From patchwork Wed Apr 12 21:58:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 673728 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83558C77B73 for ; Wed, 12 Apr 2023 21:59:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229764AbjDLV7v (ORCPT ); Wed, 12 Apr 2023 17:59:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229713AbjDLV7u (ORCPT ); Wed, 12 Apr 2023 17:59:50 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DE402D44 for ; Wed, 12 Apr 2023 14:59:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681336746; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AhetMPUccSBGno+6g7p6C7Kms99tBheeFDpdLpTBUok=; b=Qm4/s5A6GMOpQ/sliO2+pp7gGpJiUrJ2ZzALoQ3UmklLdJLXirAlZcRaZ2OGfIgROQOGMy xICl0lTIHj2zaL9Cg7WZBB3NH2Ate8MxagbJD8HGhBn2sWiyO3bgGgsZuVijvhoax+5+Qk K4cG7u9oj3Qm4zR3CKFg4iO4ftWgOAQ= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-29-blTWuD84M3CT3qKgxfMdhQ-1; Wed, 12 Apr 2023 17:59:03 -0400 X-MC-Unique: blTWuD84M3CT3qKgxfMdhQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E2386380673E; Wed, 12 Apr 2023 21:59:02 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.192.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id 17C1B1121320; Wed, 12 Apr 2023 21:59:01 +0000 (UTC) From: Hans de Goede To: Pavel Machek , Lee Jones Cc: Hans de Goede , Johannes Berg , linux-leds@vger.kernel.org Subject: [PATCH 1/4] leds: Change led_trigger_blink[_oneshot]() delay parameters to pass-by-value Date: Wed, 12 Apr 2023 23:58:52 +0200 Message-Id: <20230412215855.593541-2-hdegoede@redhat.com> In-Reply-To: <20230412215855.593541-1-hdegoede@redhat.com> References: <20230412215855.593541-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org led_blink_set[_oneshot]()'s delay_on and delay_off function parameters are pass by reference, so that hw-blink implementations can report back the actual achieved delays when the values have been rounded to something the hw supports. This is really only interesting for the sysfs API / the timer trigger. Other triggers don't really care about this and none of the callers of led_trigger_blink[_oneshot]() do anything with the returned delay values. Change the led_trigger_blink[_oneshot]() delay parameters to pass-by-value, there are 2 reasons for this: 1. led_cdev->blink_set() may sleep, while led_trigger_blink() may not. So on hw where led_cdev->blink_set() sleeps the call needs to be deferred to a workqueue, in which case the actual achieved delays are unknown (this is a preparation patch for the deferring). 2. Since the callers don't care about the actual achieved delays, allowing callers to directly pass a value leads to simpler code for most callers. Signed-off-by: Hans de Goede --- drivers/leds/led-triggers.c | 16 ++++++++-------- drivers/leds/trigger/ledtrig-disk.c | 9 +++------ drivers/leds/trigger/ledtrig-mtd.c | 8 ++------ drivers/net/arcnet/arcnet.c | 8 ++------ drivers/power/supply/power_supply_leds.c | 5 +---- drivers/usb/common/led.c | 4 +--- include/linux/leds.h | 16 ++++++++-------- net/mac80211/led.c | 2 +- net/mac80211/led.h | 8 ++------ net/netfilter/xt_LED.c | 3 +-- 10 files changed, 29 insertions(+), 50 deletions(-) diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 072491d3e17b..e06361165e9b 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -393,8 +393,8 @@ void led_trigger_event(struct led_trigger *trig, EXPORT_SYMBOL_GPL(led_trigger_event); static void led_trigger_blink_setup(struct led_trigger *trig, - unsigned long *delay_on, - unsigned long *delay_off, + unsigned long delay_on, + unsigned long delay_off, int oneshot, int invert) { @@ -406,25 +406,25 @@ static void led_trigger_blink_setup(struct led_trigger *trig, rcu_read_lock(); list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list) { if (oneshot) - led_blink_set_oneshot(led_cdev, delay_on, delay_off, + led_blink_set_oneshot(led_cdev, &delay_on, &delay_off, invert); else - led_blink_set(led_cdev, delay_on, delay_off); + led_blink_set(led_cdev, &delay_on, &delay_off); } rcu_read_unlock(); } void led_trigger_blink(struct led_trigger *trig, - unsigned long *delay_on, - unsigned long *delay_off) + unsigned long delay_on, + unsigned long delay_off) { led_trigger_blink_setup(trig, delay_on, delay_off, 0, 0); } EXPORT_SYMBOL_GPL(led_trigger_blink); void led_trigger_blink_oneshot(struct led_trigger *trig, - unsigned long *delay_on, - unsigned long *delay_off, + unsigned long delay_on, + unsigned long delay_off, int invert) { led_trigger_blink_setup(trig, delay_on, delay_off, 1, invert); diff --git a/drivers/leds/trigger/ledtrig-disk.c b/drivers/leds/trigger/ledtrig-disk.c index 0b7dfbd04273..e9b87ee944f2 100644 --- a/drivers/leds/trigger/ledtrig-disk.c +++ b/drivers/leds/trigger/ledtrig-disk.c @@ -19,16 +19,13 @@ DEFINE_LED_TRIGGER(ledtrig_disk_write); void ledtrig_disk_activity(bool write) { - unsigned long blink_delay = BLINK_DELAY; - - led_trigger_blink_oneshot(ledtrig_disk, - &blink_delay, &blink_delay, 0); + led_trigger_blink_oneshot(ledtrig_disk, BLINK_DELAY, BLINK_DELAY, 0); if (write) led_trigger_blink_oneshot(ledtrig_disk_write, - &blink_delay, &blink_delay, 0); + BLINK_DELAY, BLINK_DELAY, 0); else led_trigger_blink_oneshot(ledtrig_disk_read, - &blink_delay, &blink_delay, 0); + BLINK_DELAY, BLINK_DELAY, 0); } EXPORT_SYMBOL(ledtrig_disk_activity); diff --git a/drivers/leds/trigger/ledtrig-mtd.c b/drivers/leds/trigger/ledtrig-mtd.c index 8fa763c2269b..bbe6876a249d 100644 --- a/drivers/leds/trigger/ledtrig-mtd.c +++ b/drivers/leds/trigger/ledtrig-mtd.c @@ -22,12 +22,8 @@ DEFINE_LED_TRIGGER(ledtrig_nand); void ledtrig_mtd_activity(void) { - unsigned long blink_delay = BLINK_DELAY; - - led_trigger_blink_oneshot(ledtrig_mtd, - &blink_delay, &blink_delay, 0); - led_trigger_blink_oneshot(ledtrig_nand, - &blink_delay, &blink_delay, 0); + led_trigger_blink_oneshot(ledtrig_mtd, BLINK_DELAY, BLINK_DELAY, 0); + led_trigger_blink_oneshot(ledtrig_nand, BLINK_DELAY, BLINK_DELAY, 0); } EXPORT_SYMBOL(ledtrig_mtd_activity); diff --git a/drivers/net/arcnet/arcnet.c b/drivers/net/arcnet/arcnet.c index 1bad1866ae46..99265667538c 100644 --- a/drivers/net/arcnet/arcnet.c +++ b/drivers/net/arcnet/arcnet.c @@ -196,13 +196,10 @@ static void arcnet_dump_packet(struct net_device *dev, int bufnum, void arcnet_led_event(struct net_device *dev, enum arcnet_led_event event) { struct arcnet_local *lp = netdev_priv(dev); - unsigned long led_delay = 350; - unsigned long tx_delay = 50; switch (event) { case ARCNET_LED_EVENT_RECON: - led_trigger_blink_oneshot(lp->recon_led_trig, - &led_delay, &led_delay, 0); + led_trigger_blink_oneshot(lp->recon_led_trig, 350, 350, 0); break; case ARCNET_LED_EVENT_OPEN: led_trigger_event(lp->tx_led_trig, LED_OFF); @@ -213,8 +210,7 @@ void arcnet_led_event(struct net_device *dev, enum arcnet_led_event event) led_trigger_event(lp->recon_led_trig, LED_OFF); break; case ARCNET_LED_EVENT_TX: - led_trigger_blink_oneshot(lp->tx_led_trig, - &tx_delay, &tx_delay, 0); + led_trigger_blink_oneshot(lp->tx_led_trig, 50, 50, 0); break; } } diff --git a/drivers/power/supply/power_supply_leds.c b/drivers/power/supply/power_supply_leds.c index 702bf83f6e6d..e2f554e4e4e6 100644 --- a/drivers/power/supply/power_supply_leds.c +++ b/drivers/power/supply/power_supply_leds.c @@ -22,8 +22,6 @@ static void power_supply_update_bat_leds(struct power_supply *psy) { union power_supply_propval status; - unsigned long delay_on = 0; - unsigned long delay_off = 0; if (power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS, &status)) return; @@ -42,8 +40,7 @@ static void power_supply_update_bat_leds(struct power_supply *psy) led_trigger_event(psy->charging_full_trig, LED_FULL); led_trigger_event(psy->charging_trig, LED_FULL); led_trigger_event(psy->full_trig, LED_OFF); - led_trigger_blink(psy->charging_blink_full_solid_trig, - &delay_on, &delay_off); + led_trigger_blink(psy->charging_blink_full_solid_trig, 0, 0); break; default: led_trigger_event(psy->charging_full_trig, LED_OFF); diff --git a/drivers/usb/common/led.c b/drivers/usb/common/led.c index 0865dd44a80a..1de18d90b134 100644 --- a/drivers/usb/common/led.c +++ b/drivers/usb/common/led.c @@ -14,8 +14,6 @@ #define BLINK_DELAY 30 -static unsigned long usb_blink_delay = BLINK_DELAY; - DEFINE_LED_TRIGGER(ledtrig_usb_gadget); DEFINE_LED_TRIGGER(ledtrig_usb_host); @@ -32,7 +30,7 @@ void usb_led_activity(enum usb_led_event ev) break; } /* led_trigger_blink_oneshot() handles trig == NULL gracefully */ - led_trigger_blink_oneshot(trig, &usb_blink_delay, &usb_blink_delay, 0); + led_trigger_blink_oneshot(trig, BLINK_DELAY, BLINK_DELAY, 0); } EXPORT_SYMBOL_GPL(usb_led_activity); diff --git a/include/linux/leds.h b/include/linux/leds.h index d71201a968b6..6006786cafdc 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -415,11 +415,11 @@ void led_trigger_register_simple(const char *name, struct led_trigger **trigger); void led_trigger_unregister_simple(struct led_trigger *trigger); void led_trigger_event(struct led_trigger *trigger, enum led_brightness event); -void led_trigger_blink(struct led_trigger *trigger, unsigned long *delay_on, - unsigned long *delay_off); +void led_trigger_blink(struct led_trigger *trigger, unsigned long delay_on, + unsigned long delay_off); void led_trigger_blink_oneshot(struct led_trigger *trigger, - unsigned long *delay_on, - unsigned long *delay_off, + unsigned long delay_on, + unsigned long delay_off, int invert); void led_trigger_set_default(struct led_classdev *led_cdev); int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger); @@ -469,11 +469,11 @@ static inline void led_trigger_unregister_simple(struct led_trigger *trigger) {} static inline void led_trigger_event(struct led_trigger *trigger, enum led_brightness event) {} static inline void led_trigger_blink(struct led_trigger *trigger, - unsigned long *delay_on, - unsigned long *delay_off) {} + unsigned long delay_on, + unsigned long delay_off) {} static inline void led_trigger_blink_oneshot(struct led_trigger *trigger, - unsigned long *delay_on, - unsigned long *delay_off, + unsigned long delay_on, + unsigned long delay_off, int invert) {} static inline void led_trigger_set_default(struct led_classdev *led_cdev) {} static inline int led_trigger_set(struct led_classdev *led_cdev, diff --git a/net/mac80211/led.c b/net/mac80211/led.c index 6de8d0ad5497..2dc732147e85 100644 --- a/net/mac80211/led.c +++ b/net/mac80211/led.c @@ -282,7 +282,7 @@ static void tpt_trig_timer(struct timer_list *t) } } - led_trigger_blink(&local->tpt_led, &on, &off); + led_trigger_blink(&local->tpt_led, on, off); } const char * diff --git a/net/mac80211/led.h b/net/mac80211/led.h index b71a1428d883..d25f13346b82 100644 --- a/net/mac80211/led.h +++ b/net/mac80211/led.h @@ -13,22 +13,18 @@ static inline void ieee80211_led_rx(struct ieee80211_local *local) { #ifdef CONFIG_MAC80211_LEDS - unsigned long led_delay = MAC80211_BLINK_DELAY; - if (!atomic_read(&local->rx_led_active)) return; - led_trigger_blink_oneshot(&local->rx_led, &led_delay, &led_delay, 0); + led_trigger_blink_oneshot(&local->rx_led, MAC80211_BLINK_DELAY, MAC80211_BLINK_DELAY, 0); #endif } static inline void ieee80211_led_tx(struct ieee80211_local *local) { #ifdef CONFIG_MAC80211_LEDS - unsigned long led_delay = MAC80211_BLINK_DELAY; - if (!atomic_read(&local->tx_led_active)) return; - led_trigger_blink_oneshot(&local->tx_led, &led_delay, &led_delay, 0); + led_trigger_blink_oneshot(&local->tx_led, MAC80211_BLINK_DELAY, MAC80211_BLINK_DELAY, 0); #endif } diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c index 66b0f941d8fb..36c9720ad8d6 100644 --- a/net/netfilter/xt_LED.c +++ b/net/netfilter/xt_LED.c @@ -43,7 +43,6 @@ led_tg(struct sk_buff *skb, const struct xt_action_param *par) { const struct xt_led_info *ledinfo = par->targinfo; struct xt_led_info_internal *ledinternal = ledinfo->internal_data; - unsigned long led_delay = XT_LED_BLINK_DELAY; /* * If "always blink" is enabled, and there's still some time until the @@ -52,7 +51,7 @@ led_tg(struct sk_buff *skb, const struct xt_action_param *par) if ((ledinfo->delay > 0) && ledinfo->always_blink && timer_pending(&ledinternal->timer)) led_trigger_blink_oneshot(&ledinternal->netfilter_led_trigger, - &led_delay, &led_delay, 1); + XT_LED_BLINK_DELAY, XT_LED_BLINK_DELAY, 1); else led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL); From patchwork Wed Apr 12 21:58:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 672753 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7BF5C77B6C for ; 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Wed, 12 Apr 2023 17:59:04 -0400 X-MC-Unique: nCjSTX3wMESZc9YcmrFnVg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D03AE85A588; Wed, 12 Apr 2023 21:59:03 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.192.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1E8731121320; Wed, 12 Apr 2023 21:59:03 +0000 (UTC) From: Hans de Goede To: Pavel Machek , Lee Jones Cc: Hans de Goede , Johannes Berg , linux-leds@vger.kernel.org Subject: [PATCH 2/4] leds: Fix set_brightness_delayed() race Date: Wed, 12 Apr 2023 23:58:53 +0200 Message-Id: <20230412215855.593541-3-hdegoede@redhat.com> In-Reply-To: <20230412215855.593541-1-hdegoede@redhat.com> References: <20230412215855.593541-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org When a trigger wants to switch from blinking to LED on it needs to call: led_set_brightness(LED_OFF); led_set_brightness(LED_FULL); To first call disables blinking and the second then turns the LED on (the power-supply charging-blink-full-solid triggers do this). These calls happen immediately after each other, so it is possible that set_brightness_delayed() from the first call has not run yet when the led_set_brightness(LED_FULL) call finishes. If this race hits then this is causing problems for both sw- and hw-blinking: For sw-blinking set_brightness_delayed() clears delayed_set_value when LED_BLINK_DISABLE is set causing the led_set_brightness(LED_FULL) call effects to get lost when hitting the race, resulting in the LED turning off instead of on. For hw-blinking if the race hits delayed_set_value has been set to LED_FULL by the time set_brightness_delayed() runs. So led_cdev->brightness_set_blocking() is never called with LED_OFF as argument and the hw-blinking is never disabled leaving the LED blinking instead of on. Fix both issues by adding LED_SET_BRIGHTNESS and LED_SET_BRIGHTNESS_OFF work_flags making this 2 separate actions to be run by set_brightness_delayed(). Signed-off-by: Hans de Goede --- drivers/leds/led-core.c | 57 +++++++++++++++++++++++++++++++---------- include/linux/leds.h | 3 +++ 2 files changed, 47 insertions(+), 13 deletions(-) diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c index 4a97cb745788..e61acc785410 100644 --- a/drivers/leds/led-core.c +++ b/drivers/leds/led-core.c @@ -114,21 +114,14 @@ static void led_timer_function(struct timer_list *t) mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay)); } -static void set_brightness_delayed(struct work_struct *ws) +static void set_brightness_delayed_set_brightness(struct led_classdev *led_cdev, + unsigned int value) { - struct led_classdev *led_cdev = - container_of(ws, struct led_classdev, set_brightness_work); int ret = 0; - if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) { - led_cdev->delayed_set_value = LED_OFF; - led_stop_software_blink(led_cdev); - } - - ret = __led_set_brightness(led_cdev, led_cdev->delayed_set_value); + ret = __led_set_brightness(led_cdev, value); if (ret == -ENOTSUPP) - ret = __led_set_brightness_blocking(led_cdev, - led_cdev->delayed_set_value); + ret = __led_set_brightness_blocking(led_cdev, value); if (ret < 0 && /* LED HW might have been unplugged, therefore don't warn */ !