013(+) omapdrm hci_uart cec palmas_pwrbutton btbcm bmp280_spi palmas_gpadc bluetooth usb3503 ecdh_generic bmc150_accel_i2c bmg160_i2c ecc bmc150_accel_core bmg160_core bmc150_magn_i2c bmp280_i2c bmc150_magn bno055 industrialio_triggered_buffer bmp280 kfifo_buf snd_soc_omap_aess display_connector drm_kms_helper syscopyarea snd_soc_omap_mcbsp snd_soc_ti_sdma sysfillrect ti_tpd12s015 sysimgblt fb_sys_fops wwan_on_off snd_soc_gtm601 generic_adc_battery drm snd_soc_w2cbw003_bt industrialio drm_panel_orientation_quirks pwm_bl pwm_omap_dmtimer ip_tables x_tables ipv6 autofs4
> [ 7.507068] CPU: 0 PID: 32 Comm: kworker/u4:2 Tainted: G W 6.1.0-rc3-letux-lpae+ #11107
> [ 7.516964] Hardware name: Generic OMAP5 (Flattened Device Tree)
> [ 7.523284] Workqueue: events_unbound deferred_probe_work_func
> [ 7.529456] unwind_backtrace from show_stack+0x10/0x14
> [ 7.534972] show_stack from dump_stack_lvl+0x40/0x4c
> [ 7.540315] dump_stack_lvl from __warn+0xb0/0x164
> [ 7.545379] __warn from warn_slowpath_fmt+0x70/0x9c
> [ 7.550625] warn_slowpath_fmt from omap_dsi_host_detach+0x3c/0xbc [omapdrm]
> [ 7.558137] omap_dsi_host_detach [omapdrm] from mipi_dsi_remove_device_fn+0x10/0x20
> [ 7.566376] mipi_dsi_remove_device_fn from device_for_each_child+0x60/0x94
> [ 7.573729] device_for_each_child from mipi_dsi_host_unregister+0x20/0x54
> [ 7.580992] mipi_dsi_host_unregister from dsi_probe+0x5d8/0x744 [omapdrm]
> [ 7.588315] dsi_probe [omapdrm] from platform_probe+0x58/0xa8
> [ 7.594542] platform_probe from really_probe+0x144/0x2ac
> [ 7.600249] really_probe from __driver_probe_device+0xc4/0xd8
> [ 7.606411] __driver_probe_device from driver_probe_device+0x3c/0xb8
> [ 7.613216] driver_probe_device from __device_attach_driver+0x58/0xbc
> [ 7.620115] __device_attach_driver from bus_for_each_drv+0xa0/0xb4
> [ 7.626737] bus_for_each_drv from __device_attach+0xdc/0x150
> [ 7.632808] __device_attach from bus_probe_device+0x28/0x80
> [ 7.638792] bus_probe_device from deferred_probe_work_func+0x84/0xa0
> [ 7.645595] deferred_probe_work_func from process_one_work+0x1a4/0x2d8
> [ 7.652587] process_one_work from worker_thread+0x214/0x2b8
> [ 7.658567] worker_thread from kthread+0xe4/0xf0
> [ 7.663542] kthread from ret_from_fork+0x14/0x1c
> [ 7.668515] Exception stack(0xf01b5fb0 to 0xf01b5ff8)
> [ 7.673827] 5fa0: 00000000 00000000 00000000 00000000
> [ 7.682435] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> [ 7.691038] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
>
> Signed-off-by: H. Nikolaus Schaller <[email protected]>
> ---
> drivers/gpu/drm/omapdrm/dss/dsi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> index ea63c64d3a1ab..c37eb6b1b9a39 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -4411,7 +4411,7 @@ static int omap_dsi_host_detach(struct mipi_dsi_host *host,
> {
> struct dsi_data *dsi = host_to_omap(host);
>
> - if (WARN_ON(dsi->dsidev != client))
> + if (!dsi->dsidev || WARN_ON(dsi->dsidev != client))
> return -EINVAL;
>
> cancel_delayed_work_sync(&dsi->dsi_disable_work);

I sent a patch to the DSI framework code,
"[PATCH] drm/mipi-dsi: Fix detach call without attach".

If that fixes the issue (please test, I don't have a suitable platform),
perhaps it's a better fix as detach really shouldn't be called if attach
has not been called.

Tomi