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 B55163B6C17; Tue, 21 Jul 2026 22:29:25 +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=1784672966; cv=none; b=tlLzEqWvMdDOHeqBfy8MSaXnCWtCl8CEQeLhuvUw6HHI4g5ZWGLnaEoKPWyHTfcUA+1/W9sgNT9pL+8kElhMmnGgYEZf0Zq/FfoUyVXGj6yLqCfNw1NrsyzgSH4et2S5YeXPchyhKtAgzMhvP4XiJxOj2DSAeEgLMFd39Eeo/Fc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784672966; c=relaxed/simple; bh=1iMSnfdfwMh4yCwxN4sSC7o+ijqYp/LrnoB2WE9xK9A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=n672WcQOp/CQOg/Ddiav0KjgfYivX/+dbOpUTb35FvK8nqyQafDVrQkV3AsAoOLDGs//V/aoEBr/1WPC2khk/azPX5c5no6J8G7EIZX/FeDvbucxHNiBfsVIYXu1NU7Cr2yWlOXOPmYM9AXBGrHrbBxUfGgmoaIPyi6weJiAlY0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=haL7yuwo; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="haL7yuwo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2745B1F000E9; Tue, 21 Jul 2026 22:29:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784672965; bh=wq4iLn1d6qCVJd07OKJwSLAx7lTtPvwjY0pfB4GXKYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=haL7yuwom7Zfc9y+wQCm18W+BkQudUE4wDsExiarJY2f5+SAnrimLsoKrVEMpLxwH HX6lCPU4VXIWF9gRFz8G+SlRPlC9IRMnKd7i87H44RNrmDiqkcMrFrPNTSo1n5X8HV NdOMggagV5Cmr9NpwQj8/d0Yvkf5EA9KieTndPaE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Neill Kapron , Sasha Levin Subject: [PATCH 5.15 825/843] usb: gadget: f_fs: Tie read_buffer lifetime to ffs_epfile Date: Tue, 21 Jul 2026 17:27:40 +0200 Message-ID: <20260721152424.635659922@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1292,7 +1292,6 @@ ffs_epfile_release(struct inode *inode, ENTER(); - __ffs_epfile_read_buffer_free(epfile); ffs_data_closed(epfile->ffs); return 0; @@ -1957,6 +1956,7 @@ static void ffs_epfiles_destroy(struct f 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);