From: Li Zhe <lizhe.67@bytedance.com>
Introduce a new member has_rsvd for struct vfio_dma. This member is
used to indicate whether there are any reserved or invalid pfns in
the region represented by this vfio_dma. If it is true, it indicates
that there is at least one pfn in this region that is either reserved
or invalid.
Signed-off-by: Li Zhe <lizhe.67@bytedance.com>
---
drivers/vfio/vfio_iommu_type1.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 330fff4fe96d..a02bc340c112 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -92,6 +92,7 @@ struct vfio_dma {
bool iommu_mapped;
bool lock_cap; /* capable(CAP_IPC_LOCK) */
bool vaddr_invalid;
+ bool has_rsvd; /* has 1 or more rsvd pfns */
struct task_struct *task;
struct rb_root pfn_list; /* Ex-user pinned pfn list */
unsigned long *bitmap;
@@ -784,6 +785,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
}
out:
+ dma->has_rsvd |= rsvd;
ret = vfio_lock_acct(dma, lock_acct, false);
unpin_out:
--
2.20.1Hi,
kernel test robot noticed the following build warnings:
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/lizhe-67-bytedance-com/vfio-type1-optimize-vfio_pin_pages_remote-for-large-folios/20250630-152849
base: https://github.com/awilliam/linux-vfio.git next
patch link: https://lore.kernel.org/r/20250630072518.31846-4-lizhe.67%40bytedance.com
patch subject: [PATCH 3/4] vfio/type1: introduce a new member has_rsvd for struct vfio_dma
config: x86_64-randconfig-161-20250701 (https://download.01.org/0day-ci/archive/20250701/202507012121.wkDLcDXn-lkp@intel.com/config)
compiler: clang version 20.1.7 (https://github.com/llvm/llvm-project 6146a88f60492b520a36f8f8f3231e15f3cc6082)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202507012121.wkDLcDXn-lkp@intel.com/
New smatch warnings:
drivers/vfio/vfio_iommu_type1.c:788 vfio_pin_pages_remote() error: uninitialized symbol 'rsvd'.
Old smatch warnings:
drivers/vfio/vfio_iommu_type1.c:2376 vfio_iommu_type1_attach_group() warn: '&group->next' not removed from list
vim +/rsvd +788 drivers/vfio/vfio_iommu_type1.c
8f0d5bb95f763c Kirti Wankhede 2016-11-17 684 static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
0635559233434a Alex Williamson 2025-02-18 685 unsigned long npage, unsigned long *pfn_base,
4b6c33b3229678 Daniel Jordan 2021-02-19 686 unsigned long limit, struct vfio_batch *batch)
73fa0d10d077d9 Alex Williamson 2012-07-31 687 {
4d83de6da265cd Daniel Jordan 2021-02-19 688 unsigned long pfn;
4d83de6da265cd Daniel Jordan 2021-02-19 689 struct mm_struct *mm = current->mm;
6c38c055cc4c0a Alex Williamson 2016-12-30 690 long ret, pinned = 0, lock_acct = 0;
89c29def6b0101 Alex Williamson 2018-06-02 691 bool rsvd;
a54eb55045ae9b Kirti Wankhede 2016-11-17 692 dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
166fd7d94afdac Alex Williamson 2013-06-21 693
6c38c055cc4c0a Alex Williamson 2016-12-30 694 /* This code path is only user initiated */
4d83de6da265cd Daniel Jordan 2021-02-19 695 if (!mm)
166fd7d94afdac Alex Williamson 2013-06-21 696 return -ENODEV;
73fa0d10d077d9 Alex Williamson 2012-07-31 697
4d83de6da265cd Daniel Jordan 2021-02-19 698 if (batch->size) {
