From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C10972FAC02; Tue, 26 Aug 2025 11:29:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756207775; cv=none; b=aCyc4bfNgBrUGAx2Fi61o+AaaUvd/EyyKtIfp4shqfbG3gRnY1BqNpVYOITdee1KYg8SvhN9HiEtPjwYggwKPvInuhjXcOhy49nfTwBPb6TCTPbj6a9H0DmUGRZKjD9UiqBSz0w3aLmFQAQVlLqyO5Sx36wZxzgoRvqgZLnXRdI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756207775; c=relaxed/simple; bh=DZL0ZvCuFC5jjLgSJ6UC4p7SwPkpyRmQETh9+VnFa+g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jCAyu2RtqrgpnaZrjxI1Mu1LGEsjnk0Uw8SpU22iohqmd2O1boSM+KAn3huB0GXwjWVZgqpx7d7SE+dBIETCW/Yxt6D+7Xnj/jYEGUuz2kc8e0fVg5j98tW8O+x4x+TJBqeRuLVya4J2FCrE8NIrETYsgHNHCe6LAbLiUAsbNaw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qiY8Fge2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qiY8Fge2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5130DC4CEF1; Tue, 26 Aug 2025 11:29:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756207775; bh=DZL0ZvCuFC5jjLgSJ6UC4p7SwPkpyRmQETh9+VnFa+g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qiY8Fge2wh/iaCh1TmIrkAyC8a5tRnpqzgp2wWIv6dmCpUj0eTsdfje458/6cwB32 VN3ZoQptI4sOqIsPn0VJDnTmo5G0wB3E+/yQLDNAk3Kfe3LsHuU/teZPDNVI0zHK7d gBZmXWVE3sP5vrqA4KcyoQB0R3dYX0YKDzAykJoA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Abbott , stable Subject: [PATCH 6.16 311/457] comedi: Make insn_rw_emulate_bits() do insn->n samples Date: Tue, 26 Aug 2025 13:09:55 +0200 Message-ID: <20250826110945.047154969@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110937.289866482@linuxfoundation.org> References: <20250826110937.289866482@linuxfoundation.org> User-Agent: quilt/0.68 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 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Abbott commit 7afba9221f70d4cbce0f417c558879cba0eb5e66 upstream. The `insn_rw_emulate_bits()` function is used as a default handler for `INSN_READ` instructions for subdevices that have a handler for `INSN_BITS` but not for `INSN_READ`. Similarly, it is used as a default handler for `INSN_WRITE` instructions for subdevices that have a handler for `INSN_BITS` but not for `INSN_WRITE`. It works by emulating the `INSN_READ` or `INSN_WRITE` instruction handling with a constructed `INSN_BITS` instruction. However, `INSN_READ` and `INSN_WRITE` instructions are supposed to be able read or write multiple samples, indicated by the `insn->n` value, but `insn_rw_emulate_bits()` currently only handles a single sample. For `INSN_READ`, the comedi core will copy `insn->n` samples back to user-space. (That triggered KASAN kernel-infoleak errors when `insn->n` was greater than 1, but that is being fixed more generally elsewhere in the comedi core.) Make `insn_rw_emulate_bits()` either handle `insn->n` samples, or return an error, to conform to the general expectation for `INSN_READ` and `INSN_WRITE` handlers. Fixes: ed9eccbe8970 ("Staging: add comedi core") Cc: stable # 5.13+ Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20250725141034.87297-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/comedi/drivers.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) --- a/drivers/comedi/drivers.c +++ b/drivers/comedi/drivers.c @@ -620,11 +620,9 @@ static int insn_rw_emulate_bits(struct c unsigned int chan = CR_CHAN(insn->chanspec); unsigned int base_chan = (chan < 32) ? 0 : chan; unsigned int _data[2]; + unsigned int i; int ret; - if (insn->n == 0) - return 0; - memset(_data, 0, sizeof(_data)); memset(&_insn, 0, sizeof(_insn)); _insn.insn = INSN_BITS; @@ -635,18 +633,21 @@ static int insn_rw_emulate_bits(struct c if (insn->insn == INSN_WRITE) { if (!(s->subdev_flags & SDF_WRITABLE)) return -EINVAL; - _data[0] = 1U << (chan - base_chan); /* mask */ - _data[1] = data[0] ? (1U << (chan - base_chan)) : 0; /* bits */ + _data[0] = 1U << (chan - base_chan); /* mask */ } + for (i = 0; i < insn->n; i++) { + if (insn->insn == INSN_WRITE) + _data[1] = data[i] ? _data[0] : 0; /* bits */ + + ret = s->insn_bits(dev, s, &_insn, _data); + if (ret < 0) + return ret; - ret = s->insn_bits(dev, s, &_insn, _data); - if (ret < 0) - return ret; - - if (insn->insn == INSN_READ) - data[0] = (_data[1] >> (chan - base_chan)) & 1; + if (insn->insn == INSN_READ) + data[i] = (_data[1] >> (chan - base_chan)) & 1; + } - return 1; + return insn->n; } static int __comedi_device_postconfig_async(struct comedi_device *dev,