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@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 | 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);
--
2.32.0
