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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id d134sm4917395qkc.42.2019.12.05.05.15.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 05 Dec 2019 05:15:02 -0800 (PST) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH v15 00/23] Generic page walk and ptdump Date: Thu, 5 Dec 2019 08:15:02 -0500 Message-Id: References: <20191204163235.GA1597@arm.com> Cc: David Hildenbrand , Andrew Morton , Linux-MM , Mark Rutland , the arch/x86 maintainers , Arnd Bergmann , Ard Biesheuvel , Peter Zijlstra , Catalin Marinas , Dave Hansen , "linux-kernel@vger.kernel.org" , =?utf-8?Q?J=C3=A9r=C3=B4me_Glisse?= , Ingo Molnar , Borislav Petkov , Andy Lutomirski , "H. Peter Anvin" , James Morse , Thomas Gleixner , Will Deacon , "linux-arm-kernel@lists.infradead.org" , "Liang, Kan" , Thomas Hellstrom In-Reply-To: <20191204163235.GA1597@arm.com> To: Steven Price X-Mailer: iPhone Mail (17B111) 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: > On Dec 4, 2019, at 11:32 AM, Steven Price wrote: >=20 > I've bisected this problem and it's a merge conflict with: >=20 > ace88f1018b8 ("mm: pagewalk: Take the pagetable lock in walk_pte_range()")= Sigh, how does that commit end up merging in the mainline without going thro= ugh Andrew=E2=80=99s tree and missed all the linux-next testing? It was merg= ed into the mainline Oct 4th? > Reverting that commit "fixes" the problem. That commit adds a call to > pte_offset_map_lock(), however that isn't necessarily safe when > considering an "unusual" mapping in the kernel. Combined with my patch > set this leads to the BUG when walking the kernel's page tables. >=20 > At this stage I think it's best if Andrew drops my series and I'll try > to rework it on top -rc1 fixing up this conflict and the other x86 > 32-bit issue that has cropped up.