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[24.205.208.113]) by smtp.gmail.com with ESMTPSA id i1-20020a375401000000b0069fc13ce246sm6992189qkb.119.2022.05.09.07.51.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 May 2022 07:51:27 -0700 (PDT) Subject: Re: [PATCH] mm/shmem: initialize folio to NULL To: Matthew Wilcox Cc: hughd@google.com, akpm@linux-foundation.org, nathan@kernel.org, ndesaulniers@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev References: <20220509123116.3169267-1-trix@redhat.com> From: Tom Rix Message-ID: <0f066c75-121e-05f2-41ed-0d029bf70221@redhat.com> Date: Mon, 9 May 2022 07:51:25 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Stat-Signature: 5mkjhkte5o5d1h75c78cf9kozrtutnob X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 31EAEA0093 X-Rspam-User: Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=I1AM7iLZ; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf25.hostedemail.com: domain of trix@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=trix@redhat.com X-HE-Tag: 1652107874-948861 X-Bogosity: Ham, tests=bogofilter, spamicity=0.001838, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 5/9/22 6:59 AM, Matthew Wilcox wrote: > On Mon, May 09, 2022 at 08:31:16AM -0400, Tom Rix wrote: >> The clang build fails with >> mm/shmem.c:1704:7: error: variable 'folio' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] >> if (!page) { >> ^~~~~ >> The error handler for !page jumps to an if-check for an unset folio. >> So initialize folio to NULL. > I appreciate you're trying to help, but the fourth report of a problem > adds more noise than utility. > > https://lore.kernel.org/linux-mm/?q=shmem+folio > > shows emails about this from the cgelbot, Dan Carpenter, SeongJae Park, > Colin King, Nathan Chancellor and Sebastian Siewior. So actually you > were seventh, not fourth. From my point of view, the build has been broken for a week. It would be good if this and the other folio issue was fixed in linux-next soon. Tom >