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 71A5B3F54D1; Fri, 17 Jul 2026 16:16:58 +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=1784305020; cv=none; b=MFeIAMOtGYsSTiPN5b8eE66Ba2e9IpaeItgLuDLoIJkjcWyiHOyUp6bdOppuPcb8Ri0j8OJh3ZoKmHcurNAleqNziAtXOSw7KNnDqJhg5hZr5yNc7udL84xyyp0Lpm4p9r0KdvKsa2s52lZBvMD1VdCnwrTybcqH03406ylArIY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784305020; c=relaxed/simple; bh=4JjeIpxBlZ+GPpVcSFG1ZahrnkRPBqsc8j77dwfAtYo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EILGf4pJbuYihQvGaB2J2dJBtygcOZdDI7k4k7IJDkYxOIOPqfuNMHdeV4Rk21pvO7eIHXTPXoWBzNdFki4Km8sYTImhk3yourGyP/0t3h/mA0exZ/advn3QNUD7XTNFgSZD6msbdX4sQfPNUzShbVibNzIShagiU7ILpIlj9Q4= 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 411461F000E9; Fri, 17 Jul 2026 16:16:58 +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, terry.bowman@amd.com, sashiko-bot@kernel.org Subject: [PATCH v3 06/10] ACPI: extlog: Defer CXL protocol error handling to avoid lock inversion Date: Fri, 17 Jul 2026 09:16:43 -0700 Message-ID: <20260717161647.1493259-7-dave.jiang@intel.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260717161647.1493259-1-dave.jiang@intel.com> References: <20260717161647.1493259-1-dave.jiang@intel.com> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit sashiko-bot flagged an AB-BA deadlock between the PCI device_lock and the MCE decoder chain rwsem. extlog_print() calls cxl_cper_handle_prot_err() synchronously while the MCE notifier chain rwsem is held, and that path takes the PCI device_lock via guard(device)(). The probe path takes the locks in the opposite order (device_lock held while mce_register_decode_chain() takes the rwsem), so the two form an AB-BA deadlock. ghes.c already avoids this by posting protocol errors to a kfifo and handling them from a workqueue via cxl_cper_post_prot_err(). Export that function and use it from acpi_extlog.c instead of calling cxl_cper_handle_prot_err() directly. Reported-by: sashiko-bot@kernel.org Link: https://lore.kernel.org/linux-cxl/20260709165457.8BA181F000E9@smtp.kernel.org/ Assisted-by: Claude:claude-sonnet-4-6 Signed-off-by: Dave Jiang --- drivers/acpi/acpi_extlog.c | 23 +++-------------------- drivers/acpi/apei/ghes.c | 5 +++-- include/acpi/ghes.h | 4 ++++ 3 files changed, 10 insertions(+), 22 deletions(-) diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c index 0c440d75d9a7..ae79d090de33 100644 --- a/drivers/acpi/acpi_extlog.c +++ b/drivers/acpi/acpi_extlog.c @@ -172,23 +172,6 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err, #endif } -static void -extlog_cxl_cper_handle_prot_err(struct cxl_cper_sec_prot_err *prot_err, - int severity, u32 len) -{ -#ifdef ACPI_APEI_PCIEAER - struct cxl_cper_prot_err_work_data wd; - - if (cxl_cper_sec_prot_err_valid(prot_err, len)) - return; - - if (cxl_cper_setup_prot_err_work_data(&wd, prot_err, severity)) - return; - - cxl_cper_handle_prot_err(&wd); -#endif -} - static int extlog_print(struct notifier_block *nb, unsigned long val, void *data) { @@ -244,9 +227,9 @@ static int extlog_print(struct notifier_block *nb, unsigned long val, struct cxl_cper_sec_prot_err *prot_err = acpi_hest_get_payload(gdata); - extlog_cxl_cper_handle_prot_err(prot_err, - gdata->error_severity, - gdata->error_data_length); + cxl_cper_post_prot_err(prot_err, + gdata->error_severity, + gdata->error_data_length); } else if (guid_equal(sec_type, &CPER_SEC_PCIE)) { struct cper_sec_pcie *pcie_err = acpi_hest_get_payload(gdata); diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 17e4ef555292..b8dbd99da47e 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -752,8 +752,8 @@ static DEFINE_KFIFO(cxl_cper_prot_err_fifo, struct cxl_cper_prot_err_work_data, static DEFINE_SPINLOCK(cxl_cper_prot_err_work_lock); struct work_struct *cxl_cper_prot_err_work; -static void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err, - int severity, u32 len) +void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err, + int severity, u32 len) { #ifdef CONFIG_ACPI_APEI_PCIEAER struct cxl_cper_prot_err_work_data wd; @@ -777,6 +777,7 @@ static void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err, schedule_work(cxl_cper_prot_err_work); #endif } +EXPORT_SYMBOL_FOR_MODULES(cxl_cper_post_prot_err, "acpi_extlog"); int cxl_cper_register_prot_err_work(struct work_struct *work) { diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h index 8d7e5caef3f1..4dcbb2c30ea2 100644 --- a/include/acpi/ghes.h +++ b/include/acpi/ghes.h @@ -143,4 +143,8 @@ static inline int ghes_notify_sea(void) { return -ENOENT; } struct notifier_block; extern void ghes_register_report_chain(struct notifier_block *nb); extern void ghes_unregister_report_chain(struct notifier_block *nb); + +struct cxl_cper_sec_prot_err; +void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err, + int severity, u32 len); #endif /* GHES_H */ -- 2.55.0