From 8d51e0fd3e698919d2adeff71936377f0c0d4aa0 Mon Sep 17 00:00:00 2001 From: Lizhi Hou Date: Thu, 23 Jul 2026 00:42:56 -0700 Subject: [PATCH] accel/amxdna: Fix page-insertion errors in amdxdna_insert_pages() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Two error paths in amdxdna_insert_pages() called vma->vm_ops->close(vma) before returning an error code to the caller. This is incorrect: amdxdna_gem_obj_mmap() registers an HMM interval notifier before calling amdxdna_insert_pages(), and on a hard error it jumps to hmm_unreg to undo that registration. Calling vm_ops->close() manually — which drops the shmem pages_pin_count and the GEM object reference that backs the VMA — before the mmap syscall has even returned causes those resources to be released while the VMA is still alive. The kernel VMA teardown will call vm_ops->close() a second time when the process later unmaps the range, producing a reference count underflow. Replace both hard-error returns with a deferred-fault approach that keeps the VMA alive and retries page insertion through the HMM range-fault path. Fixes: e486147c912f ("accel/amdxdna: Add BO import and export") Reviewed-by: Max Zhen Signed-off-by: Lizhi Hou Link: https://patch.msgid.link/20260723074256.2435143-1-lizhi.hou@amd.com --- drivers/accel/amdxdna/amdxdna_gem.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/drivers/accel/amdxdna/amdxdna_gem.c b/drivers/accel/amdxdna/amdxdna_gem.c index 4628a2787265..aec69d5f463e 100644 --- a/drivers/accel/amdxdna/amdxdna_gem.c +++ b/drivers/accel/amdxdna/amdxdna_gem.c @@ -436,6 +436,23 @@ static void amdxdna_gem_dev_obj_free(struct drm_gem_object *gobj) amdxdna_gem_destroy_obj(abo); } +static void amdxdna_mark_mapp_invalid(struct amdxdna_gem_obj *abo, + struct vm_area_struct *vma) +{ + struct amdxdna_dev *xdna = to_xdna_dev(to_gobj(abo)->dev); + struct amdxdna_umap *mapp; + + down_write(&xdna->notifier_lock); + abo->mem.map_invalid = true; + list_for_each_entry(mapp, &abo->mem.umap_list, node) { + if (compare_range(mapp, vma->vm_mm, vma->vm_start, vma->vm_end)) { + mapp->invalid = true; + break; + } + } + up_write(&xdna->notifier_lock); +} + static int amdxdna_insert_pages(struct amdxdna_gem_obj *abo, struct vm_area_struct *vma) { @@ -457,8 +474,7 @@ static int amdxdna_insert_pages(struct amdxdna_gem_obj *abo, &num_pages); if (ret) { XDNA_ERR(xdna, "Failed insert pages %d", ret); - vma->vm_ops->close(vma); - return ret; + amdxdna_mark_mapp_invalid(abo, vma); } return 0; @@ -478,9 +494,9 @@ static int amdxdna_insert_pages(struct amdxdna_gem_obj *abo, fault_ret = handle_mm_fault(vma, vma->vm_start + offset, FAULT_FLAG_WRITE, NULL); if (fault_ret & VM_FAULT_ERROR) { - vma->vm_ops->close(vma); XDNA_ERR(xdna, "Fault in page failed"); - return -EFAULT; + amdxdna_mark_mapp_invalid(abo, vma); + break; } offset += PAGE_SIZE;