Commit 375cca1cfeb5 ("drm/vgem: Implement mmap as GEM object function") accidentally removed the actual mmap functionality from vgem. Restore the original implementation by restoring the vm_pgoff in the mmap code.
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 ...
v2: * restore vma.vm_pgoff instead of mapping the pages
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Fixes: 375cca1cfeb5 ("drm/vgem: Implement mmap as GEM object function") Cc: Thomas Zimmermann tzimmermann@suse.de Cc: Christian König christian.koenig@amd.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: "Christian König" christian.koenig@amd.com Cc: Melissa Wen melissa.srw@gmail.com Cc: Jason Gunthorpe jgg@ziepe.ca Cc: Gerd Hoffmann kraxel@redhat.com Cc: Lee Jones lee.jones@linaro.org --- drivers/gpu/drm/vgem/vgem_drv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c index df634aa52638..e92d1f2e02c4 100644 --- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -364,8 +364,8 @@ 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) { - vma_set_file(vma, obj->filp); - vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; + vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node); + 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);