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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id 23-20020a250d17000000b00b9e4a9b91b9sm3508848ybn.30.2023.05.09.21.57.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 21:57:47 -0700 (PDT) Date: Tue, 9 May 2023 21:57:44 -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 , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Greg Ungerer , Michal Simek , Thomas Bogendoerfer , Helge Deller , John David Anglin , "Aneesh Kumar K.V" , Michael Ellerman , Alexandre Ghiti , Palmer Dabbelt , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda , John Paul Adrian Glaubitz , "David S. Miller" , Chris Zankel , Max Filippov , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 12/23] powerpc: allow pte_offset_map[_lock]() to fail In-Reply-To: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> Message-ID: References: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org In rare transient cases, not yet made possible, pte_offset_map() and pte_offset_map_lock() may not find a page table: handle appropriately. Balance successful pte_offset_map() with pte_unmap() where omitted. Signed-off-by: Hugh Dickins --- arch/powerpc/mm/book3s64/hash_tlb.c | 4 ++++ arch/powerpc/mm/book3s64/subpage_prot.c | 2 ++ arch/powerpc/xmon/xmon.c | 5 ++++- 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c index a64ea0a7ef96..21fcad97ae80 100644 --- a/arch/powerpc/mm/book3s64/hash_tlb.c +++ b/arch/powerpc/mm/book3s64/hash_tlb.c @@ -239,12 +239,16 @@ void flush_hash_table_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long local_irq_save(flags); arch_enter_lazy_mmu_mode(); start_pte = pte_offset_map(pmd, addr); + if (!start_pte) + goto out; for (pte = start_pte; pte < start_pte + PTRS_PER_PTE; pte++) { unsigned long pteval = pte_val(*pte); if (pteval & H_PAGE_HASHPTE) hpte_need_flush(mm, addr, pte, pteval, 0); addr += PAGE_SIZE; } + pte_unmap(start_pte); +out: arch_leave_lazy_mmu_mode(); local_irq_restore(flags); } diff --git a/arch/powerpc/mm/book3s64/subpage_prot.c b/arch/powerpc/mm/book3s64/subpage_prot.c index b75a9fb99599..0dc85556dec5 100644 --- a/arch/powerpc/mm/book3s64/subpage_prot.c +++ b/arch/powerpc/mm/book3s64/subpage_prot.c @@ -71,6 +71,8 @@ static void hpte_flush_range(struct mm_struct *mm, unsigned long addr, if (pmd_none(*pmd)) return; pte = pte_offset_map_lock(mm, pmd, addr, &ptl); + if (!pte) + return; arch_enter_lazy_mmu_mode(); for (; npages > 0; --npages) { pte_update(mm, addr, pte, 0, 0, 0); diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 728d3c257e4a..69447bdf0bcf 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -3376,12 +3376,15 @@ static void show_pte(unsigned long addr) printf("pmdp @ 0x%px = 0x%016lx\n", pmdp, pmd_val(*pmdp)); ptep = pte_offset_map(pmdp, addr); - if (pte_none(*ptep)) { + if (!ptep || pte_none(*ptep)) { + if (ptep) + pte_unmap(ptep); printf("no valid PTE\n"); return; } format_pte(ptep, pte_val(*ptep)); + pte_unmap(ptep); sync(); __delay(200);