From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 47047434E27 for ; Mon, 20 Jul 2026 15:48:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784562509; cv=none; b=f22CihwgwpKV+UVzMzw2JB89pV4aSSKysvJeXH1dymzesTQvo7DRH2rTAtA/SXzL0+idgOzCNhywRnYSrHyLTRIYxG242tdXPYWWrX66K35kTYlE3kpvRiC6h/dVa6CQCBQzvmtzQxOEz9COmVdDTQ9dvPnuRvTBoTkJjbj2VhE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784562509; c=relaxed/simple; bh=9SrXS1sbmRLOzrAn7qDAhDWT/7qZmh7/qvkhjQoCTnk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BTTD2PcP5nH27vJJKn6Sfh/w1UPZVPCkB6EB7twMU0dZsF8ONP21ZW4wgdUc8+RaTvJWRW4zUV415zeh01QB9EZ3dWm9CnquieiGwHFE69lUtcPpL3E+7xEnmU98iREIfYKVPG0yvlSKM+ul/23gJNSwGx9+OYReoYGCoXY0/C4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m97wtsbZ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="m97wtsbZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 763531F000E9; Mon, 20 Jul 2026 15:48:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784562508; bh=CvmH3t6cqqMNa2xdCW7Cdmcld9x/hpRFW+Yc11G5jJ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=m97wtsbZrWJKZKsaOjhXK1z4UXxXCAGEkSmQZLpXf7CXjOnczt6DGct2ZdNceIVb2 6p+1hlEaW7W5EZZLWpXHXwICesl2wf6DSsc41+BYGWjIFWO16N9bp1BVbXV1NJqZWK Hn8V5XE7SF4vkje7aQxUoS/AyqPMqjW9wv3NVarle4bvQxoCMz1qBNplr7goxN7AL3 3bpuIA3A/YCiQD8VB+TevsL/QS4G917csgSyL+LA0mvAsz4VmUHq6unc4CAG7McajL k3O2uXuW22diuPECrbqme0BX9nhYGUDyrOZZfz0p0hlbMzHBoHXHVftR3WmEbxtEL4 vhFiF/QJeQdew== From: Sasha Levin To: stable@vger.kernel.org Cc: Neill Kapron , stable , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.15.y] usb: gadget: f_fs: Tie read_buffer lifetime to ffs_epfile Date: Mon, 20 Jul 2026 11:48:25 -0400 Message-ID: <20260720154825.2322611-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026071426-halogen-shrubbery-b87a@gregkh> References: <2026071426-halogen-shrubbery-b87a@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Neill Kapron [ Upstream commit 8bdcf96eb135aebacac319667f87db034fb38406 ] Currently, ffs_epfile_release unconditionally frees the endpoint's read_buffer when a file descriptor is closed. If userspace explicitly opens the endpoint multiple times and closes one, the read_buffer is destroyed. This can lead to silent data loss if other file descriptors are still actively reading from the endpoint. By tying the lifetime of the read_buffer to the ffs_epfile structure itself (which is destroyed when the functionfs instance is torn down in ffs_epfiles_destroy), we eliminate the brittle dependency on open/release calls while correctly matching the conceptual lifetime of unread data on the hardware endpoint. Fixes: 9353afbbfa7b ("usb: gadget: f_fs: buffer data from ‘oversized’ OUT requests") Cc: stable Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260619040609.4010746-3-nkapron@google.com Signed-off-by: Greg Kroah-Hartman [ adjusted context in ffs_epfiles_destroy() since 6.12 lacks the simple_remove_by_name() rework and still uses dentry-based cleanup ] Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_fs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 6efa8ac71b1a08..bfee2eece27cd5 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1291,7 +1291,6 @@ ffs_epfile_release(struct inode *inode, struct file *file) ENTER(); - __ffs_epfile_read_buffer_free(epfile); ffs_data_closed(epfile->ffs); return 0; @@ -1955,6 +1954,7 @@ static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count) for (; count; --count, ++epfile) { BUG_ON(mutex_is_locked(&epfile->mutex)); + __ffs_epfile_read_buffer_free(epfile); if (epfile->dentry) { d_delete(epfile->dentry); dput(epfile->dentry); -- 2.53.0