If vma is not found, the application has freed the memory using madvise
MADV_FREE, but driver don't receive the unmap from CPU MMU notifier
callback, the memory is still mapped on GPUs. svm restore work will
schedule the work to retry forever. Then user queues not resumed and
cause application hangs to wait for queue finish.
svm restore work should unmap the memory range from GPUs then resume
queues. If GPU page fault happens on the unmapped address, it is
application use-after-free bug.
Signed-off-by: Philip Yang <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 75 ++++++++++++++--------------
1 file changed, 38 insertions(+), 37 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 0aadd20be56a..e87c9b3533b9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1708,50 +1708,51 @@ static int svm_range_validate_and_map(struct mm_struct
*mm,
bool readonly;
vma = vma_lookup(mm, addr);
- if (vma) {
- readonly = !(vma->vm_flags & VM_WRITE);
+ next = vma ? min(vma->vm_end, end) : end;
+ npages = (next - addr) >> PAGE_SHIFT;
- next = min(vma->vm_end, end);
- npages = (next - addr) >> PAGE_SHIFT;
+ if (!vma || !(vma->vm_flags & VM_READ)) {
/* HMM requires at least READ permissions. If provided
with PROT_NONE,
* unmap the memory. If it's not already mapped, this
is a no-op
* If PROT_WRITE is provided without READ, warn first
then unmap
+ * If vma is not found, addr is invalid, unmap from GPUs
*/
- if (!(vma->vm_flags & VM_READ)) {
- unsigned long e, s;
-
- svm_range_lock(prange);
- if (vma->vm_flags & VM_WRITE)
- pr_debug("VM_WRITE without VM_READ is not
supported");
- s = max(addr >> PAGE_SHIFT, prange->start);
- e = s + npages - 1;
- r = svm_range_unmap_from_gpus(prange, s, e,
-
KFD_SVM_UNMAP_TRIGGER_UNMAP_FROM_CPU);
- svm_range_unlock(prange);
- /* If unmap returns non-zero, we'll bail on the
next for loop
- * iteration, so just leave r and continue
- */
- addr = next;
- continue;
- }
+ unsigned long e, s;
+
+ svm_range_lock(prange);
+ if (!vma)
+ pr_debug("vma not found\n");
+ else if (vma->vm_flags & VM_WRITE)
+ pr_debug("VM_WRITE without VM_READ is not
supported");
+
+ s = max(addr >> PAGE_SHIFT, prange->start);
+ e = s + npages - 1;
+ r = svm_range_unmap_from_gpus(prange, s, e,
+
KFD_SVM_UNMAP_TRIGGER_UNMAP_FROM_CPU);
+ svm_range_unlock(prange);
+ /* If unmap returns non-zero, we'll bail on the next
for loop
+ * iteration, so just leave r and continue
+ */
+ addr = next;
+ continue;
+ }
- hmm_range = kzalloc(sizeof(*hmm_range), GFP_KERNEL);
- if (unlikely(!hmm_range)) {
- r = -ENOMEM;
- } else {
- WRITE_ONCE(p->svms.faulting_task, current);
- r =
amdgpu_hmm_range_get_pages(&prange->notifier, addr, npages,
- readonly, owner,
- hmm_range);
- WRITE_ONCE(p->svms.faulting_task, NULL);
- if (r) {
- kfree(hmm_range);
- hmm_range = NULL;
- pr_debug("failed %d to get svm range
pages\n", r);
- }
- }
+ readonly = !(vma->vm_flags & VM_WRITE);
+
+ hmm_range = kzalloc(sizeof(*hmm_range), GFP_KERNEL);
+ if (unlikely(!hmm_range)) {
+ r = -ENOMEM;
} else {
- r = -EFAULT;
+ WRITE_ONCE(p->svms.faulting_task, current);
+ r = amdgpu_hmm_range_get_pages(&prange->notifier, addr,
npages,
+ readonly, owner,
+ hmm_range);
+ WRITE_ONCE(p->svms.faulting_task, NULL);
+ if (r) {
+ kfree(hmm_range);
+ hmm_range = NULL;
+ pr_debug("failed %d to get svm range pages\n",
r);
+ }
}
if (!r) {
