From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=82.195.75.108 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793094538; b=myDUF2WWQ9q1/FCV/gl8fKvriBTgn4IGNwoF58QA3qY+MYGcPq/NJgkHQ5ies9HVb8Pu yAgKg3ciVULeYjiP1D6uuuDs2LF1V5aSE3dZib6+2w++wcYWZc8OwS0eBZCK8caf7S+tT pJhoIOx9LtGjBw6ygOFTb/gTUeNZG0SaLXBqX/ebZ6e4jRd9lBl4zhG10r+khE+v1LoGn iJ3VEpSfFGGJCI55s9tBwWE5UUc8wkoppe1dmksuM8U+pGPVEFxuXVK5gY27NznH+/cdo X3/5b2AfIVwVJ63dzwtVhKvSU+VtK8pz+nYLzsFBZHKQenL7iSpo/chK1seBKX4PC6Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793094538; h=DMARC-Filter:DKIM-Signature:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To:X-Debian-User; bh=JLf77SLTj5PHtO6sovwzG3G85OtIBR6cqVrzZiXyUwE=; b=YY2ZXvBqBEYfOIuuXOBPqfw9dVx9DbkKD4DJj5OmoIidnEWLyFXcxFfen7zkAeD7OLY0 l2bPsEGDAT1SP2xFpgYM5qxjjQoAtzEMeMlEO0DRn7nVOwluTjoNjuVQEJeMzI3FbSVaC KgFBDAdReG3bP/qoIGivwAHW6bNhk9ry8L9HVlaDFLIqcUGJkDWGnVV9vFoYvfC4S1PzB /8inNbOXc4mb84z41gQSg1s0/D/W4veyqk6jkMtCQef70HOfUQ6N6cjk7Hh4h3hPgoulN YvExLwpmQuS+IvHJJHdOoiA9x8e+b7Qkqgs+u/ibg5KgCVVkxwkVG46v8AJRcDxSD0g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass header.d=debian.org header.i=@debian.org header.a=rsa-sha256 header.s=smtpauto.stravinsky header.b="bCK718n/"; arc=none smtp.remote-ip=82.195.75.108 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C214606A31A; Tue, 27 Oct 2026 09:48:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 8C214606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=debian.org header.i=@debian.org header.a=rsa-sha256 header.s=smtpauto.stravinsky header.b=bCK718n/ DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=JLf77SLTj5PHtO6sovwzG3G85OtIBR6cqVrzZiXyUwE=; b=bCK718n/ZBne26JsgpPhr+1TeK aOyUPSHVLZDMGh9Aqw2rMPLBT68OMdG9zRiwDF4OIVm5ILVdWQwz5pN/7oyUEPkNfbX+Pb9VtbggO G2K7nQnnIo4ekKp0aiyau3kAJoka5i05wK/WUbZQNagtrvfqQk351pc49JewoWtwYjHmf6J26iYAO IfI7V2giU+ymWCK9hSiEmXyzzpmT1KLFojCL7rTmtJIRBmdAVf/BUBscFYtEbcsh/ek9b8OuAG7uL 4J0v5GsemQ7o5Bth+XiglVXywdEVIIPSY938ukYDP7btoM3p739fw7AifYMpZaxgldNxlw3TLPi2b fe2+ZVrQ==; Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1xLdnU-001Mzo-0T; Tue, 27 Oct 2026 09:48:48 +0000 Date: Tue, 27 Oct 2026 02:48:43 -0700 From: Breno Leitao To: Alexander Viro , Christian Brauner , Jan Kara , Shuah Khan Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, linux-kselftest@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] init: do_mounts: free the ramfs info of the boot rootfs Message-ID: References: <20261016-rootfs-kill-sb-v1-1-7631af3ba35f@debian.org> X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261016-rootfs-kill-sb-v1-1-7631af3ba35f@debian.org> X-Debian-User: leitao On Fri, Oct 16, 2026 at 07:27:58AM -0700, Breno Leitao wrote: > Kmemleak is reporting the following leak in ramfs_init_fs_context: > > unreferenced object 0xffff000080302480 (size 8): > comm "swapper/0", pid 0, jiffies 4294667306 > hex dump (first 8 bytes): > ed 01 00 00 00 00 00 00 ........ > backtrace (crc bea23b04): > __kmalloc_cache_noprof+0x28c/0x5a0 > ramfs_init_fs_context+0x5c/0xf8 > rootfs_init_fs_context+0x30/0x40 > alloc_fs_context+0x4c0/0x6a8 > fs_context_for_mount+0x28/0x40 > vfs_kern_mount+0x40/0x220 > init_mount_tree+0x80/0x440 > mnt_init+0x138/0x170 > vfs_caches_init+0x2c/0x48 > start_kernel+0x350/0x3f8 > > When init pivot_root()s away from a ramfs-backed boot rootfs and > unmounts it, the rootfs superblock is killed with kill_anon_super() and > the struct ramfs_fs_info allocated by ramfs_init_fs_context() is never > freed. > > Kill a ramfs-backed rootfs with ramfs_kill_sb(). A tmpfs-backed one keeps > kill_anon_super(), as shmem frees its info in ->put_super. > > Fixes: 576ee5dfd459 ("fs: add immutable rootfs") > Signed-off-by: Breno Leitao Ping?