From c0e296f257671ba10249630fe58026f29e4804d9 Mon Sep 17 00:00:00 2001 From: Stanislav Kinsburskii Date: Tue, 17 Mar 2026 15:04:55 +0000 Subject: [PATCH] mshv: Fix error handling in mshv_region_pin The current error handling has two issues: First, pin_user_pages_fast() can return a short pin count (less than requested but greater than zero) when it cannot pin all requested pages. This is treated as success, leading to partially pinned regions being used, which causes memory corruption. Second, when an error occurs mid-loop, already pinned pages from the current batch are not properly accounted for before calling mshv_region_invalidate_pages(), causing a page reference leak. Treat short pins as errors and fix partial batch accounting before cleanup. Signed-off-by: Stanislav Kinsburskii Reviewed-by: Michael Kelley Signed-off-by: Wei Liu --- drivers/hv/mshv_regions.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/hv/mshv_regions.c b/drivers/hv/mshv_regions.c index c28aac0726de..fdffd4f002f6 100644 --- a/drivers/hv/mshv_regions.c +++ b/drivers/hv/mshv_regions.c @@ -314,15 +314,17 @@ int mshv_region_pin(struct mshv_mem_region *region) ret = pin_user_pages_fast(userspace_addr, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages); - if (ret < 0) + if (ret != nr_pages) goto release_pages; } return 0; release_pages: + if (ret > 0) + done_count += ret; mshv_region_invalidate_pages(region, 0, done_count); - return ret; + return ret < 0 ? ret : -ENOMEM; } static int mshv_region_chunk_unmap(struct mshv_mem_region *region,