4d83de6da265cd Daniel Jordan 2021-02-19 699 /* Leftover pages in batch from an earlier call. */
4d83de6da265cd Daniel Jordan 2021-02-19 700 *pfn_base = page_to_pfn(batch->pages[batch->offset]);
4d83de6da265cd Daniel Jordan 2021-02-19 701 pfn = *pfn_base;
89c29def6b0101 Alex Williamson 2018-06-02 702 rsvd = is_invalid_reserved_pfn(*pfn_base);
4d83de6da265cd Daniel Jordan 2021-02-19 703 } else {
4d83de6da265cd Daniel Jordan 2021-02-19 704 *pfn_base = 0;
5c6c2b21ecc9ad Alex Williamson 2013-06-21 705 }
5c6c2b21ecc9ad Alex Williamson 2013-06-21 706
eb996eec783c1e Alex Williamson 2025-02-18 707 if (unlikely(disable_hugepages))
eb996eec783c1e Alex Williamson 2025-02-18 708 npage = 1;
eb996eec783c1e Alex Williamson 2025-02-18 709
4d83de6da265cd Daniel Jordan 2021-02-19 710 while (npage) {
4d83de6da265cd Daniel Jordan 2021-02-19 711 if (!batch->size) {
4d83de6da265cd Daniel Jordan 2021-02-19 712 /* Empty batch, so refill it. */
eb996eec783c1e Alex Williamson 2025-02-18 713 ret = vaddr_get_pfns(mm, vaddr, npage, dma->prot,
eb996eec783c1e Alex Williamson 2025-02-18 714 &pfn, batch);
be16c1fd99f41a Daniel Jordan 2021-02-19 715 if (ret < 0)
4d83de6da265cd Daniel Jordan 2021-02-19 716 goto unpin_out;
166fd7d94afdac Alex Williamson 2013-06-21 717
4d83de6da265cd Daniel Jordan 2021-02-19 718 if (!*pfn_base) {
4d83de6da265cd Daniel Jordan 2021-02-19 719 *pfn_base = pfn;
4d83de6da265cd Daniel Jordan 2021-02-19 720 rsvd = is_invalid_reserved_pfn(*pfn_base);
4d83de6da265cd Daniel Jordan 2021-02-19 721 }
If "*pfn_base" is true then "rsvd" is uninitialized.
eb996eec783c1e Alex Williamson 2025-02-18 722
eb996eec783c1e Alex Williamson 2025-02-18 723 /* Handle pfnmap */
eb996eec783c1e Alex Williamson 2025-02-18 724 if (!batch->size) {
eb996eec783c1e Alex Williamson 2025-02-18 725 if (pfn != *pfn_base + pinned || !rsvd)
eb996eec783c1e Alex Williamson 2025-02-18 726 goto out;
goto out;
eb996eec783c1e Alex Williamson 2025-02-18 727
eb996eec783c1e Alex Williamson 2025-02-18 728 pinned += ret;
eb996eec783c1e Alex Williamson 2025-02-18 729 npage -= ret;
eb996eec783c1e Alex Williamson 2025-02-18 730 vaddr += (PAGE_SIZE * ret);
eb996eec783c1e Alex Williamson 2025-02-18 731 iova += (PAGE_SIZE * ret);
eb996eec783c1e Alex Williamson 2025-02-18 732 continue;
eb996eec783c1e Alex Williamson 2025-02-18 733 }
166fd7d94afdac Alex Williamson 2013-06-21 734 }
166fd7d94afdac Alex Williamson 2013-06-21 735
4d83de6da265cd Daniel Jordan 2021-02-19 736 /*
eb996eec783c1e Alex Williamson 2025-02-18 737 * pfn is preset for the first iteration of this inner loop
eb996eec783c1e Alex Williamson 2025-02-18 738 * due to the fact that vaddr_get_pfns() needs to provide the
eb996eec783c1e Alex Williamson 2025-02-18 739 * initial pfn for pfnmaps. Therefore to reduce redundancy,
eb996eec783c1e Alex Williamson 2025-02-18 740 * the next pfn is fetched at the end of the loop.
eb996eec783c1e Alex Williamson 2025-02-18 741 * A PageReserved() page could still qualify as page backed
eb996eec783c1e Alex Williamson 2025-02-18 742 * and rsvd here, and therefore continues to use the batch.