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) && @@ -137,6 +130,30 @@ static void set_brightness_delayed(struct work_struct *ws) "Setting an LED's brightness failed (%d)\n", ret); } +static void set_brightness_delayed(struct work_struct *ws) +{ + struct led_classdev *led_cdev = + container_of(ws, struct led_classdev, set_brightness_work); + + if (test_and_clear_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) { + led_stop_software_blink(led_cdev); + set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags); + } + + /* + * Triggers may call led_set_brightness(LED_OFF), + * led_set_brightness(LED_FULL) in quick succession to disable blinking + * and turn the LED on. Both actions may have been scheduled to run + * before this work item runs once. To make sure this works properly + * handle LED_SET_BRIGHTNESS_OFF first. + */ + if (test_and_clear_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags)) + set_brightness_delayed_set_brightness(led_cdev, LED_OFF); + + if (test_and_clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags)) + set_brightness_delayed_set_brightness(led_cdev, led_cdev->delayed_set_value); +} + static void led_set_software_blink(struct led_classdev *led_cdev, unsigned long delay_on, unsigned long delay_off) @@ -271,8 +288,22 @@ void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value) if (!__led_set_brightness(led_cdev, value)) return; - /* If brightness setting can sleep, delegate it to a work queue task */ - led_cdev->delayed_set_value = value; + /* + * Brightness setting can sleep, delegate it to a work queue task. + * value 0 / LED_OFF is special, since it also disables hw-blinking + * (sw-blink disable is handled in led_set_brightness()). + * To avoid a hw-blink-disable getting lost when a second brightness + * change is done immediately afterwards (before the work runs), + * it uses a separate work_flag. + */ + if (value) { + led_cdev->delayed_set_value = value; + set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags); + } else { + clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags); + set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags); + } + schedule_work(&led_cdev->set_brightness_work); } EXPORT_SYMBOL_GPL(led_set_brightness_nopm); diff --git a/include/linux/leds.h b/include/linux/leds.h index 6006786cafdc..eb68aea79c6d 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -116,6 +116,9 @@ struct led_classdev { #define LED_BLINK_INVERT 3 #define LED_BLINK_BRIGHTNESS_CHANGE 4 #define LED_BLINK_DISABLE 5 + /* Brightness off also disables hw-blinking so it is a separate action */ +#define LED_SET_BRIGHTNESS_OFF 6 +#define LED_SET_BRIGHTNESS 7 /* Set LED brightness level * Must not sleep. Use brightness_set_blocking for drivers From patchwork Wed Apr 12 21:58:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 673729 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E286C7619A for ; Wed, 12 Apr 2023 21:59:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229878AbjDLV7u (ORCPT ); Wed, 12 Apr 2023 17:59:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229535AbjDLV7t (ORCPT ); Wed, 12 Apr 2023 17:59:49 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D953C0 for ; Wed, 12 Apr 2023 14:59:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681336746; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cP21nVIy9V2fX3qGndHxD2YCR9T8vu9orLQhMMtwepg=; b=PxVohEUMe2K6KkYPRToUlkRF8HfnLVBQjvgt5XOzORAjqDDgDXhgmOayNmropeCWWkmRAy jP97lQiMzxOyK7WfFajdMq7cGuhh2BehTJoCcAaSJPzSD6D0fHYd6Sqm6jqn9A7keyxyr+ 1FxlxqasNz5tOt9512I57iePB+WQyo0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-646-v9naLjsYOMuuaHKAAKOjRg-1; Wed, 12 Apr 2023 17:59:05 -0400 X-MC-Unique: v9naLjsYOMuuaHKAAKOjRg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BF229830F9E; Wed, 12 Apr 2023 21:59:04 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.192.