From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 3580A426696; Thu, 9 Jul 2026 16:28:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783614491; cv=none; b=bycjUJHxpf9+Cld11DJEBznxQ+KH+scgZYOfesZgIdNOkf34sxuc0RcA2uFZOYrJ87j/tT/kBID+rGlvIyoB+DreWoHLngomsMLcmjBXlzKJ6BDE7FlSR5ONofyJ0zSBqC+fkI9iyQp1Zg2dWXVriVK2CAjRKAJqwxbTzthXtps= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783614491; c=relaxed/simple; bh=+EagzDCC+/tQ5DXS2t9l0lamK9cl+N/5MX49+isGQNU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=q4ne8n9QVtYfMMT3ohzj7VNNwyDCammDWeSzbAZVoMAp5efznFUAUIE+ojAn6NHDokeu4cEef6/PFO7RfVlNPeN6xV57LaBWqjPpxUrQejDKeKwHFdOim9ovgQwxHodkImQVeIK/1Tkrc5Q09+O6XRBtfdlic8VUYrmP9SvWJFc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 Received: by smtp.kernel.org (Postfix) with ESMTPSA id D43FB1F00A3A; Thu, 9 Jul 2026 16:28:09 +0000 (UTC) From: Dave Jiang To: linux-acpi@vger.kernel.org, linux-cxl@vger.kernel.org Cc: rafael@kernel.org, tony.luck@intel.com, bp@alien8.de, guohanjun@huawei.com, mchehab@kernel.org, xueshuai@linux.alibaba.com Subject: [PATCH 1/4] ACPI: APEI: GHES: Use spin_lock_irqsave() for CXL CPER work locks Date: Thu, 9 Jul 2026 09:28:04 -0700 Message-ID: <20260709162807.1957783-2-dave.jiang@intel.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260709162807.1957783-1-dave.jiang@intel.com> References: <20260709162807.1957783-1-dave.jiang@intel.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit cxl_cper_post_event() and cxl_cper_post_prot_err() acquire cxl_cper_work_lock and cxl_cper_prot_err_work_lock with spin_lock_irqsave(). These producers run from ghes_do_proc() in hard IRQ context (the GHES IRQ handler) and, for SEA/NMI notifications, from NMI context. The register/unregister helpers take the same two locks with a plain spin_lock() from process context (cxl_ras_init()/cxl_ras_exit() at module load and unload). If a GHES error interrupt is delivered to a CPU that is holding one of these locks via the plain spin_lock(), the interrupt handler's spin_lock_irqsave() on the same lock spins forever against a lock the interrupted thread can no longer release. Take these locks with spin_lock_irqsave() on the register/unregister paths as well. Link: https://sashiko.dev/#/patchset/20260617-topics-ahmtib01-ras_ffh_arm_internal_review-v6-0-91f725174aa0@arm.com?part=6 Fixes: 5e4a264bf8b5 ("acpi/ghes: Process CXL Component Events") Fixes: 36f257e3b0ba ("acpi/ghes, cxl/pci: Process CXL CPER Protocol Errors") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Dave Jiang --- drivers/acpi/apei/ghes.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 3236a3ce79d6..9b6917698ed2 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -783,7 +783,7 @@ int cxl_cper_register_prot_err_work(struct work_struct *work) if (cxl_cper_prot_err_work) return -EINVAL; - guard(spinlock)(&cxl_cper_prot_err_work_lock); + guard(spinlock_irqsave)(&cxl_cper_prot_err_work_lock); cxl_cper_prot_err_work = work; return 0; } @@ -794,7 +794,7 @@ int cxl_cper_unregister_prot_err_work(struct work_struct *work) if (cxl_cper_prot_err_work != work) return -EINVAL; - guard(spinlock)(&cxl_cper_prot_err_work_lock); + guard(spinlock_irqsave)(&cxl_cper_prot_err_work_lock); cxl_cper_prot_err_work = NULL; return 0; } @@ -852,7 +852,7 @@ int cxl_cper_register_work(struct work_struct *work) if (cxl_cper_work) return -EINVAL; - guard(spinlock)(&cxl_cper_work_lock); + guard(spinlock_irqsave)(&cxl_cper_work_lock); cxl_cper_work = work; return 0; } @@ -863,7 +863,7 @@ int cxl_cper_unregister_work(struct work_struct *work) if (cxl_cper_work != work) return -EINVAL; - guard(spinlock)(&cxl_cper_work_lock); + guard(spinlock_irqsave)(&cxl_cper_work_lock); cxl_cper_work = NULL; return 0; } -- 2.54.0