4d83de6da265cd Daniel Jordan 2021-02-19 743 */
4d83de6da265cd Daniel Jordan 2021-02-19 744 while (true) {
6a2d9b72168041 Li Zhe 2025-06-30 745 long nr_pages, acct_pages = 0;
6a2d9b72168041 Li Zhe 2025-06-30 746
4d83de6da265cd Daniel Jordan 2021-02-19 747 if (pfn != *pfn_base + pinned ||
4d83de6da265cd Daniel Jordan 2021-02-19 748 rsvd != is_invalid_reserved_pfn(pfn))
4d83de6da265cd Daniel Jordan 2021-02-19 749 goto out;
4d83de6da265cd Daniel Jordan 2021-02-19 750
6a2d9b72168041 Li Zhe 2025-06-30 751 nr_pages = contig_pages(dma, batch, iova);
6a2d9b72168041 Li Zhe 2025-06-30 752 if (!rsvd) {
6a2d9b72168041 Li Zhe 2025-06-30 753 acct_pages = nr_pages;
6a2d9b72168041 Li Zhe 2025-06-30 754 acct_pages -= vpfn_pages(dma, iova, nr_pages);
6a2d9b72168041 Li Zhe 2025-06-30 755 }
6a2d9b72168041 Li Zhe 2025-06-30 756
4d83de6da265cd Daniel Jordan 2021-02-19 757 /*
4d83de6da265cd Daniel Jordan 2021-02-19 758 * Reserved pages aren't counted against the user,
4d83de6da265cd Daniel Jordan 2021-02-19 759 * externally pinned pages are already counted against
4d83de6da265cd Daniel Jordan 2021-02-19 760 * the user.
4d83de6da265cd Daniel Jordan 2021-02-19 761 */
6a2d9b72168041 Li Zhe 2025-06-30 762 if (acct_pages) {
48d8476b41eed6 Alex Williamson 2018-05-11 763 if (!dma->lock_cap &&
6a2d9b72168041 Li Zhe 2025-06-30 764 mm->locked_vm + lock_acct + acct_pages > limit) {
6c38c055cc4c0a Alex Williamson 2016-12-30 765 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
6c38c055cc4c0a Alex Williamson 2016-12-30 766 __func__, limit << PAGE_SHIFT);
0cfef2b7410b64 Alex Williamson 2017-04-13 767 ret = -ENOMEM;
0cfef2b7410b64 Alex Williamson 2017-04-13 768 goto unpin_out;
166fd7d94afdac Alex Williamson 2013-06-21 769 }
6a2d9b72168041 Li Zhe 2025-06-30 770 lock_acct += acct_pages;
a54eb55045ae9b Kirti Wankhede 2016-11-17 771 }
4d83de6da265cd Daniel Jordan 2021-02-19 772
6a2d9b72168041 Li Zhe 2025-06-30 773 pinned += nr_pages;
6a2d9b72168041 Li Zhe 2025-06-30 774 npage -= nr_pages;
6a2d9b72168041 Li Zhe 2025-06-30 775 vaddr += PAGE_SIZE * nr_pages;
6a2d9b72168041 Li Zhe 2025-06-30 776 iova += PAGE_SIZE * nr_pages;
6a2d9b72168041 Li Zhe 2025-06-30 777 batch->offset += nr_pages;
6a2d9b72168041 Li Zhe 2025-06-30 778 batch->size -= nr_pages;
4d83de6da265cd Daniel Jordan 2021-02-19 779
4d83de6da265cd Daniel Jordan 2021-02-19 780 if (!batch->size)
4d83de6da265cd Daniel Jordan 2021-02-19 781 break;
4d83de6da265cd Daniel Jordan 2021-02-19 782
4d83de6da265cd Daniel Jordan 2021-02-19 783 pfn = page_to_pfn(batch->pages[batch->offset]);
4d83de6da265cd Daniel Jordan 2021-02-19 784 }
a54eb55045ae9b Kirti Wankhede 2016-11-17 785 }
166fd7d94afdac Alex Williamson 2013-06-21 786
6c38c055cc4c0a Alex Williamson 2016-12-30 787 out:
20448310d6b71d Li Zhe 2025-06-30 @788 dma->has_rsvd |= rsvd;
^^^^
48d8476b41eed6 Alex Williamson 2018-05-11 789 ret = vfio_lock_acct(dma, lock_acct, false);
0cfef2b7410b64 Alex Williamson 2017-04-13 790
0cfef2b7410b64 Alex Williamson 2017-04-13 791 unpin_out:
be16c1fd99f41a Daniel Jordan 2021-02-19 792 if (ret < 0) {
4d83de6da265cd Daniel Jordan 2021-02-19 793 if (pinned && !rsvd) {
0cfef2b7410b64 Alex Williamson 2017-04-13 794 for (pfn = *pfn_base ; pinned ; pfn++, pinned--)
0cfef2b7410b64 Alex Williamson 2017-04-13 795 put_pfn(pfn, dma->prot);
89c29def6b0101 Alex Williamson 2018-06-02 796 }
4d83de6da265cd Daniel Jordan 2021-02-19 797 vfio_batch_unpin(batch, dma);
0cfef2b7410b64 Alex Williamson 2017-04-13 798
0cfef2b7410b64 Alex Williamson 2017-04-13 799 return ret;
0cfef2b7410b64 Alex Williamson 2017-04-13 800 }
166fd7d94afdac Alex Williamson 2013-06-21 801
6c38c055cc4c0a Alex Williamson 2016-12-30 802 return pinned;
73fa0d10d077d9 Alex Williamson 2012-07-31 803 }
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Tue, 1 Jul 2025 18:13:48 +0300, dan.carpenter@linaro.org wrote:
> New smatch warnings:
> drivers/vfio/vfio_iommu_type1.c:788 vfio_pin_pages_remote() error: uninitialized symbol 'rsvd'.
