From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (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 28ACF4C6808 for ; Mon, 7 Sep 2026 12:47:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788785238; cv=none; b=u1Zyukj2HFJFEAsiKNLG58nrAaikElAmd917ezh7SimKMuq5YL8Be96uA/lEBWAIBM3dvSA90usFwtLehYiJHEnUTrGcfRpUBC2p1mhlBnC6LiJMTiLxVI6OU6MNujiBGIv1z3qFaa+1k9GzBCU/yH1cnGTCzPEoTIXhBAhFY1k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788785238; c=relaxed/simple; bh=UgqDmnOVqopm2mbDfHXbWFiQUAGdMzePQRCHXpsq6lA=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pMV1L+DzxZ4sYXmyazEv2brTyjuihHLIqdZaXP2QCg5JoEXaG2Up5K9EjdVQfHzkjqoMwFn9RMZTkc/PW9f6HF38WCFV8yrCFZK+22POfeRKTz5gjTVRVR0c1axcgdxU0mQjXL7/VZAV/9h8z9XEdqotM+3NUMGYoVdqGlAXZrk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=BnoIMUBO; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="BnoIMUBO" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 9634E1A1A33; Mon, 7 Sep 2026 12:47:13 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 6ABA960383; Mon, 7 Sep 2026 12:47:13 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 162DE11C79257; Mon, 7 Sep 2026 14:47:07 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1788785228; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=szJ77LlzQz7Ivcsto15zZ6XkZ55IboGYb8ikcqOxE5w=; b=BnoIMUBOeFX08NQhfvjdSrCFStHaTz/lpCPaal1K3WXso7wiTchmZxTqOHHixsAbnryG/F 1c0RjN73scp7p2Ffi2BRj8bNfFCMnXa5nclbgso/CLXLReaQj2wlJy7/7oBgdStF5B3/Xv SPVYMlqBbEhv6dRqH/y+0hBd8AEvZ1Xouj4UWrRPPIN0SLq7yt0QONIOdapXp0uJkhwlRQ ZPVZBUykNPkaZAb1UEPfWsUzZkEcopYAr1nSZd8kL+7oENqjn5RsZzIC95+eprc/vahOzv UDkaiTdKLm3SM7Kd2a10VzgXaKsJA5zySJp1Gea8M+86q50FsSpCgSF4ERkwZw== From: =?utf-8?q?Beno=C3=AEt_Monin?= Date: Mon, 07 Sep 2026 14:46:35 +0200 Subject: [PATCH v3 1/5] irqchip/mips-gic: Fix unbalanced cm_core_lock in for_each_online_cpu_gic() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Message-Id: <20260907-sync-gic-counters-v3-1-3d891ddabdaf@bootlin.com> References: <20260907-sync-gic-counters-v3-0-3d891ddabdaf@bootlin.com> In-Reply-To: <20260907-sync-gic-counters-v3-0-3d891ddabdaf@bootlin.com> To: Thomas Bogendoerfer , Daniel Lezcano , Thomas Gleixner , Dragan Mladjenovic , Chao-ying Fu , Aleksandar Rikalo , Paul Burton , Radu Rendec Cc: Vladimir Kondratiev , Tawfik Bayouk , Gregory CLEMENT , =?utf-8?q?Th=C3=A9o_Lebrun?= , Thomas Petazzoni , linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Beno=C3=AEt_Monin?= X-Mailer: b4 0.16.0 X-Last-TLS-Session-Version: TLSv1.3 Commit d9e2ed610a60 ("irqchip/mips-gic: Support multi-cluster in for_each_online_cpu_gic()") added a gic_unlock_cluster() call to the macro's loop increment, which unconditionally invokes mips_cm_unlock_other() on multi-cluster systems. However nothing in the loop ever acquires the corresponding mips_cm_lock_other(), so on multi-cluster hardware every invocation of for_each_online_cpu_gic() releases an unheld per-CPU cm_core_lock. With CONFIG_PROVE_LOCKING this triggers a "bad unlock balance detected" warning at boot, e.g. from gic_irq_domain_map() while mapping local interrupts. Only the first occurrence is reported, since the first warning permanently disables lockdep (debug_locks = 0); the unbalanced release itself silently persists. Fix this by moving both the acquire and release into __gic_with_next_online_cpu() so they stay balanced. When advancing to a CPU in a remote cluster, lock the CM redirect block for that cluster via mips_cm_lock_other(); when leaving a remote cluster (or finishing the iteration) release it with mips_cm_unlock_other(). Local-cluster CPUs require no locking, so single-cluster systems are unaffected. This also makes the redirect region behave correctly when accessing local register blocks of CPUs in other clusters. Drop the now-unused gic_unlock_cluster() helper and its call from the for_each_online_cpu_gic() increment. Fixes: d9e2ed610a60 ("irqchip/mips-gic: Support multi-cluster in for_each_online_cpu_gic()") Signed-off-by: Benoît Monin --- drivers/irqchip/irq-mips-gic.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c index 19a57c5e2b2e..3b31cbcbed6f 100644 --- a/drivers/irqchip/irq-mips-gic.c +++ b/drivers/irqchip/irq-mips-gic.c @@ -70,6 +70,10 @@ static int __gic_with_next_online_cpu(int prev) { unsigned int cpu; + /* Release the redirect/other region lock to the previous CPU, if any. */ + if (prev >= 0) + mips_cm_unlock_other(); + /* Discover the next online CPU */ cpu = cpumask_next(prev, cpu_online_mask); @@ -77,23 +81,12 @@ static int __gic_with_next_online_cpu(int prev) if (cpu >= nr_cpu_ids) return cpu; - /* - * Move the access lock to the next CPU's GIC local register block. - * - * Set GIC_VL_OTHER. Since the caller holds gic_lock nothing can - * clobber the written value. - */ - write_gic_vl_other(mips_cm_vp_id(cpu)); + /* Lock access to redirect/other region to the next CPU */ + mips_cm_lock_other_cpu(cpu, CM_GCR_Cx_OTHER_BLOCK_LOCAL); return cpu; } -static inline void gic_unlock_cluster(void) -{ - if (mips_cps_multicluster_cpus()) - mips_cm_unlock_other(); -} - /** * for_each_online_cpu_gic() - Iterate over online CPUs, access local registers * @cpu: An integer variable to hold the current CPU number @@ -108,7 +101,6 @@ static inline void gic_unlock_cluster(void) guard(raw_spinlock_irqsave)(gic_lock); \ for ((cpu) = __gic_with_next_online_cpu(-1); \ (cpu) < nr_cpu_ids; \ - gic_unlock_cluster(), \ (cpu) = __gic_with_next_online_cpu(cpu)) /** -- 2.55.0