On Thu, 27 May 2021 at 19:52, Matthew Auld <matthew.auld@xxxxxxxxx> wrote:
>
> This reverts commit b739f125e4ebd73d10ed30a856574e13649119ed.
>
> We are unfortunately seeing more issues like we did in 293837b9ac8d
> ("Revert "i915: fix remap_io_sg to verify the pgprot""), except this is
> now for the vm_fault_gtt path, where we are now hitting the same
> BUG_ON(!pte_none(*pte)):
>
> [10887.466150] kernel BUG at mm/memory.c:2183!
> [10887.466162] invalid opcode: 0000 [#1] PREEMPT SMP PTI
> [10887.466168] CPU: 0 PID: 7775 Comm: ffmpeg Tainted: G U 5.13.0-rc3-CI-Nightly #1
> [10887.466174] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./J4205-ITX, BIOS P1.40 07/14/2017
> [10887.466177] RIP: 0010:remap_pfn_range_notrack+0x30f/0x440
> [10887.466188] Code: e8 96 d7 e0 ff 84 c0 0f 84 27 01 00 00 48 ba 00 f0 ff ff ff ff 0f 00 4c 89 e0 48 c1 e0 0c 4d 85 ed 75 96 48 21 d0 31 f6 eb a9 <0f> 0b 48 39 37 0f 85 0e 01 00 00 48 8b 0c 24 48 39 4f 08 0f 85 00
> [10887.466193] RSP: 0018:ffffc90006e33c50 EFLAGS: 00010286
> [10887.466198] RAX: 800000000000002f RBX: 00007f5e01800000 RCX: 0000000000000028
> [10887.466201] RDX: 0000000000000001 RSI: ffffea0000000000 RDI: 0000000000000000
> [10887.466204] RBP: ffffea000033fea8 R08: 800000000000002f R09: ffff8881072256e0
> [10887.466207] R10: ffffc9000b84fff8 R11: 0000000017dab000 R12: 0000000000089f9f
> [10887.466210] R13: 800000000000002f R14: 00007f5e017e4000 R15: ffff88800cffaf20
> [10887.466213] FS: 00007f5e04849640(0000) GS:ffff888278000000(0000) knlGS:0000000000000000
> [10887.466216] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [10887.466220] CR2: 00007fd9b191a2ac CR3: 00000001829ac000 CR4: 00000000003506f0
> [10887.466223] Call Trace:
> [10887.466233] vm_fault_gtt+0x1ca/0x5d0 [i915]
> [10887.466381] ? ktime_get+0x38/0x90
> [10887.466389] __do_fault+0x37/0x90
> [10887.466395] __handle_mm_fault+0xc46/0x1200
> [10887.466402] handle_mm_fault+0xce/0x2a0
> [10887.466407] do_user_addr_fault+0x1c5/0x660
>
> Reverting this commit is reported to fix the issue.
>
> Reported-by: Eero Tamminen <eero.t.tamminen@xxxxxxxxx>
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/3519
> Fixes: b739f125e4eb ("i915: use io_mapping_map_user")
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Could someone give an ack for this? There are at least two separate
user reports for this issue.
> ---
> drivers/gpu/drm/i915/Kconfig | 1 -
> drivers/gpu/drm/i915/gem/i915_gem_mman.c | 9 ++---
> drivers/gpu/drm/i915/i915_drv.h | 3 ++
> drivers/gpu/drm/i915/i915_mm.c | 44 ++++++++++++++++++++++++
> 4 files changed, 52 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> index 93f4d059fc89..1e1cb245fca7 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -20,7 +20,6 @@ config DRM_I915
> select INPUT if ACPI
> select ACPI_VIDEO if ACPI
> select ACPI_BUTTON if ACPI
> - select IO_MAPPING
> select SYNC_FILE
> select IOSF_MBI
> select CRC32
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> index f6fe5cb01438..8598a1c78a4c 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> @@ -367,10 +367,11 @@ static vm_fault_t vm_fault_gtt(struct vm_fault *vmf)
> goto err_unpin;
>
> /* Finally, remap it using the new GTT offset */
> - ret = io_mapping_map_user(&ggtt->iomap, area, area->vm_start +
> - (vma->ggtt_view.partial.offset << PAGE_SHIFT),
> - (ggtt->gmadr.start + vma->node.start) >> PAGE_SHIFT,
> - min_t(u64, vma->size, area->vm_end - area->vm_start));
> + ret = remap_io_mapping(area,
> + area->vm_start + (vma->ggtt_view.partial.offset << PAGE_SHIFT),
> + (ggtt->gmadr.start + vma->node.start) >> PAGE_SHIFT,
> + min_t(u64, vma->size, area->vm_end - area->vm_start),
> + &ggtt->iomap);
> if (ret)
> goto err_fence;
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 0f6d27da69ac..e926f20c5b82 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1941,6 +1941,9 @@ int i915_reg_read_ioctl(struct drm_device *dev, void *data,
> struct drm_file *file);
>
> /* i915_mm.c */
> +int remap_io_mapping(struct vm_area_struct *vma,
> + unsigned long addr, unsigned long pfn, unsigned long size,
> + struct io_mapping *iomap);
> int remap_io_sg(struct vm_area_struct *vma,
> unsigned long addr, unsigned long size,
> struct scatterlist *sgl, resource_size_t iobase);
> diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c
> index 9a777b0ff59b..666808cb3a32 100644
> --- a/drivers/gpu/drm/i915/i915_mm.c
> +++ b/drivers/gpu/drm/i915/i915_mm.c
> @@ -37,6 +37,17 @@ struct remap_pfn {
> resource_size_t iobase;
> };
>
> +static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
> +{
> + struct remap_pfn *r = data;
> +
> + /* Special PTE are not associated with any struct page */
> + set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot)));
> + r->pfn++;
> +
> + return 0;
> +}
> +
> #define use_dma(io) ((io) != -1)
>
> static inline unsigned long sgt_pfn(const struct remap_pfn *r)
> @@ -66,7 +77,40 @@ static int remap_sg(pte_t *pte, unsigned long addr, void *data)
> return 0;
> }
>
> +/**
> + * remap_io_mapping - remap an IO mapping to userspace
> + * @vma: user vma to map to
> + * @addr: target user address to start at
> + * @pfn: physical address of kernel memory
> + * @size: size of map area
> + * @iomap: the source io_mapping
> + *
> + * Note: this is only safe if the mm semaphore is held when called.
> + */
> +int remap_io_mapping(struct vm_area_struct *vma,
> + unsigned long addr, unsigned long pfn, unsigned long size,
> + struct io_mapping *iomap)
> +{
> + struct remap_pfn r;
> + int err;
> +
> #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)
> + GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
> +
> + /* We rely on prevalidation of the io-mapping to skip track_pfn(). */
> + r.mm = vma->vm_mm;
> + r.pfn = pfn;
> + r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
> + (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK));
> +
> + err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r);
> + if (unlikely(err)) {
> + zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT);
> + return err;
> + }
> +
> + return 0;
> +}
>
> /**
> * remap_io_sg - remap an IO mapping to userspace
> --
> 2.26.3
>
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