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Tue, 4 Feb 2020 01:36:00 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0987F2086A; Tue, 4 Feb 2020 01:35:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580780160; bh=zDuJq4d+bq+FXSzU6oDN2i7sUTCTpf+eG/566fbFaXU=; h=Date:From:To:Subject:In-Reply-To:From; b=OPN17Clgtat/x9tbgvu/HiywbsvlbYKowGgnWU8QaueVGW5EIpCh+rQVUf2oQI/dt idDof5kOj8CqmTk5u1HjNkuDp1aPFnRNPbAjDLeoqlBvchZ76UuUhcNq18PkYIsNCb mWY16hGicZJeMYzwQo2ukiLGIVeN7ynzsEo3OyrE= Date: Mon, 03 Feb 2020 17:35:58 -0800 From: Andrew Morton To: akpm@linux-foundation.org, alex@ghiti.fr, aou@eecs.berkeley.edu, ard.biesheuvel@linaro.org, arnd@arndb.de, benh@kernel.crashing.org, borntraeger@de.ibm.com, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, davem@davemloft.net, gor@linux.ibm.com, heiko.carstens@de.ibm.com, hpa@zytor.com, james.morse@arm.com, jglisse@redhat.com, jhogan@kernel.org, kan.liang@linux.intel.com, linux-mm@kvack.org, linux@armlinux.org.uk, luto@kernel.org, mark.rutland@arm.com, mingo@redhat.com, mm-commits@vger.kernel.org, mpe@ellerman.id.au, paul.burton@mips.com, paul.walmsley@sifive.com, paulus@samba.org, peterz@infradead.org, ralf@linux-mips.org, steven.price@arm.com, tglx@linutronix.de, torvalds@linux-foundation.org, vgupta@synopsys.com, will@kernel.org, zong.li@sifive.com Subject: [patch 37/67] mm: pagewalk: fix termination condition in walk_pte_range() Message-ID: <20200204013558.7CnEuXSfm%akpm@linux-foundation.org> In-Reply-To: <20200203173311.6269a8be06a05e5a4aa08a93@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Steven Price Subject: mm: pagewalk: fix termination condition in walk_pte_range() If walk_pte_range() is called with a 'end' argument that is beyond the last page of memory (e.g. ~0UL) then the comparison between 'addr' and 'end' will always fail and the loop will be infinite. Instead change the comparison to >= while accounting for overflow. Link: http://lkml.kernel.org/r/20191218162402.45610-15-steven.price@arm.com Signed-off-by: Steven Price Cc: Albert Ou Cc: Alexandre Ghiti Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Dave Hansen Cc: David S. Miller Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: James Hogan Cc: James Morse Cc: Jerome Glisse Cc: "Liang, Kan" Cc: Mark Rutland Cc: Michael Ellerman Cc: Paul Burton Cc: Paul Mackerras Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Russell King Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vineet Gupta Cc: Will Deacon Cc: Zong Li Signed-off-by: Andrew Morton --- mm/pagewalk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/pagewalk.c~mm-pagewalk-fix-termination-condition-in-walk_pte_range +++ a/mm/pagewalk.c @@ -14,9 +14,9 @@ static int walk_pte_range_inner(pte_t *p err = ops->pte_entry(pte, addr, addr + PAGE_SIZE, walk); if (err) break; - addr += PAGE_SIZE; - if (addr == end) + if (addr >= end - PAGE_SIZE) break; + addr += PAGE_SIZE; pte++; } return err;