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0C6881121320; Wed, 12 Apr 2023 21:59:03 +0000 (UTC) From: Hans de Goede To: Pavel Machek , Lee Jones Cc: Hans de Goede , Johannes Berg , linux-leds@vger.kernel.org Subject: [PATCH 3/4] leds: Fix oops about sleeping in led_trigger_blink() Date: Wed, 12 Apr 2023 23:58:54 +0200 Message-Id: <20230412215855.593541-4-hdegoede@redhat.com> In-Reply-To: <20230412215855.593541-1-hdegoede@redhat.com> References: <20230412215855.593541-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org led_trigger_blink() calls led_blink_set() from a RCU read-side critical section so led_blink_set() must not sleep. Note sleeping was not allowed before the switch to RCU either because a spinlock was held before. led_blink_set() does not sleep when sw-blinking is used, but many LED controller drivers with hw blink support have a blink_set function which may sleep, leading to an oops like this one: [ 832.605062] ------------[ cut here ]------------ [ 832.605085] Voluntary context switch within RCU read-side critical section! [ 832.605119] WARNING: CPU: 2 PID: 370 at kernel/rcu/tree_plugin.h:318 rcu_note_context_switch+0x4ee/0x690 [ 832.606453] Call Trace: [ 832.606466] [ 832.606487] __schedule+0x9f/0x1480 [ 832.606527] schedule+0x5d/0xe0 [ 832.606549] schedule_timeout+0x79/0x140 [ 832.606572] ? __pfx_process_timeout+0x10/0x10 [ 832.606599] wait_for_completion_timeout+0x6f/0x140 [ 832.606627] i2c_dw_xfer+0x101/0x460 [ 832.606659] ? psi_group_change+0x168/0x400 [ 832.606680] __i2c_transfer+0x172/0x6d0 [ 832.606709] i2c_smbus_xfer_emulated+0x27d/0x9c0 [ 832.606732] ? __schedule+0x430/0x1480 [ 832.606753] ? preempt_count_add+0x6a/0xa0 [ 832.606778] ? get_nohz_timer_target+0x18/0x190 [ 832.606796] ? lock_timer_base+0x61/0x80 [ 832.606817] ? preempt_count_add+0x6a/0xa0 [ 832.606842] __i2c_smbus_xfer+0xa2/0x3f0 [ 832.606862] i2c_smbus_xfer+0x66/0xf0 [ 832.606882] i2c_smbus_read_byte_data+0x41/0x70 [ 832.606901] ? _raw_spin_unlock_irqrestore+0x23/0x40 [ 832.606922] ? __pm_runtime_suspend+0x46/0xc0 [ 832.606946] cht_wc_byte_reg_read+0x2e/0x60 [ 832.606972] _regmap_read+0x5c/0x120 [ 832.606997] _regmap_update_bits+0x96/0xc0 [ 832.607023] regmap_update_bits_base+0x5b/0x90 [ 832.607053] cht_wc_leds_brightness_get+0x412/0x910 [leds_cht_wcove] [ 832.607094] led_blink_setup+0x28/0x100 [ 832.607119] led_trigger_blink+0x40/0x70 [ 832.607145] power_supply_update_leds+0x1b7/0x1c0 [ 832.607174] power_supply_changed_work+0x67/0xe0 [ 832.607198] process_one_work+0x1c8/0x3c0 [ 832.607222] worker_thread+0x4d/0x380 [ 832.607243] ? __pfx_worker_thread+0x10/0x10 [ 832.607258] kthread+0xe9/0x110 [ 832.607279] ? __pfx_kthread+0x10/0x10 [ 832.607300] ret_from_fork+0x2c/0x50 [ 832.607337] [ 832.607344] ---[ end trace 0000000000000000 ]--- Add a new led_blink_set_nosleep() function which defers the actual led_blink_set() call to a workqueue when necessary to fix this. This also fixes an existing race where a pending led_set_brightness() has been deferred to set_brightness_work and might then race with a later led_cdev->blink_set() call. Note this race is only an issue with triggers mixing led_trigger_event() and led_trigger_blink() calls, sysfs API calls and led_trigger_blink_oneshot() are not affected. Note rather then adding a separate blink_set_blocking callback this uses the presence of the already existing brightness_set_blocking callback to detect if the blinking call should be deferred to set_brightness_work. Signed-off-by: Hans de Goede --- drivers/leds/led-core.c | 24 ++++++++++++++++++++++++ drivers/leds/led-triggers.c | 2 +- include/linux/leds.h | 24 ++++++++++++++++++++++++ 3 files changed, 49 insertions(+), 1 deletion(-) diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c index e61acc785410..b9b1295833c9 100644 --- a/drivers/leds/led-core.c +++ b/drivers/leds/led-core.c @@ -152,6 +152,13 @@ static void set_brightness_delayed(struct work_struct *ws) if (test_and_clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags)) set_brightness_delayed_set_brightness(led_cdev, led_cdev->delayed_set_value); + + if (test_and_clear_bit(LED_SET_BLINK, &led_cdev->work_flags)) { + unsigned long delay_on = led_cdev->delayed_delay_on; + unsigned long delay_off = led_cdev->delayed_delay_off; + + led_blink_set(led_cdev, &delay_on, &delay_off); + } } static void led_set_software_blink(struct led_classdev *led_cdev, @@ -246,6 +253,22 @@ void led_blink_set_oneshot(struct led_classdev *led_cdev, } EXPORT_SYMBOL_GPL(led_blink_set_oneshot); +void led_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on, + unsigned long delay_off) +{ + /* If necessary delegate to a work queue task. */ + if (led_cdev->blink_set && led_cdev->brightness_set_blocking) { + led_cdev->delayed_delay_on = delay_on; + led_cdev->delayed_delay_off = delay_off; + set_bit(LED_SET_BLINK, &led_cdev->work_flags); + schedule_work(&led_cdev->set_brightness_work); + return; + } + + led_blink_set(led_cdev, &delay_on, &delay_off); +} +EXPORT_SYMBOL_GPL(led_blink_set_nosleep); + void led_stop_software_blink(struct led_classdev *led_cdev) { del_timer_sync(&led_cdev->blink_timer); @@ -301,6 +324,7 @@ void led_set_brightness_nopm(struct led_classdev *led_cdev, unsigned int value) set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags); } else { clear_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags); + clear_bit(LED_SET_BLINK, &led_cdev->work_flags); set_bit(LED_SET_BRIGHTNESS_OFF, &led_cdev->work_flags); } diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index e06361165e9b..8214d3f7bc5f 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -409,7 +409,7 @@ static void led_trigger_blink_setup(struct led_trigger *trig, led_blink_set_oneshot(led_cdev, &delay_on, &delay_off, invert); else - led_blink_set(led_cdev, &delay_on, &delay_off); + led_blink_set_nosleep(led_cdev, delay_on, delay_off); } rcu_read_unlock(); } diff --git a/include/linux/leds.h b/include/linux/leds.h index eb68aea79c6d..3c93dec3f4e2 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -119,6 +119,7 @@ struct led_classdev { /* Brightness off also disables hw-blinking so it is a separate action */ #define LED_SET_BRIGHTNESS_OFF 6 #define LED_SET_BRIGHTNESS 7 +#define LED_SET_BLINK 8 /* Set LED brightness level * Must not sleep. Use brightness_set_blocking for drivers @@ -142,6 +143,10 @@ struct led_classdev { * match the values specified exactly. * Deactivate blinking again when the brightness is set to LED_OFF * via the brightness_set() callback. + * For led_blink_set_nosleep() the LED core assumes that blink_set + * implementations, of drivers which do not use brightness_set_blocking, + * will not sleep. Therefor if brightness_set_blocking is not set + * this function must not sleep! */ int (*blink_set)(struct led_classdev *led_cdev, unsigned long *delay_on, @@ -165,6 +170,8 @@ struct led_classdev { struct work_struct set_brightness_work; int delayed_set_value; + unsigned long delayed_delay_on; + unsigned long delayed_delay_off; #ifdef CONFIG_LEDS_TRIGGERS /* Protects the trigger data below */ @@ -257,12 +264,27 @@ struct led_classdev *__must_check devm_of_led_get(struct device *dev, * software blinking if there is no hardware blinking or if * the LED refuses the passed values. * + * This function may sleep! + * * Note that if software blinking is active, simply calling * led_cdev->brightness_set() will