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b=NLUEIV05TiKc0C/byycgiDauYslTGWVbc+nJ1MUD9VUnqU25rGdqejVNIqBf3pKFJ 5vpamPJuuFs302pY7sKIbWnzJH32VnHKvul5fJk3jKvVr7Tc+RFWXj9/iGc6IbDVjl jCkFhVX+S5jF61sHSBBZOd0TuT3bqST8wCP0BMs9ud2VQgDsc4+ALG3BZb2tvRbwc8 rD9T9C5cZmKTsNXBA80mNGwvnvY3UmL55JJqvuEJmNzO1rvzvBkuoryvD8WVHSieJo 2LInadbEVFU7SMGahlhm0imyS859rWt1Y/OvYWDYXJH3pd+0RiHs+LPs5X/QFonpeZ Ws1Um62uUwtBg== From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH 3/6] fs/namespace: Add vfs_open_detached_mount() Reply-To: sashiko-reviews@lists.linux.dev To: "Andrew Morton" , "Samiullah Khawaja" , "Alexander Graf" , "Mike Rapoport" , "Lorenzo Stoakes" , "Baolin Wang" , "Pratyush Yadav" , "David Hildenbrand" , "Pasha Tatashin" , "Hugh Dickins" , "David Matlack" Cc: kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org In-Reply-To: <20260923224408.3745689-4-pratyush@kernel.org> References: <20260923224408.3745689-1-pratyush@kernel.org> <20260923224408.3745689-4-pratyush@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 23 Sep 2026 23:01:52 +0000 Message-Id: <20260923230152.8160E1F000FF@smtp.kernel.org> X-Rspamd-Queue-Id: ACDDD40014 X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: s9831u7ujoy8murcjx4arhj1qonixkd5 X-HE-Tag: 1790204514-853424 X-HE-Meta: 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 iULF0vz0 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] fs: mount reference leak in vfs_open_detached_mount() error path -- commit 7bbd41a97d183f30490f0856f394037fd1846a6f Author: Pratyush Yadav (Google) fs/namespace: Add vfs_open_detached_mount() This commit factors out the creation of an anonymous mount namespace and an O_PATH file for a detached mount into a new helper, vfs_open_detached_mount. This allows in-kernel mount creators to hand a detached mount file to userspace, similar to what fsmount does. > diff --git a/fs/namespace.c b/fs/namespace.c > index 1ecd96c918b33..5e7ba2b61dd9a 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c [ ... ] > +/** > + * vfs_open_detached_mount - Publish a new mount as a detached mount fil= e. > + * @mnt: The mount to publish. Must not be attached to a mount namespace= . The > + * caller's reference is consumed on success. [ ... ] > + * Return: the new file, or an ERR_PTR. On failure the caller's referenc= e to > + * @mnt is dropped, as the mount cannot be published. > + */ > +struct file *vfs_open_detached_mount(struct vfsmount *mnt) > +{ > + struct path path __free(path_put) =3D {}; > + struct mnt_namespace *ns; > + struct file *file; > + > + if (WARN_ON_ONCE(real_mount(mnt)->mnt_ns)) > + return ERR_PTR(-EINVAL); [Severity: Medium] Does this error path leak the vfsmount reference? The function documentation explicitly guarantees that on failure, the caller's reference to mnt is dropped. If a caller inadvertently passes a mount already attached to a mount namespace, this WARN_ON_ONCE condition evaluates to true and the function returns an error without dropping the reference. For comparison, the error path immediately below for alloc_mnt_ns failure correctly calls mntput(mnt) before returning. > + > + ns =3D alloc_mnt_ns(current->nsproxy->mnt_ns->user_ns, true); > + if (IS_ERR(ns)) { > + mntput(mnt); > + return ERR_CAST(ns); > + } [ ... ] --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260923224408.3745= 689-1-pratyush@kernel.org?part=3D3