From: Chen-Yu Tsai Date: Tue, 17 Mar 2026 04:00:32 +0000 (+0800) Subject: drm/gem-dma: set VM_DONTDUMP for mmap X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e3eb0e70815cc02ea15298818e37d8b0a0930ab1;p=thirdparty%2Fkernel%2Fstable.git drm/gem-dma: set VM_DONTDUMP for mmap When the mmap function was converted from a file op to a GEM object function in commit f5ca8eb6f9bd ("drm/cma-helper: Implement mmap as GEM CMA object functions") some VM flags were not lifted from drm_gem_mmap(): - VM_IO - VM_DONTEXPAND - VM_DONTDUMP VM_DONTEXPAND was added back in commit 59f39bfa6553 ("drm/cma-helper: Set VM_DONTEXPAND for mmap"). VM_IO doesn't make sense since these are memory buffers, while "IO tells people not to look at these pages (accesses can have side effects)". Add back VM_DONTDUMP. This matches the behavior of most other GEM implementations. Reviewed-by: Thomas Zimmermann Link: https://patch.msgid.link/20260317040034.617585-1-wenst@chromium.org Signed-off-by: Chen-Yu Tsai --- diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c b/drivers/gpu/drm/drm_gem_dma_helper.c index 70f83e464476..1c00a71ab3c9 100644 --- a/drivers/gpu/drm/drm_gem_dma_helper.c +++ b/drivers/gpu/drm/drm_gem_dma_helper.c @@ -537,7 +537,7 @@ int drm_gem_dma_mmap(struct drm_gem_dma_object *dma_obj, struct vm_area_struct * * the whole buffer. */ vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node); - vm_flags_mod(vma, VM_DONTEXPAND, VM_PFNMAP); + vm_flags_mod(vma, VM_DONTDUMP | VM_DONTEXPAND, VM_PFNMAP); if (dma_obj->map_noncoherent) { vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);