From: Breno Leitao <leitao@debian.org>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Shuah Khan <shuah@kernel.org>
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
Date: Tue, 27 Oct 2026 02:48:43 -0700 [thread overview]
Message-ID: <auBzcXQw0j4zTvTM@gmail.com> (raw)
In-Reply-To: <20261016-rootfs-kill-sb-v1-1-7631af3ba35f@debian.org>
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 <leitao@debian.org>
Ping?
next prev parent reply other threads:[~2026-10-27 9:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-16 14:27 Breno Leitao
2026-10-27 9:48 ` Breno Leitao [this message]
2026-10-29 9:28 ` Zenghui Yu
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