Re: kern/57833: kernel panic on xorg exit

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

The following reply was made to PR kern/57833; it has been noted by GNATS.

From: Taylor R Campbell <riastradh%NetBSD.org@localhost>
To: Ramiro Aceves <ea1abz%gmail.com@localhost>,
	"David H. Gutteridge" <david%gutteridge.ca@localhost>
Cc: gnats-bugs%NetBSD.org@localhost, netbsd-bugs%NetBSD.org@localhost
Subject: Re: kern/57833: kernel panic on xorg exit
Date: Thu, 11 Jan 2024 04:37:03 +0000

 This is a multi-part message in MIME format.
 --=_rcF9s9y1wcdKoxr8Pe72O3MsTry8XuO4
 
 Can you also try the attached patch, instead of the other one, to see
 what happens?
 
 (This might break things more spectacularly -- I haven't thought about
 whether it makes a lot of sense -- but it should at least prevent the
 particular crash you observed, if we ever get that far with it.)
 
 --=_rcF9s9y1wcdKoxr8Pe72O3MsTry8XuO4
 Content-Type: text/plain; charset="ISO-8859-1"; name="pr57833-i915gempages"
 Content-Transfer-Encoding: quoted-printable
 Content-Disposition: attachment; filename="pr57833-i915gempages.patch"
 
 diff --git a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c b/sys/=
 external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c
 index 8e592f008ef7..276ebbdbc234 100644
 --- a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c
 +++ b/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_mman.c
 @@ -677,6 +677,8 @@ void i915_gem_object_release_mmap_offset(struct drm_i91=
 5_gem_object *obj)
  		return;
  	for (i =3D 0; i < obj->base.size >> PAGE_SHIFT; i++) {
  		page =3D obj->mm.pages->sgl->sg_pgs[i];
 +		if (page =3D=3D NULL)
 +			continue;
  		vm_page =3D &page->p_vmp;
  		pmap_page_protect(vm_page, VM_PROT_NONE);
  	}
 diff --git a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_phys.c b/sys/=
 external/bsd/drm2/dist/drm/i915/gem/i915_gem_phys.c
 index 3f68276eea5f..29772bdbd8d9 100644
 --- a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_phys.c
 +++ b/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_phys.c
 @@ -83,8 +83,14 @@ static int i915_gem_object_get_pages_phys(struct drm_i91=
 5_gem_object *obj)
  	if (!st)
  		goto err_pci;
 =20
 +#ifdef __NetBSD__
 +	if (sg_alloc_table_from_bus_dmamem(st, dmat, &obj->mm.u.phys.seg, 1,
 +		GFP_KERNEL))
 +		goto err_st;
 +#else
  	if (sg_alloc_table(st, 1, GFP_KERNEL))
  		goto err_st;
 +#endif
 =20
  	sg =3D st->sgl;
  #ifdef __NetBSD__
 diff --git a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_region.c b/sy=
 s/external/bsd/drm2/dist/drm/i915/gem/i915_gem_region.c
 index 1a928988bd5f..5e8232b9634f 100644
 --- a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_region.c
 +++ b/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_region.c
 @@ -85,7 +85,15 @@ i915_gem_object_get_pages_buddy(struct drm_i915_gem_obje=
 ct *obj)
 =20
  		segs[i].ds_addr =3D mem->region.start + offset;
  		segs[i].ds_len =3D block_size;
 +		i++;
  	}
 +	KASSERT(i =3D=3D nsegs);
 +
 +	/* XXX errno NetBSD->Linux */
 +	ret =3D -bus_dmamem_export_pages(dmat, segs, nsegs, sg->sg_pgs,
 +	    sg->sg_npgs);
 +	if (ret)
 +		goto err;
 =20
  	/* XXX errno NetBSD->Linux */
  	ret =3D -bus_dmamap_create(dmat, size, nsegs, size, 0, BUS_DMA_WAITOK,
 diff --git a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_stolen.c b/sy=
 s/external/bsd/drm2/dist/drm/i915/gem/i915_gem_stolen.c
 index b53d543fa894..08cf7f0001bf 100644
 --- a/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_stolen.c
 +++ b/sys/external/bsd/drm2/dist/drm/i915/gem/i915_gem_stolen.c
 @@ -506,14 +506,13 @@ i915_pages_create_for_stolen(struct drm_device *dev,
  {
  	struct drm_i915_private *i915 =3D to_i915(dev);
  	struct sg_table *st;
 +	struct scatterlist *sg;
  #ifdef __NetBSD__
  	bus_dma_tag_t dmat =3D i915->drm.dmat;
  	bus_dma_segment_t *seg =3D NULL;
  	int nseg =3D 0, i;
  	bool loaded =3D false;
  	int ret;
 -#else
 -	struct scatterlist *sg;
  #endif
 =20
  	GEM_BUG_ON(range_overflows(offset, size, resource_size(&i915->dsm)));
 @@ -532,6 +531,7 @@ i915_pages_create_for_stolen(struct drm_device *dev,
  		return ERR_PTR(-ENOMEM);
  	}
 =20
 +	sg =3D st->sgl;
  #ifdef __NetBSD__
  	KASSERT((size % PAGE_SIZE) =3D=3D 0);
  	nseg =3D size / PAGE_SIZE;
 @@ -548,19 +548,25 @@ i915_pages_create_for_stolen(struct drm_device *dev,
  		seg[i].ds_len =3D PAGE_SIZE;
  	}
 =20
 +	/* XXX errno NetBSD->Linux */
 +	ret =3D -bus_dmamem_export_pages(dmat, seg, nseg, sg->sg_pgs,
 +	    sg->sg_npgs);
 +	if (ret)
 +		goto err;
 +
  	/* XXX errno NetBSD->Linux */
  	ret =3D -bus_dmamap_create(dmat, size, nseg, PAGE_SIZE, 0,
 -	    BUS_DMA_WAITOK, &st->sgl->sg_dmamap);
 +	    BUS_DMA_WAITOK, &sg->sg_dmamap);
  	if (ret) {
  		DRM_ERROR("failed to create DMA map for stolen object: %d\n",
  		    ret);
 -		st->sgl->sg_dmamap =3D NULL;
 +		sg->sg_dmamap =3D NULL;
  		goto out;
  	}
 -	st->sgl->sg_dmat =3D dmat;
 +	sg->sg_dmat =3D dmat;
 =20
  	/* XXX errno NetBSD->Liux */
 -	ret =3D -bus_dmamap_load_raw(dmat, st->sgl->sg_dmamap, seg, nseg, size,
 +	ret =3D -bus_dmamap_load_raw(dmat, sg->sg_dmamap, seg, nseg, size,
  	    BUS_DMA_WAITOK);
  	if (ret) {
  		DRM_ERROR("failed to load DMA map for stolen object: %d\n",
 @@ -571,13 +577,12 @@ i915_pages_create_for_stolen(struct drm_device *dev,
 =20
  out:	if (ret) {
  		if (loaded)
 -			bus_dmamap_unload(dmat, st->sgl->sg_dmamap);
 +			bus_dmamap_unload(dmat, sg->sg_dmamap);
  		sg_free_table(st);
  		kfree(st);
  		return ERR_PTR(ret);
  	}
  #else
 -	sg =3D st->sgl;
  	sg->offset =3D 0;
  	sg->length =3D size;
 =20
 
 --=_rcF9s9y1wcdKoxr8Pe72O3MsTry8XuO4--