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[109.81.20.115]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488fb762f56sm10333105e9.15.2026.04.17.00.04.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Apr 2026 00:04:32 -0700 (PDT) Date: Fri, 17 Apr 2026 09:04:31 +0200 From: Michal Hocko To: Minchan Kim Cc: Christian Brauner , akpm@linux-foundation.org, david@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, surenb@google.com, timmurray@google.com Subject: Re: [RFC 3/3] mm: process_mrelease: introduce PROCESS_MRELEASE_REAP_KILL flag Message-ID: References: <20260413223948.556351-1-minchan@kernel.org> <20260413223948.556351-4-minchan@kernel.org> <20260416-planktont-abwinken-b9499483b939@brauner> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: CE85914000B X-Stat-Signature: qqt8gk9o8ai3hf6wrqd1dtai9tw1dq45 X-Rspam-User: X-HE-Tag: 1776409474-530363 X-HE-Meta: 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 nCs3J3Sz ukXz0/3KxeyPjZHitWZofSNBCQdEMysJLmYvn3lhBnHpwn5AZsAbsPV3LHgtVug+lm2UE3T8BCmXtZP3qjw8DplYDyGyOlPRV+2IVF1T40V1k6RMyGXsBjAQKxLLxlGONc7GPM7Pv0AUaIWff3iAV71SXifxpbRfBJ7zo6dv0Z8xFiQLc0HyKBDzKm0WFWtwyUrjVQyqZo4FdfSu9lU3VrA0jY3e7w3J/XtFXIiWplY4elhKnnBX75SOsVb4pSGUaGF3kqdys58IQUZNhXp6QjTa8ZfQxEyQH/S5XHCuJwbiMQM6aboOvme2bAQtyS12N4dPixAOPkNtvx5XQyDslZ/VyUgqZOHUM11UAwnWxUeuN0Xkl9iyHqnaMqlr8qBkV4Vn2FPliwFknbG5wGCrFq1H7BJybBHtqqXbfWFJogFzIcTY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu 16-04-26 23:30:09, Minchan Kim wrote: > If I send the SIGKILL first to satisfy the process_mrelease() requirement, > we immediately run into the scheduling race condition where the victim can > enter the exit path before the reaper can set the flag. Why don't you just grab the mm before you send the signal and then continue with reaping? You just want to avoid a race where the victim manages to process fatal signal, start its exit path and mrelease path losing that race so you rely on the exit path, right? -- Michal Hocko SUSE Labs