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 79F3719D8BC; Sat, 12 Sep 2026 10:28:30 +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=1789208911; cv=none; b=BG/ZOnlwin/FysUEfQvR8fPXZnOOINx+0HshlrmdSP0tG7q/ZZhiAfPQD+r2oyXuOFLfF6wGu85K4XBisrrJIGYK+womP1x9av4dOTNTbsJNUGYITokq7D6IGSocIZvRNc8oFM265lDAq0go4aSKA0ZX4Fqj6+5YMbZ/cnXJ518= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789208911; c=relaxed/simple; bh=qLwrkUv8O8rCMm+LQyT+kQn7sfUMtpPKVfpOZQi2b/E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GNwERCbJwzKIj8SxcfINwUD/SoxPsBMJmfAOe03ep9pKCsLV7iH2VWR6NbpSqE8yeS1OMYbHWzMw/4tCBuFDfynJoeSoqVKBitn2ygkuxFJ8x7D0yJT2EVVifAa5qgtjtbBm/xaGgJV8b3SJuJZgBm0ZowKo30udMAiLQCtLjxE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EmJ2QMeA; 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="EmJ2QMeA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A10C71F00893; Sat, 12 Sep 2026 10:28:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789208910; bh=06mav7nhtlcQCkiptUycMOJLkLTrutztdiijt6Nkycg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EmJ2QMeAyx+XeDi2UTTSYuilYo5srtj47FsLrWtjNSVQsL02Tf8iKnYqnsTZIBtoG l62hX0bvXLn6GsI5blHVfSbi+4rBbcMia7uSsM61+U6ihNkYwGWV2AyF5Xpl+tvKi5 +GNQV9VLllETX0+VHrlQ3hSmzrCXqrnnB7NmK/Xg= 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 6.18 0714/1518] i3c: dw: avoid shift-out-of-bounds when DAA assigns no devices Date: Sat, 12 Sep 2026 08:48:03 +0200 Message-ID: <20260912065639.586791108@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065623.398859879@linuxfoundation.org> References: <20260912065623.398859879@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 6.18-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 675c257ebe2c2..4a4fae96be370 100644 --- a/drivers/i3c/master/dw-i3c-master.c +++ b/drivers/i3c/master/dw-i3c-master.c @@ -883,7 +883,15 @@ 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