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Mon, 07 Oct 2024 19:35:14 -0700 (PDT) MIME-Version: 1.0 References: <20241004142504.4379-1-aha310510@gmail.com> <202410071223.t0yF8vP8-lkp@intel.com> <20241007183052.9d87f42e19db5f9777dc8e77@linux-foundation.org> In-Reply-To: <20241007183052.9d87f42e19db5f9777dc8e77@linux-foundation.org> From: Jeongjun Park Date: Tue, 8 Oct 2024 11:35:03 +0900 Message-ID: Subject: Re: [PATCH] mm: swap: prevent possible data-race in __try_to_reclaim_swap To: Andrew Morton Cc: kernel test robot , llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, kasong@tencent.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, syzbot+fa43f1b63e3aa6f66329@syzkaller.appspotmail.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 11EAA100006 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 9wnzkwg3di9aeztitfqi7k9kmdq81fm1 X-HE-Tag: 1728354915-605261 X-HE-Meta: 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 yCI8jQM8 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Andrew Morton wrote: > > On Mon, 7 Oct 2024 13:06:49 +0800 kernel test robot wrote: > > > Hi Jeongjun, > > > > kernel test robot noticed the following build warnings: > > > > [auto build test WARNING on akpm-mm/mm-everything] > > > > url: https://github.com/intel-lab-lkp/linux/commits/Jeongjun-Park/mm-swap-prevent-possible-data-race-in-__try_to_reclaim_swap/20241004-222733 > > base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything > > patch link: https://lore.kernel.org/r/20241004142504.4379-1-aha310510%40gmail.com > > patch subject: [PATCH] mm: swap: prevent possible data-race in __try_to_reclaim_swap > > config: x86_64-kexec (https://download.01.org/0day-ci/archive/20241007/202410071223.t0yF8vP8-lkp@intel.com/config) > > compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff) > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241007/202410071223.t0yF8vP8-lkp@intel.com/reproduce) > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot > > | Closes: https://lore.kernel.org/oe-kbuild-all/202410071223.t0yF8vP8-lkp@intel.com/ > > > > All warnings (new ones prefixed by >>): > > > > >> mm/swapfile.c:203:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > > 203 | if (!folio_trylock(folio)) > > | ^~~~~~~~~~~~~~~~~~~~~ > > mm/swapfile.c:254:9: note: uninitialized use occurs here > > 254 | return ret; > > This warning can't be correct? I think it's correct. Even if folio_trylock fails, the return value should be -nr_pages. Not initializing ret like in the v1 patch goes against the design purpose of the function. So I think it's right to apply the v2 patch that I sent you. Regards, Jeongjun Park