>
> Old smatch warnings:
> drivers/vfio/vfio_iommu_type1.c:2376 vfio_iommu_type1_attach_group() warn: '&group->next' not removed from list
>
> vim +/rsvd +788 drivers/vfio/vfio_iommu_type1.c
>
> 8f0d5bb95f763c Kirti Wankhede 2016-11-17 684 static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
> 0635559233434a Alex Williamson 2025-02-18 685 unsigned long npage, unsigned long *pfn_base,
> 4b6c33b3229678 Daniel Jordan 2021-02-19 686 unsigned long limit, struct vfio_batch *batch)
> 73fa0d10d077d9 Alex Williamson 2012-07-31 687 {
> 4d83de6da265cd Daniel Jordan 2021-02-19 688 unsigned long pfn;
> 4d83de6da265cd Daniel Jordan 2021-02-19 689 struct mm_struct *mm = current->mm;
> 6c38c055cc4c0a Alex Williamson 2016-12-30 690 long ret, pinned = 0, lock_acct = 0;
> 89c29def6b0101 Alex Williamson 2018-06-02 691 bool rsvd;
> a54eb55045ae9b Kirti Wankhede 2016-11-17 692 dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
> 166fd7d94afdac Alex Williamson 2013-06-21 693
> 6c38c055cc4c0a Alex Williamson 2016-12-30 694 /* This code path is only user initiated */
> 4d83de6da265cd Daniel Jordan 2021-02-19 695 if (!mm)
> 166fd7d94afdac Alex Williamson 2013-06-21 696 return -ENODEV;
> 73fa0d10d077d9 Alex Williamson 2012-07-31 697
> 4d83de6da265cd Daniel Jordan 2021-02-19 698 if (batch->size) {
> 4d83de6da265cd Daniel Jordan 2021-02-19 699 /* Leftover pages in batch from an earlier call. */
> 4d83de6da265cd Daniel Jordan 2021-02-19 700 *pfn_base = page_to_pfn(batch->pages[batch->offset]);
> 4d83de6da265cd Daniel Jordan 2021-02-19 701 pfn = *pfn_base;
> 89c29def6b0101 Alex Williamson 2018-06-02 702 rsvd = is_invalid_reserved_pfn(*pfn_base);
When batch->size is not zero, we initialize rsvd here.
> 4d83de6da265cd Daniel Jordan 2021-02-19 703 } else {
> 4d83de6da265cd Daniel Jordan 2021-02-19 704 *pfn_base = 0;
When the value of batch->size is zero, we set the value of *pfn_base
to zero and do not initialize rsvd for the time being.
