Re: [PATCH] drm/hisilicon: Fix rmmod hibmc_drm failed

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Dec 15, 2020 at 12:59:53PM +0100, Daniel Vetter wrote:
> 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@ffwll.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.

I also just noticed that you didn't add devm_drm_irq_install to the list
of functions in Documentation/driver-api/driver-model/devres.rst. Can you
please submit a patch to fix this?

Thanks, Daniel

> -Daniel
> 
> > Signed-off-by: Tian Tao <tiantao6@hisilicon.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

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