From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D627A46B5 for ; Mon, 16 Jan 2023 16:29:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 598F6C433D2; Mon, 16 Jan 2023 16:29:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673886559; bh=s5d8qjGwlphUnBSAHLDRvuazw7pkrVfwwO4buH/pA+I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xBZmPK+k8RJV/3IctZfn8EGjMFjtSQHMlZ15UQFiJKNonRseBCT5iqWgCSaEb5uxD wJWTuNMCnsvPOhnQF55i5NspTtXTsHxerqS5bQxg7W3kxCD9jLnfVJxO2goiin29iu +ZIQ961vkz1yld6XpTD8/Xe2zRVP86gOpe+cGAj8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Johan Hovold , Mark Brown Subject: [PATCH 5.4 449/658] regulator: core: fix deadlock on regulator enable Date: Mon, 16 Jan 2023 16:48:57 +0100 Message-Id: <20230116154930.037951154@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Johan Hovold commit cb3543cff90a4448ed560ac86c98033ad5fecda9 upstream. When updating the operating mode as part of regulator enable, the caller has already locked the regulator tree and drms_uA_update() must not try to do the same in order not to trigger a deadlock. The lock inversion is reported by lockdep as: ====================================================== WARNING: possible circular locking dependency detected 6.1.0-next-20221215 #142 Not tainted ------------------------------------------------------ udevd/154 is trying to acquire lock: ffffc11f123d7e50 (regulator_list_mutex){+.+.}-{3:3}, at: regulator_lock_dependent+0x54/0x280 but task is already holding lock: ffff80000e4c36e8 (regulator_ww_class_acquire){+.+.}-{0:0}, at: regulator_enable+0x34/0x80 which lock already depends on the new lock. ... Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(regulator_ww_class_acquire); lock(regulator_list_mutex); lock(regulator_ww_class_acquire); lock(regulator_list_mutex); *** DEADLOCK *** just before probe of a Qualcomm UFS controller (occasionally) deadlocks when enabling one of its regulators. Fixes: 9243a195be7a ("regulator: core: Change voltage setting path") Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking") Cc: stable@vger.kernel.org # 5.0 Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20221215104646.19818-1-johan+linaro@kernel.org Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- drivers/regulator/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -956,7 +956,7 @@ static int drms_uA_update(struct regulat /* get input voltage */ input_uV = 0; if (rdev->supply) - input_uV = regulator_get_voltage(rdev->supply); + input_uV = regulator_get_voltage_rdev(rdev->supply->rdev); if (input_uV <= 0) input_uV = rdev->constraints->input_uV; if (input_uV <= 0) {