> 5c6c2b21ecc9ad Alex Williamson 2013-06-21 705 }
> 5c6c2b21ecc9ad Alex Williamson 2013-06-21 706
> eb996eec783c1e Alex Williamson 2025-02-18 707 if (unlikely(disable_hugepages))
> eb996eec783c1e Alex Williamson 2025-02-18 708 npage = 1;
> eb996eec783c1e Alex Williamson 2025-02-18 709
> 4d83de6da265cd Daniel Jordan 2021-02-19 710 while (npage) {
> 4d83de6da265cd Daniel Jordan 2021-02-19 711 if (!batch->size) {
> 4d83de6da265cd Daniel Jordan 2021-02-19 712 /* Empty batch, so refill it. */
> eb996eec783c1e Alex Williamson 2025-02-18 713 ret = vaddr_get_pfns(mm, vaddr, npage, dma->prot,
> eb996eec783c1e Alex Williamson 2025-02-18 714 &pfn, batch);
> be16c1fd99f41a Daniel Jordan 2021-02-19 715 if (ret < 0)
> 4d83de6da265cd Daniel Jordan 2021-02-19 716 goto unpin_out;
> 166fd7d94afdac Alex Williamson 2013-06-21 717
> 4d83de6da265cd Daniel Jordan 2021-02-19 718 if (!*pfn_base) {
> 4d83de6da265cd Daniel Jordan 2021-02-19 719 *pfn_base = pfn;
> 4d83de6da265cd Daniel Jordan 2021-02-19 720 rsvd = is_invalid_reserved_pfn(*pfn_base);
Therefore, for the first loop, when batch->size is zero, *pfn_base must
be zero, which will then lead to the initialization of rsvd.
> 4d83de6da265cd Daniel Jordan 2021-02-19 721 }
>
> If "*pfn_base" is true then "rsvd" is uninitialized.
>
> eb996eec783c1e Alex Williamson 2025-02-18 722
> eb996eec783c1e Alex Williamson 2025-02-18 723 /* Handle pfnmap */
> eb996eec783c1e Alex Williamson 2025-02-18 724 if (!batch->size) {
> eb996eec783c1e Alex Williamson 2025-02-18 725 if (pfn != *pfn_base + pinned || !rsvd)
> eb996eec783c1e Alex Williamson 2025-02-18 726 goto out;
>
> goto out;
>
> eb996eec783c1e Alex Williamson 2025-02-18 727
> eb996eec783c1e Alex Williamson 2025-02-18 728 pinned += ret;
> eb996eec783c1e Alex Williamson 2025-02-18 729 npage -= ret;
> eb996eec783c1e Alex Williamson 2025-02-18 730 vaddr += (PAGE_SIZE * ret);
> eb996eec783c1e Alex Williamson 2025-02-18 731 iova += (PAGE_SIZE * ret);
> eb996eec783c1e Alex Williamson 2025-02-18 732 continue;
> eb996eec783c1e Alex Williamson 2025-02-18 733 }
> 166fd7d94afdac Alex Williamson 2013-06-21 734 }
> 166fd7d94afdac Alex Williamson 2013-06-21 735
> 4d83de6da265cd Daniel Jordan 2021-02-19 736 /*
> eb996eec783c1e Alex Williamson 2025-02-18 737 * pfn is preset for the first iteration of this inner loop
> eb996eec783c1e Alex Williamson 2025-02-18 738 * due to the fact that vaddr_get_pfns() needs to provide the
> eb996eec783c1e Alex Williamson 2025-02-18 739 * initial pfn for pfnmaps. Therefore to reduce redundancy,
> eb996eec783c1e Alex Williamson 2025-02-18 740 * the next pfn is fetched at the end of the loop.
> eb996eec783c1e Alex Williamson 2025-02-18 741 * A PageReserved() page could still qualify as page backed
> eb996eec783c1e Alex Williamson 2025-02-18 742 * and rsvd here, and therefore continues to use the batch.
> 4d83de6da265cd Daniel Jordan 2021-02-19 743 */
> 4d83de6da265cd Daniel Jordan 2021-02-19 744 while (true) {
> 6a2d9b72168041 Li Zhe 2025-06-30 745 long nr_pages, acct_pages = 0;
> 6a2d9b72168041 Li Zhe 2025-06-30 746
> 4d83de6da265cd Daniel Jordan 2021-02-19 747 if (pfn != *pfn_base + pinned ||
> 4d83de6da265cd Daniel Jordan 2021-02-19 748 rsvd != is_invalid_reserved_pfn(pfn))
> 4d83de6da265cd Daniel Jordan 2021-02-19 749 goto out;
> 4d83de6da265cd Daniel Jordan 2021-02-19 750
> 6a2d9b72168041 Li Zhe 2025-06-30 751 nr_pages = contig_pages(dma, batch, iova);
> 6a2d9b72168041 Li Zhe 2025-06-30 752 if (!rsvd) {
> 6a2d9b72168041 Li Zhe 2025-06-30 753 acct_pages = nr_pages;
> 6a2d9b72168041 Li Zhe 2025-06-30 754 acct_pages -= vpfn_pages(dma, iova, nr_pages);
> 6a2d9b72168041 Li Zhe 2025-06-30 755 }
> 6a2d9b72168041 Li Zhe 2025-06-30 756
> 4d83de6da265cd Daniel Jordan 2021-02-19 757 /*
> 4d83de6da265cd Daniel Jordan 2021-02-19 758 * Reserved pages aren't counted against the user,
> 4d83de6da265cd Daniel Jordan 2021-02-19 759 * externally pinned pages are already counted against
> 4d83de6da265cd Daniel Jordan 2021-02-19 760 * the user.
