mm/debug_vm_pgtable,page_table_check: warn pte map fails

Failures here would be surprising: pte_advanced_tests() and
pte_clear_tests() and __page_table_check_pte_clear_range() each issue a
warning if pte_offset_map() or pte_offset_map_lock() fails.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Hugh Dickins <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Axel Rasmussen <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Ira Weiny <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Mike Rapoport (IBM) <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Qi Zheng <[email protected]>
Cc: Ralph Campbell <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: SeongJae Park <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Steven Price <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Thomas Hellström <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Yu Zhao <[email protected]>
Cc: Zack Rusin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 8 insertions, 1 deletions

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index c54177aabebd..ee119e33fef1 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -138,6 +138,9 @@ static void __init pte_advanced_tests(struct pgtable_debug_args *args)
 		return;
 
 	pr_debug("Validating PTE advanced\n");
+	if (WARN_ON(!args->ptep))
+		return;
+
 	pte = pfn_pte(args->pte_pfn, args->page_prot);
 	set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 	flush_dcache_page(page);
@@ -619,6 +622,9 @@ static void __init pte_clear_tests(struct pgtable_debug_args *args)
 	 * the unexpected overhead of cache flushing is acceptable.
 	 */
 	pr_debug("Validating PTE clear\n");
+	if (WARN_ON(!args->ptep))
+		return;
+
 #ifndef CONFIG_RISCV
 	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
 #endif
@@ -1377,7 +1383,8 @@ static int __init debug_vm_pgtable(void)
 	args.ptep = pte_offset_map_lock(args.mm, args.pmdp, args.vaddr, &ptl);
 	pte_clear_tests(&args);
 	pte_advanced_tests(&args);
-	pte_unmap_unlock(args.ptep, ptl);
+	if (args.ptep)
+		pte_unmap_unlock(args.ptep, ptl);
 
 	ptl = pmd_lock(args.mm, args.pmdp);
 	pmd_clear_tests(&args);