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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id c205-20020a814ed6000000b005688ca40c4bsm291663ywb.61.2023.06.08.18.27.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Jun 2023 18:27:56 -0700 (PDT) Date: Thu, 8 Jun 2023 18:27:52 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Andrew Morton cc: Mike Kravetz , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Yang Shi , Mel Gorman , Peter Xu , Peter Zijlstra , Will Deacon , Yu Zhao , Alistair Popple , Ralph Campbell , Ira Weiny , Steven Price , SeongJae Park , Lorenzo Stoakes , Huang Ying , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Jason Gunthorpe , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , Ryan Roberts , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2 16/32] mm/debug_vm_pgtable,page_table_check: warn pte map fails In-Reply-To: Message-ID: <3ea9e4f-e5cf-d7d9-4c2-291b3c5a3636@google.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Hugh Dickins --- mm/debug_vm_pgtable.c | 9 ++++++++- mm/page_table_check.c | 2 ++ 2 files changed, 10 insertions(+), 1 deletion(-) 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); diff --git a/mm/page_table_check.c b/mm/page_table_check.c index f2baf97d5f38..b743a2f6bce0 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -246,6 +246,8 @@ void __page_table_check_pte_clear_range(struct mm_struct *mm, pte_t *ptep = pte_offset_map(&pmd, addr); unsigned long i; + if (WARN_ON(!ptep)) + return; for (i = 0; i < PTRS_PER_PTE; i++) { __page_table_check_pte_clear(mm, addr, *ptep); addr += PAGE_SIZE; -- 2.35.3