Hello Lorenzo Stoakes,
The patch eca1a00155df: "mm/gup: remove vmas parameter from
get_user_pages_remote()" from May 14, 2023, leads to the following
Smatch static checker warning:
mm/memory.c:5617 __access_remote_vm()
error: uninitialized symbol 'vma'.
mm/memory.c
5590 int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
5591 int len, unsigned int gup_flags)
5592 {
5593 void *old_buf = buf;
5594 int write = gup_flags & FOLL_WRITE;
5595
5596 if (mmap_read_lock_killable(mm))
5597 return 0;
5598
5599 /* ignore errors, just check how much was successfully transferred */
5600 while (len) {
5601 int bytes, offset;
5602 void *maddr;
5603 struct vm_area_struct *vma;
5604 struct page *page = get_user_page_vma_remote(mm, addr,
5605 gup_flags, &vma);
5606
5607 if (IS_ERR_OR_NULL(page)) {
If page is either an error pointer or NULL then
5608 int ret = 0;
5609
5610 #ifndef CONFIG_HAVE_IOREMAP_PROT
5611 break;
5612 #else
5613 /*
5614 * Check if this is a VM_IO | VM_PFNMAP VMA, which
5615 * we can access using slightly different code.
5616 */
--> 5617 if (!vma)
that means vma is unitialized.
5618 break;
5619 if (vma->vm_ops && vma->vm_ops->access)
5620 ret = vma->vm_ops->access(vma, addr, buf,
5621 len, write);
5622 if (ret <= 0)
5623 break;
5624 bytes = ret;
5625 #endif
5626 } else {
5627 bytes = len;
5628 offset = addr & (PAGE_SIZE-1);
5629 if (bytes > PAGE_SIZE-offset)
5630 bytes = PAGE_SIZE-offset;
5631
5632 maddr = kmap(page);
5633 if (write) {
5634 copy_to_user_page(vma, page, addr,
5635 maddr + offset, buf, bytes);
5636 set_page_dirty_lock(page);
5637 } else {
5638 copy_from_user_page(vma, page, addr,
5639 buf, maddr + offset, bytes);
5640 }
5641 kunmap(page);
5642 put_page(page);
5643 }
5644 len -= bytes;
5645 buf += bytes;
5646 addr += bytes;
5647 }
5648 mmap_read_unlock(mm);
5649
5650 return buf - old_buf;
5651 }
regards,
dan carpenter