> 4d83de6da265cd Daniel Jordan 2021-02-19 761 */
> 6a2d9b72168041 Li Zhe 2025-06-30 762 if (acct_pages) {
> 48d8476b41eed6 Alex Williamson 2018-05-11 763 if (!dma->lock_cap &&
> 6a2d9b72168041 Li Zhe 2025-06-30 764 mm->locked_vm + lock_acct + acct_pages > limit) {
> 6c38c055cc4c0a Alex Williamson 2016-12-30 765 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
> 6c38c055cc4c0a Alex Williamson 2016-12-30 766 __func__, limit << PAGE_SHIFT);
> 0cfef2b7410b64 Alex Williamson 2017-04-13 767 ret = -ENOMEM;
> 0cfef2b7410b64 Alex Williamson 2017-04-13 768 goto unpin_out;
> 166fd7d94afdac Alex Williamson 2013-06-21 769 }
> 6a2d9b72168041 Li Zhe 2025-06-30 770 lock_acct += acct_pages;
> a54eb55045ae9b Kirti Wankhede 2016-11-17 771 }
> 4d83de6da265cd Daniel Jordan 2021-02-19 772
> 6a2d9b72168041 Li Zhe 2025-06-30 773 pinned += nr_pages;
> 6a2d9b72168041 Li Zhe 2025-06-30 774 npage -= nr_pages;
> 6a2d9b72168041 Li Zhe 2025-06-30 775 vaddr += PAGE_SIZE * nr_pages;
> 6a2d9b72168041 Li Zhe 2025-06-30 776 iova += PAGE_SIZE * nr_pages;
> 6a2d9b72168041 Li Zhe 2025-06-30 777 batch->offset += nr_pages;
> 6a2d9b72168041 Li Zhe 2025-06-30 778 batch->size -= nr_pages;
> 4d83de6da265cd Daniel Jordan 2021-02-19 779
> 4d83de6da265cd Daniel Jordan 2021-02-19 780 if (!batch->size)
> 4d83de6da265cd Daniel Jordan 2021-02-19 781 break;
> 4d83de6da265cd Daniel Jordan 2021-02-19 782
> 4d83de6da265cd Daniel Jordan 2021-02-19 783 pfn = page_to_pfn(batch->pages[batch->offset]);
> 4d83de6da265cd Daniel Jordan 2021-02-19 784 }
> a54eb55045ae9b Kirti Wankhede 2016-11-17 785 }
> 166fd7d94afdac Alex Williamson 2013-06-21 786
> 6c38c055cc4c0a Alex Williamson 2016-12-30 787 out:
> 20448310d6b71d Li Zhe 2025-06-30 @788 dma->has_rsvd |= rsvd;
> ^^^^
In summary, it is likely to be a false alarm.
Please correct me if I am wrong.
Thanks,
Zhe
On Wed, Jul 02, 2025 at 11:47:20AM +0800, lizhe.67@bytedance.com wrote:
> On Tue, 1 Jul 2025 18:13:48 +0300, dan.carpenter@linaro.org wrote:
>
> > New smatch warnings:
> > drivers/vfio/vfio_iommu_type1.c:788 vfio_pin_pages_remote() error: uninitialized symbol 'rsvd'.
