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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id x4-20020a056902102400b00b9def138173sm3425234ybt.1.2023.05.09.21.42.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 21:42:54 -0700 (PDT) Date: Tue, 9 May 2023 21:42:44 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Andrew Morton Subject: [PATCH 01/23] arm: allow pte_offset_map[_lock]() to fail In-Reply-To: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> Message-ID: <5011977-d876-6a24-a3fc-c7e6a02877b8@google.com> References: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-ia64@vger.kernel.org, David Hildenbrand , Catalin Marinas , Qi Zheng , linux-kernel@vger.kernel.org, Max Filippov , sparclinux@vger.kernel.org, linux-riscv@lists.infradead.org, Claudio Imbrenda , Will Deacon , Greg Ungerer , linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, Helge Deller , x86@kernel.org, Russell King , Matthew Wilcox , Geert Uytterhoeven , Christian Borntraeger , Alexandre Ghiti , Heiko Carstens , linux-m68k@lists.linux-m68k.org, John Paul Adrian Glaubitz , John David Anglin , Suren Baghdasaryan , linux-arm-kernel@lists.infradead.org, Chris Zankel , Michal Simek , Thomas Bogendoerfer , linux-parisc@vger.kernel.org, linux-mm@kvack.org, linux-mips@vger.kernel.org, Palmer Dabbelt , "Kirill A. Shutemov" , "Aneesh Kumar K.V" , linuxppc-dev@lists.ozlabs.org, "David S. Miller" , Mike Rapoport , Mike Kravetz Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" In rare transient cases, not yet made possible, pte_offset_map() and pte_offset_map_lock() may not find a page table: handle appropriately. Signed-off-by: Hugh Dickins --- arch/arm/lib/uaccess_with_memcpy.c | 3 +++ arch/arm/mm/fault-armv.c | 5 ++++- arch/arm/mm/fault.c | 3 +++ 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c index e4c2677cc1e9..2f6163f05e93 100644 --- a/arch/arm/lib/uaccess_with_memcpy.c +++ b/arch/arm/lib/uaccess_with_memcpy.c @@ -74,6 +74,9 @@ pin_page_for_write(const void __user *_addr, pte_t **ptep, spinlock_t **ptlp) return 0; pte = pte_offset_map_lock(current->mm, pmd, addr, &ptl); + if (unlikely(!pte)) + return 0; + if (unlikely(!pte_present(*pte) || !pte_young(*pte) || !pte_write(*pte) || !pte_dirty(*pte))) { pte_unmap_unlock(pte, ptl); diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c index 0e49154454a6..ca5302b0b7ee 100644 --- a/arch/arm/mm/fault-armv.c +++ b/arch/arm/mm/fault-armv.c @@ -117,8 +117,11 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address, * must use the nested version. This also means we need to * open-code the spin-locking. */ - ptl = pte_lockptr(vma->vm_mm, pmd); pte = pte_offset_map(pmd, address); + if (!pte) + return 0; + + ptl = pte_lockptr(vma->vm_mm, pmd); do_pte_lock(ptl); ret = do_adjust_pte(vma, address, pfn, pte); diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index 2418f1efabd8..83598649a094 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -85,6 +85,9 @@ void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr) break; pte = pte_offset_map(pmd, addr); + if (!pte) + break; + pr_cont(", *pte=%08llx", (long long)pte_val(*pte)); #ifndef CONFIG_ARM_LPAE pr_cont(", *ppte=%08llx",