not stop the blinking, * use led_classdev_brightness_set() instead. */ void led_blink_set(struct led_classdev *led_cdev, unsigned long *delay_on, unsigned long *delay_off); + +/** + * led_blink_set_nosleep - set blinking, guaranteed to not sleep + * @led_cdev: the LED to start blinking + * @delay_on: the time it should be on (in ms) + * @delay_off: the time it should ble off (in ms) + * + * This function makes the LED blink and is guaranteed to not sleep. Otherwise + * this is the same as led_blink_set(), see led_blink_set() for details. + */ +void led_blink_set_nosleep(struct led_classdev *led_cdev, unsigned long delay_on, + unsigned long delay_off); + /** * led_blink_set_oneshot - do a oneshot software blink * @led_cdev: the LED to start blinking @@ -276,6 +298,8 @@ void led_blink_set(struct led_classdev *led_cdev, unsigned long *delay_on, * * If invert is set, led blinks for delay_off first, then for * delay_on and leave the led on after the on-off cycle. + * + * This function is guaranteed not to sleep. */ void led_blink_set_oneshot(struct led_classdev *led_cdev, unsigned long *delay_on, unsigned long *delay_off, From patchwork Wed Apr 12 21:58:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 672751 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59852C7619A for ; Wed, 12 Apr 2023 21:59:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229854AbjDLV7y (ORCPT ); Wed, 12 Apr 2023 17:59:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229870AbjDLV7u (ORCPT ); Wed, 12 Apr 2023 17:59:50 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1399155BD for ; Wed, 12 Apr 2023 14:59:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681336747; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JYHeE+jv2rqhDXwZdqxAf5qYQffkNx3KctvdgEemDUA=; b=RpNbjygC6O8Bq75fy4SyVRcYshhNobJwKC5Z+1iPVACwc2KWABWWOJZpJnRnwqgWV2r0nK xdjfYlipTYEPqVH3Oxnvcjg4FHWul0XYKnKoFkPYfCwxd8Af4s3/8e4MUAdtuC6ZZu+EfK IRoWb7t0D4nwoWeUwVf5vQjgaZKZjCU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-54-VaBf7Bm0NiiHbOAZjXecVw-1; Wed, 12 Apr 2023 17:59:06 -0400 X-MC-Unique: VaBf7Bm0NiiHbOAZjXecVw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id ACC18800B23; Wed, 12 Apr 2023 21:59:05 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.192.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id EF40E1121320; Wed, 12 Apr 2023 21:59:04 +0000 (UTC) From: Hans de Goede To: Pavel Machek , Lee Jones Cc: Hans de Goede , Johannes Berg , linux-leds@vger.kernel.org Subject: [PATCH 4/4] leds: Clear LED_INIT_DEFAULT_TRIGGER when clearing current trigger Date: Wed, 12 Apr 2023 23:58:55 +0200 Message-Id: <20230412215855.593541-5-hdegoede@redhat.com> In-Reply-To: <20230412215855.593541-1-hdegoede@redhat.com> References: <20230412215855.593541-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org Not all triggers use LED_INIT_DEFAULT_TRIGGER, which means that it will not get cleared when the default trigger is a trigger which does not use it such as "default-on". If the default trigger then later gets replaced by a trigger which does check LED_INIT_DEFAULT_TRIGGER, such as "timer" then that trigger will behave as if it is the default trigger which it should not do. To fix this clear the LED_INIT_DEFAULT_TRIGGER flag when clearing the current trigger, so that it will not be set for any subsequently set (non default) triggers. Signed-off-by: Hans de Goede --- drivers/leds/led-triggers.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c index 8214d3f7bc5f..6a5e1f41f9a4 100644 --- a/drivers/leds/led-triggers.c +++ b/drivers/leds/led-triggers.c @@ -185,6 +185,7 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig) led_cdev->trigger = NULL; led_cdev->trigger_data = NULL; led_cdev->activated = false; + led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER; led_set_brightness(led_cdev, LED_OFF); } if (trig) {