> >
> > Old smatch warnings:
> > drivers/vfio/vfio_iommu_type1.c:2376 vfio_iommu_type1_attach_group() warn: '&group->next' not removed from list
> >
> > vim +/rsvd +788 drivers/vfio/vfio_iommu_type1.c
> >
> > 8f0d5bb95f763c Kirti Wankhede 2016-11-17 684 static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
> > 0635559233434a Alex Williamson 2025-02-18 685 unsigned long npage, unsigned long *pfn_base,
> > 4b6c33b3229678 Daniel Jordan 2021-02-19 686 unsigned long limit, struct vfio_batch *batch)
> > 73fa0d10d077d9 Alex Williamson 2012-07-31 687 {
> > 4d83de6da265cd Daniel Jordan 2021-02-19 688 unsigned long pfn;
> > 4d83de6da265cd Daniel Jordan 2021-02-19 689 struct mm_struct *mm = current->mm;
> > 6c38c055cc4c0a Alex Williamson 2016-12-30 690 long ret, pinned = 0, lock_acct = 0;
> > 89c29def6b0101 Alex Williamson 2018-06-02 691 bool rsvd;
> > a54eb55045ae9b Kirti Wankhede 2016-11-17 692 dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
> > 166fd7d94afdac Alex Williamson 2013-06-21 693
> > 6c38c055cc4c0a Alex Williamson 2016-12-30 694 /* This code path is only user initiated */
> > 4d83de6da265cd Daniel Jordan 2021-02-19 695 if (!mm)
> > 166fd7d94afdac Alex Williamson 2013-06-21 696 return -ENODEV;
> > 73fa0d10d077d9 Alex Williamson 2012-07-31 697
> > 4d83de6da265cd Daniel Jordan 2021-02-19 698 if (batch->size) {
> > 4d83de6da265cd Daniel Jordan 2021-02-19 699 /* Leftover pages in batch from an earlier call. */
> > 4d83de6da265cd Daniel Jordan 2021-02-19 700 *pfn_base = page_to_pfn(batch->pages[batch->offset]);
> > 4d83de6da265cd Daniel Jordan 2021-02-19 701 pfn = *pfn_base;
> > 89c29def6b0101 Alex Williamson 2018-06-02 702 rsvd = is_invalid_reserved_pfn(*pfn_base);
>
> When batch->size is not zero, we initialize rsvd here.
>
> > 4d83de6da265cd Daniel Jordan 2021-02-19 703 } else {
> > 4d83de6da265cd Daniel Jordan 2021-02-19 704 *pfn_base = 0;
>
> When the value of batch->size is zero, we set the value of *pfn_base
> to zero and do not initialize rsvd for the time being.
>
> > 5c6c2b21ecc9ad Alex Williamson 2013-06-21 705 }
> > 5c6c2b21ecc9ad Alex Williamson 2013-06-21 706
> > eb996eec783c1e Alex Williamson 2025-02-18 707 if (unlikely(disable_hugepages))
> > eb996eec783c1e Alex Williamson 2025-02-18 708 npage = 1;
> > eb996eec783c1e Alex Williamson 2025-02-18 709
> > 4d83de6da265cd Daniel Jordan 2021-02-19 710 while (npage) {
> > 4d83de6da265cd Daniel Jordan 2021-02-19 711 if (!batch->size) {
> > 4d83de6da265cd Daniel Jordan 2021-02-19 712 /* Empty batch, so refill it. */
> > eb996eec783c1e Alex Williamson 2025-02-18 713 ret = vaddr_get_pfns(mm, vaddr, npage, dma->prot,
> > eb996eec783c1e Alex Williamson 2025-02-18 714 &pfn, batch);
> > be16c1fd99f41a Daniel Jordan 2021-02-19 715 if (ret < 0)
> > 4d83de6da265cd Daniel Jordan 2021-02-19 716 goto unpin_out;
> > 166fd7d94afdac Alex Williamson 2013-06-21 717
> > 4d83de6da265cd Daniel Jordan 2021-02-19 718 if (!*pfn_base) {
> > 4d83de6da265cd Daniel Jordan 2021-02-19 719 *pfn_base = pfn;
> > 4d83de6da265cd Daniel Jordan 2021-02-19 720 rsvd = is_invalid_reserved_pfn(*pfn_base);
>
> Therefore, for the first loop, when batch->size is zero, *pfn_base must
> be zero, which will then lead to the initialization of rsvd.
>
Yeah. :/
I don't know why this warning was printed honestly. Smatch is supposed
to figure that kind of thing out correctly. It isn't printed on my
system. I've tried deleting the cross function DB (which shouldn't
matter) and I'm using the published version of Smatch but I can't get it
to print. Ah well. My bad. Thanks for taking a look.
regards,
dan carpenter
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