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Message-ID: <42be0934-2e97-4d02-98df-b5a03195e8ae@quicinc.com>
Date: Thu, 29 May 2025 11:11:33 +0800
From: Fenglin Wu <fenglin.wu@....qualcomm.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
Lee Jones <lee@...nel.org>, Pavel Machek <pavel@...nel.org>,
linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: stable@...r.kernel.org
Subject: Re: [PATCH] leds: flash: leds-qcom-flash: Fix registry access after
re-bind
On 5/29/2025 3:44 AM, Krzysztof Kozlowski wrote:
> Driver in probe() updates each of 'reg_field' with 'reg_base':
>
> for (i = 0; i < REG_MAX_COUNT; i++)
> regs[i].reg += reg_base;
>
> 'reg_field' array (under variable 'regs' above) is statically allocated,
> this each re-bind would add another 'reg_base' leading to bogus
> register addresses. Constify the local 'reg_field' array and duplicate
> it in probe to solve this.
>
> Fixes: 96a2e242a5dc ("leds: flash: Add driver to support flash LED module in QCOM PMICs")
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>
> ---
>
> This is a nice example why constifying static memory is useful.
Thanks for fixing it!
> ---
> drivers/leds/flash/leds-qcom-flash.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/leds/flash/leds-qcom-flash.c b/drivers/leds/flash/leds-qcom-flash.c
> index b4c19be51c4d..b8a48c15d797 100644
> --- a/drivers/leds/flash/leds-qcom-flash.c
> +++ b/drivers/leds/flash/leds-qcom-flash.c
> @@ -117,7 +117,7 @@ enum {
> REG_MAX_COUNT,
> };
>
> -static struct reg_field mvflash_3ch_regs[REG_MAX_COUNT] = {
> +static const struct reg_field mvflash_3ch_regs[REG_MAX_COUNT] = {
> REG_FIELD(0x08, 0, 7), /* status1 */
> REG_FIELD(0x09, 0, 7), /* status2 */
> REG_FIELD(0x0a, 0, 7), /* status3 */
> @@ -132,7 +132,7 @@ static struct reg_field mvflash_3ch_regs[REG_MAX_COUNT] = {
> REG_FIELD(0x58, 0, 2), /* therm_thrsh3 */
> };
>
> -static struct reg_field mvflash_4ch_regs[REG_MAX_COUNT] = {
> +static const struct reg_field mvflash_4ch_regs[REG_MAX_COUNT] = {
> REG_FIELD(0x06, 0, 7), /* status1 */
> REG_FIELD(0x07, 0, 6), /* status2 */
> REG_FIELD(0x09, 0, 7), /* status3 */
> @@ -854,11 +854,17 @@ static int qcom_flash_led_probe(struct platform_device *pdev)
> if (val == FLASH_SUBTYPE_3CH_PM8150_VAL || val == FLASH_SUBTYPE_3CH_PMI8998_VAL) {
> flash_data->hw_type = QCOM_MVFLASH_3CH;
> flash_data->max_channels = 3;
> - regs = mvflash_3ch_regs;
> + regs = devm_kmemdup(dev, mvflash_3ch_regs, sizeof(mvflash_3ch_regs),
> + GFP_KERNEL);
> + if (!regs)
> + return -ENOMEM;
> } else if (val == FLASH_SUBTYPE_4CH_VAL) {
> flash_data->hw_type = QCOM_MVFLASH_4CH;
> flash_data->max_channels = 4;
> - regs = mvflash_4ch_regs;
> + regs = devm_kmemdup(dev, mvflash_4ch_regs, sizeof(mvflash_3ch_regs),
Minor: sizeof(mvflash_4ch_regs)
> + GFP_KERNEL);
> + if (!regs)
> + return -ENOMEM;
>
> rc = regmap_read(regmap, reg_base + FLASH_REVISION_REG, &val);
> if (rc < 0) {
> @@ -880,6 +886,7 @@ static int qcom_flash_led_probe(struct platform_device *pdev)
> dev_err(dev, "Failed to allocate regmap field, rc=%d\n", rc);
> return rc;
> }
> + devm_kfree(dev, regs); /* devm_regmap_field_bulk_alloc() makes copies */
>
> platform_set_drvdata(pdev, flash_data);
> mutex_init(&flash_data->lock);
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