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Mon, 19 Oct 2026 18:52:45 -0700 (PDT) Received: from Legion5 ([144.39.120.39]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-36632d8b273sm871428eec.15.2026.10.19.18.52.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Oct 2026 18:52:44 -0700 (PDT) From: Grayson Tinker To: Alejandro Colomar Cc: linux-man@vger.kernel.org, Grayson Tinker Subject: [PATCH] man/man5/tmpfs.5: Specify that noswap may not be used within unprivileged user namespaces Date: Mon, 19 Oct 2026 19:51:12 -0600 Message-ID: <20261020015112.127389-1-graysontinker@gmail.com> X-Mailer: git-send-email 2.55.0 X-Mailing-List: linux-man@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Since the tmpfs noswap option was added, the kernel has disallowed its use while within an unprivileged user namespace for security reasons. Document this restriction so users do not believe noswap to be available in every situation. ref. linux.git 01106e140835ff94fdef79d66f166b87b0c89824 ("shmem: restrict noswap option to initial user namespace") Signed-off-by: Grayson Tinker --- man/man5/tmpfs.5 | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/man/man5/tmpfs.5 b/man/man5/tmpfs.5 index 10acbdcfa..a904db2c8 100644 --- a/man/man5/tmpfs.5 +++ b/man/man5/tmpfs.5 @@ -109,6 +109,10 @@ but not a % suffix. Disables swap. Remounts must respect the original settings. By default swap is enabled. +.IP +.\" commit 01106e140835ff94fdef79d66f166b87b0c89824 +.B noswap +is not available while within an unprivileged user namespace. .TP .BR mode =\f[I]mode\f[] Set initial permissions of the root directory. Range-diff: -: --------- > 1: b3b2becca man/man5/tmpfs.5: Specify that noswap may not be used within unprivileged user namespaces -- 2.55.0