On 2023-01-11 06:38, yf.wang@mediatek.com wrote:

From: Yunfei Wang yf.wang@mediatek.com

In __alloc_and_insert_iova_range, there is an issue that retry_pfn overflows. The value of iovad->anchor.pfn_hi is ~0UL, then when iovad->cached_node is iovad->anchor, curr_iova->pfn_hi + 1 will overflow. As a result, if the retry logic is executed, low_pfn is updated to 0, and then new_pfn < low_pfn returns false to make the allocation successful.

This issue occurs in the following two situations:

1. The first iova size exceeds the domain size. When initializing

iova domain, iovad->cached_node is assigned as iovad->anchor. For example, the iova domain size is 10M, start_pfn is 0x1_F000_0000, and the iova size allocated for the first time is 11M. The following is the log information, new->pfn_lo is smaller than iovad->cached_node.

Example log as follows: [ 223.798112][T1705487] sh: [name:iova&]__alloc_and_insert_iova_range start_pfn:0x1f0000,retry_pfn:0x0,size:0xb00,limit_pfn:0x1f0a00 [ 223.799590][T1705487] sh: [name:iova&]__alloc_and_insert_iova_range success start_pfn:0x1f0000,new->pfn_lo:0x1efe00,new->pfn_hi:0x1f08ff

2. The node with the largest iova->pfn_lo value in the iova domain

is deleted, iovad->cached_node will be updated to iovad->anchor, and then the alloc iova size exceeds the maximum iova size that can be allocated in the domain.

After judging that retry_pfn is less than limit_pfn, call retry_pfn+1 to fix the overflow issue.

Signed-off-by: jianjiao zeng jianjiao.zeng@mediatek.com Signed-off-by: Yunfei Wang yf.wang@mediatek.com Cc: stable@vger.kernel.org # 5.15.*

Fixes: 4e89dce72521 ("iommu/iova: Retry from last rb tree node if iova search fails")

Acked-by: Robin Murphy robin.murphy@arm.com

---

v2: Update patch 1. Cc stable@vger.kernel.org This patch needs to be merged stable branch, add stable@vger.kernel.org in mail list. 2. Refer robin's suggestion to update patch.

---

drivers/iommu/iova.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index a44ad92fc5eb..fe452ce46642 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -197,7 +197,7 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, curr = __get_cached_rbnode(iovad, limit_pfn); curr_iova = to_iova(curr);

• retry_pfn = curr_iova->pfn_hi + 1;

• retry_pfn = curr_iova->pfn_hi;

retry: do { @@ -211,7 +211,7 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, if (high_pfn < size || new_pfn < low_pfn) { if (low_pfn == iovad->start_pfn && retry_pfn < limit_pfn) { high_pfn = limit_pfn;

• 	low_pfn = retry_pfn;
  

• 	low_pfn = retry_pfn + 1;
  curr = iova_find_limit(iovad, limit_pfn);
  curr_iova = to_iova(curr);
  goto retry;