From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-69.mta1.migadu.com [95.215.58.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 01DD336B903 for ; Fri, 28 Aug 2026 09:17:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787908629; cv=none; b=U6ce/0S/gPv+El5FuYk4O2rSZYuXUskHw4PgyWFzcBtKFVMfHYa01BTbm4rH5YIg1rWcerKrqcFi6urRWuHmASgCXvuHTSg1BkSWOKmo/b8CvV+MqFp0JGr2epACy58eOjAazdI/wURjfcwiNneEkJ+dcJ6trrRveMVQhNnEq78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787908629; c=relaxed/simple; bh=9I5a0QMwrg3+lfQBpS9YxYe1Q1fOoYtS9mP3Zj5tR1w=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ART0u+0rM+TWvjUXPLmoBxpC1GGfaIFyP9fjfv4UB4+8wRO4Ehz+XQNqwXWDBdAYEwHuvE6rZUHF65FBY3vZlADU1tLJyME6VQiIziBL7wVhbRtrwNeWqYc7V5sFLX7/0sfkdDSE5pe6UlfqIsNYZ2uUofjf7PxbdN/hQ1uoO3w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=OPswyrSV; arc=none smtp.client-ip=95.215.58.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="OPswyrSV" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=9I5a0QMwrg3+lfQBpS9YxYe1Q1fOoYtS9mP3Zj5tR1w=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787908626; v=1; x=1788513426; b=OPswyrSV23p1kQx+0AD2+pSmu7AxIYDgi/rQLu9HWxvUR+UPJEI+j6R4jLprB4VIb5IsWYha ZI/VaBKC/N3Q/OAPcMH7RVHifdI8dRm3KsX8Mf3Qtdl9vJ+24JoT0ZMYDYNnH9u55dlz7CVh0Pz G/noVuvkAB2WVIbZBptL0iLE= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id f0b5d2dde67889ac; Fri, 28 Aug 2026 09:17:06 +0000 X-Mizu-Trace-ID: f0b5d2dde67889ac X-Migadu-Flow: FLOW_OUT From: Tao Cui To: brauner@kernel.org Cc: jack@suse.cz, kees@kernel.org, cyphar@cyphar.com, containers@vger.kernel.org, linux-kernel@vger.kernel.org, cuitao@kylinos.cn, cui.tao@linux.dev Subject: [PATCH 0/2] userns: clean up dead code on error paths Date: Fri, 28 Aug 2026 17:16:57 +0800 Message-ID: <20260828091659.358700-1-cui.tao@linux.dev> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tao Cui Two small cleanups on the create_user_ns() and map_write() error paths. Both remove code that provably cannot have an effect; no behavior change. user_namespace.c:164-167: the key_put() at fail_keyring has been dead since it was copy-pasted from free_user_ns() in 2016 (dbec28460a89); persistent_keyring_register is only ever assigned lazily from key_get_persistent(), long after create_user_ns(). user_namespace.c:1110-1112: the map clearing at the out: label of map_write() only ever zeroes an already-zero map; the destination map is untouched on every error path, and a second write to a mapped namespace is rejected before parsing. Compile-tested and A/B-tested on next-20260827: identical behavior on vanilla and patched kernels for single-write map failures, recovery writes and 300 rounds of userns create/destroy. Tao Cui (2): userns: remove dead key_put() on the create_user_ns() error path userns: don't clear the install target map on map_write() failure kernel/user_namespace.c | 6 ------ 1 file changed, 6 deletions(-) -- 2.43.0