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Wed, 25 Feb 2026 12:24:35 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 25 Feb 2026 13:24:43 +0100 (CET) Date: Wed, 25 Feb 2026 13:24:34 +0100 From: Oleg Nesterov To: Pavel Tikhomirov Cc: Christian Brauner , Shuah Khan , Kees Cook , Andrew Morton , David Hildenbrand , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Jan Kara , Aleksa Sarai , Andrei Vagin , Kirill Tkhai , Alexander Mikhalitsyn , Adrian Reber , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v3 1/4] pid_namespace: avoid optimization of accesses to ->child_reaper Message-ID: References: <20260224164852.306583-1-ptikhomirov@virtuozzo.com> <20260224164852.306583-2-ptikhomirov@virtuozzo.com> MIME-Version: 1.0 In-Reply-To: <20260224164852.306583-2-ptikhomirov@virtuozzo.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Mimecast-MFC-PROC-ID: 3Cum5TR8UO49F66Y7yinx1ZzBST14roZL4G48DvvJpc_1772022284 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Stat-Signature: xcnawcn19aq1rhejw95wiuptjfmcysfj X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 52A2EA0005 X-HE-Tag: 1772022290-31392 X-HE-Meta: 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 Q/SWUJAY ibalZn3yeaCYdzYTj9/h7SlOXaaMchzn8wK8Ast+sQlqldflpBqcPLPwCbPDWYwh4BK4Z0aYXE4MoCtmbonvZmMaoMJAXoWhmLTixYWEiv4XUKeZxQLq8yLeG2CMU2a67/KRYU5TVHDujC/+hfq9lcS7dhI5lKBjvN/56Y/AwH+ANQx7nSqLq0/PMkrRaWpchqLY6XnZfgDcWrZXisDSMjAE9phZckCrsuBQqmSSebRlGoZ1GKTgc8vjVYAwiJ4y5f08SC6QI+yRS1ufuMP5UNlr1VFpGdzSnK/W5TZ1imsOPQ+NbKf7YiT4tl9wnYSf/4VV7tVhd6iAdUiXypL5zh+DYW2CaUfKXChZcrUHxiD5tqhxie/EM0StYcKe5vflvvcdYontH6P58Vw/CT3D0ukdsv/vbMMoRsRS3Am2LdGNxpOIVZkCjqYh7PJWcYIxbi4fNULlznOeG4aPd4NdiLdFJdE2wZzzFV0POlJq8s0FFqhk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 02/24, Pavel Tikhomirov wrote: > > Also let's add ASSERT_EXCLUSIVE_WRITER before write to identify to KCSAN > that we don't expect any concurrent ->child_reaper modifications, and > those must be detected. Not sure this makes a lot of sense in this case, but I won't argue. > Suggested-by: Oleg Nesterov > Signed-off-by: Pavel Tikhomirov Acked-by: Oleg Nesterov