{"id":2223411,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2223411/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pwm/patch/20260415093433.2359955-1-sangyun.kim@snu.ac.kr/","project":{"id":38,"url":"http://patchwork.ozlabs.org/api/1.1/projects/38/?format=json","name":"Linux PWM development","link_name":"linux-pwm","list_id":"linux-pwm.vger.kernel.org","list_email":"linux-pwm@vger.kernel.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260415093433.2359955-1-sangyun.kim@snu.ac.kr>","date":"2026-04-15T09:34:33","name":"pwm: atmel-tcb: Fix sleeping function called from invalid context","commit_ref":null,"pull_url":null,"state":"changes-requested","archived":false,"hash":"14287fff69fabca2d5b4e3d4c17c6f17cc44f26b","submitter":{"id":93159,"url":"http://patchwork.ozlabs.org/api/1.1/people/93159/?format=json","name":"Sangyun Kim","email":"sangyun.kim@snu.ac.kr"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pwm/patch/20260415093433.2359955-1-sangyun.kim@snu.ac.kr/mbox/","series":[{"id":499949,"url":"http://patchwork.ozlabs.org/api/1.1/series/499949/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pwm/list/?series=499949","date":"2026-04-15T09:34:33","name":"pwm: atmel-tcb: Fix sleeping function called from invalid context","version":1,"mbox":"http://patchwork.ozlabs.org/series/499949/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2223411/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2223411/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pwm@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=snu.ac.kr header.i=@snu.ac.kr header.a=rsa-sha256\n header.s=google header.b=lpHlEmA7;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; helo=tor.lore.kernel.org;\n envelope-from=linux-pwm+bounces-8582-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (1024-bit key) header.d=snu.ac.kr header.i=@snu.ac.kr\n header.b=\"lpHlEmA7\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=209.85.214.174","smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=snu.ac.kr","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=snu.ac.kr"],"Received":["from tor.lore.kernel.org (tor.lore.kernel.org\n [IPv6:2600:3c04:e001:36c::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fwbbR5Yz4z1yCv\n\tfor ; Wed, 15 Apr 2026 19:35:15 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby tor.lore.kernel.org (Postfix) with ESMTP id DB11F3012CE9\n\tfor ; Wed, 15 Apr 2026 09:34:54 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 4CC2131B80E;\n\tWed, 15 Apr 2026 09:34:53 +0000 (UTC)","from mail-pl1-f174.google.com (mail-pl1-f174.google.com\n [209.85.214.174])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 0938C33A71B\n\tfor ; Wed, 15 Apr 2026 09:34:48 +0000 (UTC)","by mail-pl1-f174.google.com with SMTP id\n d9443c01a7336-2ad9a9be502so40088645ad.0\n for ; Wed, 15 Apr 2026 02:34:48 -0700 (PDT)","from nunu.. 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Kim ","To":"ukleinek@kernel.org","Cc":"nicolas.ferre@microchip.com,\n\talexandre.belloni@bootlin.com,\n\tclaudiu.beznea@tuxon.dev,\n\tlinux-pwm@vger.kernel.org,\n\tlinux-arm-kernel@lists.infradead.org,\n\tlinux-kernel@vger.kernel.org","Subject":"[PATCH] pwm: atmel-tcb: Fix sleeping function called from invalid\n context","Date":"Wed, 15 Apr 2026 18:34:33 +0900","Message-Id":"<20260415093433.2359955-1-sangyun.kim@snu.ac.kr>","X-Mailer":"git-send-email 2.34.1","Precedence":"bulk","X-Mailing-List":"linux-pwm@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit"},"content":"atmel_tcb_pwm_apply() holds tcbpwmc->lock as a spinlock via\nguard(spinlock)() and then calls atmel_tcb_pwm_config(), which calls\nclk_get_rate() twice. clk_get_rate() acquires clk_prepare_lock (a\nmutex), so this is a sleep-in-atomic-context violation.\n\nOn CONFIG_DEBUG_ATOMIC_SLEEP kernels every pwm_apply_state() that\nenables or reconfigures the PWM triggers a \"BUG: sleeping function\ncalled from invalid context\" warning.\n\nAll callers of tcbpwmc->lock (the .request and .apply callbacks) run in\nprocess context and only need mutual exclusion against each other, so\nuse a mutex instead of a spinlock and allow the sleeping calls inside\natmel_tcb_pwm_config().\n\nFixes: 37f7707077f5 (\"pwm: atmel-tcb: Fix race condition and convert to guards\")\nSigned-off-by: Sangyun Kim \n---\n drivers/pwm/pwm-atmel-tcb.c | 9 +++++----\n 1 file changed, 5 insertions(+), 4 deletions(-)","diff":"diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c\nindex f9ff78ba122d..6405e82d9f10 100644\n--- a/drivers/pwm/pwm-atmel-tcb.c\n+++ b/drivers/pwm/pwm-atmel-tcb.c\n@@ -17,6 +17,7 @@\n #include \n #include \n #include \n+#include \n #include \n #include \n #include \n@@ -47,7 +48,7 @@ struct atmel_tcb_channel {\n };\n \n struct atmel_tcb_pwm_chip {\n-\tspinlock_t lock;\n+\tstruct mutex lock;\n \tu8 channel;\n \tu8 width;\n \tstruct regmap *regmap;\n@@ -81,7 +82,7 @@ static int atmel_tcb_pwm_request(struct pwm_chip *chip,\n \ttcbpwm->period = 0;\n \ttcbpwm->div = 0;\n \n-\tguard(spinlock)(&tcbpwmc->lock);\n+\tguard(mutex)(&tcbpwmc->lock);\n \n \tregmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);\n \t/*\n@@ -335,7 +336,7 @@ static int atmel_tcb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,\n \tint duty_cycle, period;\n \tint ret;\n \n-\tguard(spinlock)(&tcbpwmc->lock);\n+\tguard(mutex)(&tcbpwmc->lock);\n \n \tif (!state->enabled) {\n \t\tatmel_tcb_pwm_disable(chip, pwm, state->polarity);\n@@ -438,7 +439,7 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev)\n \tif (err)\n \t\tgoto err_gclk;\n \n-\tspin_lock_init(&tcbpwmc->lock);\n+\tmutex_init(&tcbpwmc->lock);\n \n \terr = pwmchip_add(chip);\n \tif (err < 0)\n","prefixes":[]}