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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id t67-20020a818346000000b0055a503ca1e8sm1804176ywf.109.2023.05.21.22.08.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 21 May 2023 22:08:56 -0700 (PDT) Date: Sun, 21 May 2023 22:08:53 -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 , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Jason Gunthorpe , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 16/31] mm/debug_vm_pgtable,page_table_check: warn pte map fails In-Reply-To: <68a97fbe-5c1e-7ac6-72c-7b9c6290b370@google.com> Message-ID: <87c0e8cc-85c0-806e-da9f-b7b3cacde7d@google.com> References: <68a97fbe-5c1e-7ac6-72c-7b9c6290b370@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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_de= bug_args *args) return; =20 pr_debug("Validating PTE advanced\n"); + if (WARN_ON(!args->ptep)) + return; + pte =3D 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 =3D __pte(pte_val(pte) | RANDOM_ORVALUE); #endif @@ -1377,7 +1383,8 @@ static int __init debug_vm_pgtable(void) args.ptep =3D 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); =20 ptl =3D 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 25d8610c0042..0c511330dbc9 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -240,6 +240,8 @@ void __page_table_check_pte_clear_range(struct mm_struc= t *mm, pte_t *ptep =3D pte_offset_map(&pmd, addr); unsigned long i; =20 + if (WARN_ON(!ptep)) + return; for (i =3D 0; i < PTRS_PER_PTE; i++) { __page_table_check_pte_clear(mm, addr, *ptep); addr +=3D PAGE_SIZE; --=20 2.35.3