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 C3B51341ABD; Tue, 26 Aug 2025 14:01:30 +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=1756216890; cv=none; b=Z5DMJ8q+2sQuu0SPWy0lFil9h4BSjG4Qor2qEoWHjfvZh7ArL+eCEpcc4cDjFXPH5x4OwEyxVL53Y8+qjeVAmmeqQGnCfCHm3ktQfPlTCmxnQzsRH5QtOjlXpLFfg7lDzFHG7wK5Dl3PpJwbcWgyDEW/W3glCvSc29kf09b4rhw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756216890; c=relaxed/simple; bh=vbN+5pIbRHgtb02kvSv7sMYAhSRjh2rWQTo9AOrUJBE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CF9/n88m5S19L37gzO7Yp8ECrYBY/f9vtVC5ocxx7yl+MHQYdXlAVPcqKQH4p06IYEash2DCFHZfgFdxHezoVWazZxESPEKIGVVGBmwNpf04u59v6k3n2YoPtIYi4+v2T8OMFVDO5RhwBV8WoQemZE1ePoQwl1JLKlun1SP8Yvc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QN+hnYqn; 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="QN+hnYqn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CB1DC4CEF1; Tue, 26 Aug 2025 14:01:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756216890; bh=vbN+5pIbRHgtb02kvSv7sMYAhSRjh2rWQTo9AOrUJBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QN+hnYqnwZZAhaQxTdtSy2sI+nTz04OfcKRXbJjGE0JrWq4CCfcybLO0EtFuirFAr w2wkJQkRXe3f4bLSUubqsQeKBkHChDI6dDrfQOfOidldnfRsLf4UU/j+PLPDyp+KE3 COyEoAdaPOnsYC0dvyhWNmJ/gdKK/rdzi+xoZA/E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Abbott , stable Subject: [PATCH 5.15 582/644] comedi: Make insn_rw_emulate_bits() do insn->n samples Date: Tue, 26 Aug 2025 13:11:13 +0200 Message-ID: <20250826111000.955028874@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110946.507083938@linuxfoundation.org> References: <20250826110946.507083938@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 5.15-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,