linux-kernel - [PATCH v1 13/16] mm: Don't skip arch_sync_kernel

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Message-ID: <20250205151003.88959-14-ryan.roberts@arm.com>
Date: Wed,  5 Feb 2025 15:09:53 +0000
From: Ryan Roberts <ryan.roberts@....com>
To: Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Muchun Song <muchun.song@...ux.dev>,
	Pasha Tatashin <pasha.tatashin@...een.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Uladzislau Rezki <urezki@...il.com>,
	Christoph Hellwig <hch@...radead.org>,
	Mark Rutland <mark.rutland@....com>,
	Ard Biesheuvel <ardb@...nel.org>,
	Anshuman Khandual <anshuman.khandual@....com>,
	Dev Jain <dev.jain@....com>,
	Alexandre Ghiti <alexghiti@...osinc.com>,
	Steve Capper <steve.capper@...aro.org>,
	Kevin Brodsky <kevin.brodsky@....com>
Cc: Ryan Roberts <ryan.roberts@....com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: [PATCH v1 13/16] mm: Don't skip arch_sync_kernel_mappings() in error paths

Fix callers that previously skipped calling arch_sync_kernel_mappings()
if an error occurred during a pgtable update. The call is still required
to sync any pgtable updates that may have occurred prior to hitting the
error condition.

These are theoretical bugs discovered during code review.

Cc: <stable@...r.kernel.org>
Fixes: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified")
Fixes: 0c95cba49255 ("mm: apply_to_pte_range warn and fail if a large pte is encountered")
Signed-off-by: Ryan Roberts <ryan.roberts@....com>
---
 mm/memory.c  | 6 ++++--
 mm/vmalloc.c | 4 ++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 539c0f7c6d54..a15f7dd500ea 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3040,8 +3040,10 @@ static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
 		next = pgd_addr_end(addr, end);
 		if (pgd_none(*pgd) && !create)
 			continue;
-		if (WARN_ON_ONCE(pgd_leaf(*pgd)))
-			return -EINVAL;
+		if (WARN_ON_ONCE(pgd_leaf(*pgd))) {
+			err = -EINVAL;
+			break;
+		}
 		if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) {
 			if (!create)
 				continue;
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 6111ce900ec4..68950b1824d0 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -604,13 +604,13 @@ static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
 			mask |= PGTBL_PGD_MODIFIED;
 		err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
 		if (err)
-			return err;
+			break;
 	} while (pgd++, addr = next, addr != end);
 
 	if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
 		arch_sync_kernel_mappings(start, end);
 
-	return 0;
+	return err;
 }
 
 /*
-- 
2.43.0