On Fri, Jul 9, 2021 at 1:47 PM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
>
> Commit 375cca1cfeb5 ("drm/vgem: Implement mmap as GEM object function")
> accidentally removed the actual mmap functionality from vgem. Restore
> the original implementation and VMA flags.
Ah yes that explains things.
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>
> Fixes access to unmapped memory:
>
> [ 106.591744] BUG: KASAN: vmalloc-out-of-bounds in do_fault+0x38/0x480
> [ 106.598154] Read of size 8 at addr ffffffffc10c44a8 by task vgem_basic/1514
> [ 106.605173]
> [ 106.606678] CPU: 1 PID: 1514 Comm: vgem_basic Tainted: G E 5.13.0-1-default+ #990
> [ 106.615535] Hardware name: Dell Inc. OptiPlex 9020/0N4YC8, BIOS A24 10/24/2018
> [ 106.622818] Call Trace:
> [ 106.625289] dump_stack+0xa5/0xdc
> [ 106.628642] print_address_description.constprop.0+0x18/0x100
> [ 106.634439] ? do_fault+0x38/0x480
> [ 106.637872] kasan_report.cold+0x7c/0xd8
> [ 106.641834] ? do_fault+0x38/0x480
> [ 106.645274] do_fault+0x38/0x480
> [ 106.648535] __handle_mm_fault+0x935/0xb00
> [ 106.652676] ? vm_iomap_memory+0xe0/0xe0
> [ 106.656634] ? __lock_release+0x12f/0x4e0
> [ 106.660696] ? count_memcg_event_mm.part.0+0xb9/0x190
> [ 106.665799] handle_mm_fault+0xd0/0x370
> [ 106.669675] do_user_addr_fault+0x2a0/0x8c0
> [ 106.673908] exc_page_fault+0x64/0xf0
> [ 106.677604] ? asm_exc_page_fault+0x8/0x30
> [ 106.681739] asm_exc_page_fault+0x1e/0x30
> [ 106.685782] RIP: 0033:0x402e12
> ...
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Fixes: 375cca1cfeb5 ("drm/vgem: Implement mmap as GEM object function")
> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Cc: Christian König <christian.koenig@xxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: "Christian König" <christian.koenig@xxxxxxx>
> Cc: Melissa Wen <melissa.srw@xxxxxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> Cc: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> Cc: Lee Jones <lee.jones@xxxxxxxxxx>
> ---
> drivers/gpu/drm/vgem/vgem_drv.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
> index df634aa52638..f50fd10c4fad 100644
> --- a/drivers/gpu/drm/vgem/vgem_drv.c
> +++ b/drivers/gpu/drm/vgem/vgem_drv.c
> @@ -364,8 +364,17 @@ static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *ma
>
> static int vgem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> {
> + int ret;
> +
> + if (!obj->filp)
> + return -ENODEV;
> +
> + ret = call_mmap(obj->filp, vma);
> + if (ret)
> + return ret;
> +
> vma_set_file(vma, obj->filp);
> - vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
> + vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
> vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
>
> --
> 2.32.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
