Commit cb4a5ba3 authored by Alexander Stein's avatar Alexander Stein Committed by dinglongwei
Browse files

i2c: lpi2c: Avoid calling clk_get_rate during transfer 

stable inclusion
from stable-v6.9.7
commit 2b42e9587a7a9c7b824e0feb92958f258263963e
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IACTBX
CVE: CVE-2024-40965

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2b42e9587a7a9c7b824e0feb92958f258263963e



--------------------------------

[ Upstream commit 4268254a39484fc11ba991ae148bacbe75d9cc0a ]

Instead of repeatedly calling clk_get_rate for each transfer, lock
the clock rate and cache the value.
A deadlock has been observed while adding tlv320aic32x4 audio codec to
the system. When this clock provider adds its clock, the clk mutex is
locked already, it needs to access i2c, which in return needs the mutex
for clk_get_rate as well.

Signed-off-by: default avatarAlexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatardinglongwei <dinglongwei1@huawei.com>
parent 9dca94c1

drivers/i2c/busses/i2c-imx-lpi2c.c

+16 −3
Original line number Diff line number Diff line
@@ -99,6 +99,7 @@ struct lpi2c_imx_struct { 
	__u8			*rx_buf;

	__u8			*tx_buf;

	struct completion	complete;

	unsigned long		rate_per;

	unsigned int		msglen;

	unsigned int		delivered;

	unsigned int		block_data;
@@ -207,9 +208,7 @@ static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx) 


	lpi2c_imx_set_mode(lpi2c_imx);



	clk_rate = clk_get_rate(lpi2c_imx->clks[0].clk);

	if (!clk_rate)

		return -EINVAL;

	clk_rate = lpi2c_imx->rate_per;



	if (lpi2c_imx->mode == HS || lpi2c_imx->mode == ULTRA_FAST)

		filt = 0;
@@ -590,6 +589,20 @@ static int lpi2c_imx_probe(struct platform_device *pdev) 
	if (ret)

		return ret;



	/*

	 * Lock the parent clock rate to avoid getting parent clock upon

	 * each transfer

	 */

	ret = devm_clk_rate_exclusive_get(&pdev->dev, lpi2c_imx->clks[0].clk);

	if (ret)

		return dev_err_probe(&pdev->dev, ret,

				     "can't lock I2C peripheral clock rate\n");



	lpi2c_imx->rate_per = clk_get_rate(lpi2c_imx->clks[0].clk);

	if (!lpi2c_imx->rate_per)

		return dev_err_probe(&pdev->dev, -EINVAL,

				     "can't get I2C peripheral clock rate\n");



	pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);

	pm_runtime_use_autosuspend(&pdev->dev);

	pm_runtime_get_noresume(&pdev->dev);