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As per @KanjiMonster comment: st1202_dt_init() calls devm_led_classdev_register_ext() before the internal data structures are properly setup, so the leds become visible to user space while being partially initialized, leading to a window where trying to access them causes a NULL pointer access. Move devm_led_classdev_register_ext() to the last thing to happen during initialization. Signed-off-by: Manuel Fombuena <fombuena@outlook.com> Link: https://github.com/openwrt/openwrt/pull/17543 Signed-off-by: Robert Marko <robimarko@gmail.com>
71 lines
2.4 KiB
Diff
71 lines
2.4 KiB
Diff
From e3da313ebcace17f1227566fe1b0d0c3883061f9 Mon Sep 17 00:00:00 2001
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From: Manuel Fombuena <fombuena@outlook.com>
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Date: Fri, 17 Jan 2025 12:31:49 +0000
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Subject: [PATCH 1/5] leds: leds-st1202: fix NULL pointer access on race
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condition
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st1202_dt_init() calls devm_led_classdev_register_ext() before the
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internal data structures are properly setup, so the leds become visible
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to user space while being partially initialized, leading to a window
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where trying to access them causes a NULL pointer access.
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This change moves devm_led_classdev_register_ext() to the last thing to
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happen during initialization to eliminate it.
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Signed-off-by: Manuel Fombuena <fombuena@outlook.com>
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---
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drivers/leds/leds-st1202.c | 21 ++++++++++-----------
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1 file changed, 10 insertions(+), 11 deletions(-)
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--- a/drivers/leds/leds-st1202.c
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+++ b/drivers/leds/leds-st1202.c
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@@ -261,8 +261,6 @@ static int st1202_dt_init(struct st1202_
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int err, reg;
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for_each_available_child_of_node_scoped(dev_of_node(dev), child) {
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- struct led_init_data init_data = {};
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-
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err = of_property_read_u32(child, "reg", ®);
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if (err)
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return dev_err_probe(dev, err, "Invalid register\n");
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@@ -276,15 +274,6 @@ static int st1202_dt_init(struct st1202_
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led->led_cdev.pattern_set = st1202_led_pattern_set;
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led->led_cdev.pattern_clear = st1202_led_pattern_clear;
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led->led_cdev.default_trigger = "pattern";
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-
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- init_data.fwnode = led->fwnode;
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- init_data.devicename = "st1202";
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- init_data.default_label = ":";
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-
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- err = devm_led_classdev_register_ext(dev, &led->led_cdev, &init_data);
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- if (err < 0)
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- return dev_err_probe(dev, err, "Failed to register LED class device\n");
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-
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led->led_cdev.brightness_set = st1202_brightness_set;
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led->led_cdev.brightness_get = st1202_brightness_get;
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}
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@@ -368,6 +357,7 @@ static int st1202_probe(struct i2c_clien
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return ret;
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for (int i = 0; i < ST1202_MAX_LEDS; i++) {
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+ struct led_init_data init_data = {};
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led = &chip->leds[i];
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led->chip = chip;
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led->led_num = i;
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@@ -384,6 +374,15 @@ static int st1202_probe(struct i2c_clien
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if (ret < 0)
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return dev_err_probe(&client->dev, ret,
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"Failed to clear LED pattern\n");
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+
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+ init_data.fwnode = led->fwnode;
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+ init_data.devicename = "st1202";
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+ init_data.default_label = ":";
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+
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+ ret = devm_led_classdev_register_ext(&client->dev, &led->led_cdev, &init_data);
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+ if (ret < 0)
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+ return dev_err_probe(&client->dev, ret,
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+ "Failed to register LED class device\n");
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}
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return 0;
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