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 2F19C38656D; Sat, 12 Sep 2026 18:55:16 +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=1789239318; cv=none; b=nw8zCEcUgzE9rPMbaclQrQ8liLRQupoMZIS6NG75yRwiPpXaS4RPQkVgMZvgv4zbotsXAiGmkwbrKzM8YfmjstVKwA9hnX/ViRelY/LpVsRRBiPOCpRJDT6uSD+27NeLGufK2g281t5HuAH+5rOiPMsKWVzMGH2uQsS5ln90yK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789239318; c=relaxed/simple; bh=Lxh457NPu/m7SThH2lQP3xY1Gt9W3OrWHWoosLbUrxk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Mim3SGfcRySFDSznwuo5WXFzsfrf3eks2+i4o69PJ4UEM2Aafv2f0smiccInzhy0rnxc/bWjeOkuFdpQC9JtOf7ni7XkSQ4p94phKmQkO3AIcbSnrv7/AYmca+ecsHP2GTyz77GtkPqMaKR+JyNVRoJs7+L+cAZjPf1+5rIh/2E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DP91D++4; 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="DP91D++4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A36D1F000FF; Sat, 12 Sep 2026 18:55:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789239316; bh=IeyaNkCqbU7ytOfrcrky8OZejQXDNf+bBlswfgrOgRw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DP91D++4X91ws34QO4fONi+heAI2/+ppEDV4UDly5OkwPILb3j/WB/sQxnSd+4Iie UhhkU5Gta476t1sAnjxpQ64qADgmQWvWBvUmVcyqDLDRY5mEYAwXoNmv+m+qO9dQMZ uTGXK/vKnvtWMsdCSGbr+kWpCEZW4nByKfhJjrVk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jakub Kicinski , Frank Li , Alexandre Belloni , Sasha Levin Subject: [PATCH 5.15 641/935] i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices Date: Sat, 12 Sep 2026 09:01:11 +0200 Message-ID: <20260912065541.544075914@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065526.833703348@linuxfoundation.org> References: <20260912065526.833703348@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-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jakub Kicinski [ Upstream commit 038cf48b3170af26a70bf2dee4f8c3ac910f5176 ] On an empty bus ENTDAA assigns nothing, so cmd->rx_len (the count of addresses left unassigned) equals master->maxdevs. The GENMASK() index master->maxdevs - cmd->rx_len - 1 then becomes -1, which trips up UBSAN. This happens every time on boot on a Gigabyte/AMD server: UBSAN: shift-out-of-bounds in drivers/i3c/master/dw-i3c-master.c:905:12 shift exponent 64 is too large for 64-bit type 'long unsigned int' CPU: 7 UID: 0 PID: 963 Comm: (udev-worker) Not tainted 7.0.11-200.fc44.x86_64 #1 PREEMPT(lazy) Hardware name: Giga Computing E163-Z34-AAH1-000/MZ33-DC1-000, BIOS R32_F45 04/01/2026 Call Trace: dump_stack_lvl+0x5d/0x80 ubsan_epilogue+0x5/0x2b __ubsan_handle_shift_out_of_bounds.cold+0xd7/0x1ab dw_i3c_master_daa.cold+0x1b/0x96 [dw_i3c_master] i3c_master_do_daa_ext.part.0+0x3e/0xf0 [i3c] Skip the mask when no new device was assigned. Fixes: 1dd728f5d4d4 ("i3c: master: Add driver for Synopsys DesignWare IP") Signed-off-by: Jakub Kicinski Reviewed-by: Frank Li Link: https://patch.msgid.link/20260630172904.2662160-1-kuba@kernel.org Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin --- drivers/i3c/master/dw-i3c-master.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c index 51a8608203de7..11b1cec6398f3 100644 --- a/drivers/i3c/master/dw-i3c-master.c +++ b/drivers/i3c/master/dw-i3c-master.c @@ -810,7 +810,15 @@ static int dw_i3c_master_daa(struct i3c_master_controller *m) if (!wait_for_completion_timeout(&xfer->comp, XFER_TIMEOUT)) dw_i3c_master_dequeue_xfer(master, xfer); - newdevs = GENMASK(master->maxdevs - cmd->rx_len - 1, 0); + /* + * cmd->rx_len holds the number of addresses ENTDAA left unassigned. + * On an empty bus rx_len == maxdevs, so avoid GENMASK(-1, 0). + */ + if (cmd->rx_len >= master->maxdevs) + newdevs = 0; + else + newdevs = GENMASK(master->maxdevs - cmd->rx_len - 1, 0); + newdevs &= ~olddevs; for (pos = 0; pos < master->maxdevs; pos++) { -- 2.53.0