linux-kernel - Re: [PATCH] drm/hisilicon: Fix rmmod hibmc

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Message-ID: <X9ilOeTwn9V0Jpdp@phenom.ffwll.local>
Date:   Tue, 15 Dec 2020 12:59:53 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Tian Tao <tiantao6@...ilicon.com>
Cc:     airlied@...ux.ie, daniel@...ll.ch, tzimmermann@...e.de,
        kraxel@...hat.com, alexander.deucher@....com, tglx@...utronix.de,
        dri-devel@...ts.freedesktop.org, xinliang.liu@...aro.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/hisilicon: Fix rmmod hibmc_drm failed

On Tue, Dec 15, 2020 at 11:01:39AM +0800, Tian Tao wrote:
> drm_irq_uninstall should be called before pci_disable_msi, if use
> devm_drm_irq_install to register the interrupt, the system will
> call pci_disable_msi first and then call drm_irq_uninstall, which
>  will result in the following callstack.
> 
> kernel BUG at drivers/pci/msi.c:376!
> Internal error: Oops - BUG: 0 [#1] SMP
> CPU: 93 PID: 173814 Comm: rmmod Tainted:
> pstate: a0400009 (NzCv daif +PAN -UAO -TCO BTYPE=--)
> pc : free_msi_irqs+0x17c/0x1a0
> lr : free_msi_irqs+0x16c/0x1a0
> sp : ffff2028157f7bd0
> x29: ffff2028157f7bd0 x28: ffff202849edab00
> x27: 0000000000000000 x26: 0000000000000000
> x25: 0000000000000000 x24: 0000000000000000
> x23: ffff0020851da000 x22: ffff0020851da2d8
> x21: ffff0020cc829000 x20: 0000000000000000
> x19: ffff0020d6714800 x18: 0000000000000010
> x17: 0000000000000000 x16: 0000000000000000
> x15: ffffffffffffffff x14: ffff2028957f77df
> x13: ffff2028157f77ed x12: 0000000000000000
> x11: 0000000000000040 x10: ffff800011b2f8e0
> x9 : ffff800011b2f8d8 x8 : ffff2020203fc458
> x7 : 0000000000000000 x6 : 0000000000000000
> x5 : ffff2020203fc430 x4 : ffff2020203fc4a0
> x3 : 0000000000000000 x2 : 0000000000000000
> x1 : 00000000000002c9 x0 : ffff0020d6719500
> Call trace:
>  free_msi_irqs+0x17c/0x1a0
>  pci_disable_msi+0xe4/0x118
>  hibmc_unload+0x44/0x80 [hibmc_drm]
>  hibmc_pci_remove+0x2c/0x38 [hibmc_drm]
>  pci_device_remove+0x48/0x108
>  device_release_driver_internal+0x118/0x1f0
>  driver_detach+0x6c/0xe0
>  bus_remove_driver+0x74/0x100
>  driver_unregister+0x34/0x60
>  pci_unregister_driver+0x24/0xd8
>  hibmc_pci_driver_exit+0x14/0xe768 [hibmc_drm]
>  __arm64_sys_delete_module+0x1fc/0x2d0
>  el0_svc_common.constprop.3+0xa8/0x188
>  do_el0_svc+0x80/0xa0
>  el0_sync_handler+0x8c/0xb0
>  el0_sync+0x15c/0x180
> Code: f940b400 b4ffff00 a903e7b8 f90013b5 (d4210000)
> ---[ end trace 310d94ee8abef44f ]---
> Kernel panic - not syncing: Oops - BUG: Fatal exception
> 

You should mention here which patch you're reverting. With that:

Acked-by: Daniel Vetter <daniel.vetter@...ll.ch>

Since the proper fix will probably take a while longer. Also why was this
not noticed when merging the original patch? hisilicon is the only user of
devm_drm_irq_install we have in-tree right now.
-Daniel

> Signed-off-by: Tian Tao <tiantao6@...ilicon.com>
> ---
>  drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> index e3ab765b..02f3bd1 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> +++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c
> @@ -251,6 +251,10 @@ static int hibmc_hw_init(struct hibmc_drm_private *priv)
>  static int hibmc_unload(struct drm_device *dev)
>  {
>  	drm_atomic_helper_shutdown(dev);
> +
> +	if (dev->irq_enabled)
> +		drm_irq_uninstall(dev);
> +
>  	pci_disable_msi(dev->pdev);
>  
>  	return 0;
> @@ -286,7 +290,7 @@ static int hibmc_load(struct drm_device *dev)
>  	if (ret) {
>  		drm_warn(dev, "enabling MSI failed: %d\n", ret);
>  	} else {
> -		ret = devm_drm_irq_install(dev, dev->pdev->irq);
> +		ret = drm_irq_install(dev, dev->pdev->irq);
>  		if (ret)
>  			drm_warn(dev, "install irq failed: %d\n", ret);
>  	}
> -- 
> 2.7.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch