From: Alexander Stein alexander.stein@ew.tq-group.com
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=...
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[ 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: Alexander Stein alexander.stein@ew.tq-group.com Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Reviewed-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: dinglongwei dinglongwei1@huawei.com --- drivers/i2c/busses/i2c-imx-lpi2c.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c index 678b30e90492..14473c223cfa 100644 --- a/drivers/i2c/busses/i2c-imx-lpi2c.c +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c @@ -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);