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 3925D39C636 for ; Mon, 20 Jul 2026 13:41:37 +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=1784554901; cv=none; b=WSKoY5JXxk1NO9f1VQXq9rfjaRSz6+x4PVY+E9sXK7nOjgw5oWCz5dJxvf4QMUHZC1n1QnYHtbRKewzq+gMS1Ys00kDCMCcgRtqxREXAnL6tBGYQQa/eLLU2eQsXOEiTJKZaLEzsJ3hdmGtx+t41C/aE2wLLD18pnRh2VS31kbQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784554901; c=relaxed/simple; bh=QhoDBxgHN6RKWVYsjjKCAtBNNEIB+AO5/Unp9t/fgHc=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=qcZbiY5aVWANEWHuqFJLpqabAe4qw8uduDgK3R51X1YaeEtoLTJQuwgszqXy3/NLogjCcZ//vtO3yI/HvlpSyZ4peo2hyw+TOD0cspaaWxnV8Hi97P67dYZb4PEJf8fh9AS633xGqL8DAN9AZTDYZTc1+twa3e7fNFDkbcWo2UI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iq2kgt2S; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="iq2kgt2S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 061631F00A3A; Mon, 20 Jul 2026 13:41:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784554897; bh=0zdloegciNubZEHNzvacovxt0rRbXOeUU6Sm6IDaErI=; h=Subject:To:Cc:From:Date; b=iq2kgt2Sm5nOlib/cmTyCJiY0YnYzQVhOfGuqpHf/v8GMJj6Z2+Mu3rQI4w0NJNdk Ya48mJyNOVwiIjanHxqKJzzaQs9gfTPsMfyFT49VhkkJVy+2aCIbCJIh19m/Fd9NKS VPT3XJE/D6sJ1mB6qN7gnUlPTtgSQzRyovPq9rhQ= Subject: FAILED: patch "[PATCH] cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size" failed to apply to 6.18-stable tree To: terry.bowman@amd.com,alison.schofield@intel.com,benjamin.cheatham@amd.com,dave.jiang@intel.com,icheng@nvidia.com Cc: From: Date: Mon, 20 Jul 2026 15:41:28 +0200 Message-ID: <2026072028-shaky-author-b5df@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y git checkout FETCH_HEAD git cherry-pick -x c268f949e219f9e179558e836f457f6c5fbec416 # git commit -s git send-email --to '' --in-reply-to '2026072028-shaky-author-b5df@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From c268f949e219f9e179558e836f457f6c5fbec416 Mon Sep 17 00:00:00 2001 From: Terry Bowman Date: Fri, 5 Jun 2026 13:06:10 -0500 Subject: [PATCH] cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size The CXL r4.0 8.2.4.17.7 RAS Capability Structure has total length 0x58 bytes (CXL_RAS_CAPABILITY_LENGTH); the Header Log occupies the trailing 64 bytes at offset 0x18. CXL_HEADERLOG_SIZE was defined as SZ_512, eight times the actual on-device size. header_log_copy() reads CXL_HEADERLOG_SIZE_U32 (128) dwords from the RAS capability iomap, overrunning the 88-byte mapping by 448 bytes. The cxl_aer_uncorrectable_error trace event memcpy()s CXL_HEADERLOG_SIZE (512) bytes from its source. For the CPER caller the source is struct cxl_ras_capability_regs::header_log[16] (64 bytes) embedded in a stack-local cxl_cper_prot_err_work_data, so the memcpy reads 448 bytes of kernel stack into the trace event ring buffer where userspace can read it via tracefs. Set CXL_HEADERLOG_SIZE to 64 and derive CXL_HEADERLOG_SIZE_U32 from it, bringing all iomap readers into agreement on 16 dwords. Userspace tools such as rasdaemon have grown a dependency on the buggy 512-byte (128 u32) header_log layout in the cxl_aer_uncorrectable_error trace event. Add CXL_HEADERLOG_TRACE_SIZE_U32 = 128 and use it for the trace event __array and its memcpy to preserve that ABI. Both callers now pass a zero-filled u32[CXL_HEADERLOG_TRACE_SIZE_U32] staging buffer with only the first CXL_HEADERLOG_SIZE_U32 (16) entries populated from hardware; the remaining 112 u32s are zero-padded, keeping the 512-byte trace ring buffer layout intact. [ dj: Replaced 64 with SZ_64 per RichardC ] Fixes: 36f257e3b0ba ("acpi/ghes, cxl/pci: Process CXL CPER Protocol Errors") Fixes: 2905cb5236cb ("cxl/pci: Add (hopeful) error handling support") Cc: stable@vger.kernel.org Reported-by: Sashiko Signed-off-by: Terry Bowman Reviewed-by: Alison Schofield Reviewed-by: Dave Jiang Reviewed-by: Ben Cheatham Reviewed-by: Richard Cheng Link: https://patch.msgid.link/20260605180610.2249458-1-terry.bowman@amd.com Signed-off-by: Dave Jiang diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c index 006c6ffc2f56..99fb00949c2f 100644 --- a/drivers/cxl/core/ras.c +++ b/drivers/cxl/core/ras.c @@ -8,6 +8,10 @@ #include #include "trace.h" +/* Check that UCE header definition is maintained to keep ABI intact */ +static_assert(CXL_HEADERLOG_TRACE_SIZE_U32 == 128, + "rasdaemon ABI requires exactly 128 u32s"); + static void cxl_cper_trace_corr_port_prot_err(struct pci_dev *pdev, struct cxl_ras_capability_regs ras_cap) { @@ -19,6 +23,7 @@ static void cxl_cper_trace_corr_port_prot_err(struct pci_dev *pdev, static void cxl_cper_trace_uncorr_port_prot_err(struct pci_dev *pdev, struct cxl_ras_capability_regs ras_cap) { + u32 hl[CXL_HEADERLOG_TRACE_SIZE_U32] = {}; u32 status = ras_cap.uncor_status & ~ras_cap.uncor_mask; u32 fe; @@ -28,8 +33,8 @@ static void cxl_cper_trace_uncorr_port_prot_err(struct pci_dev *pdev, else fe = status; - trace_cxl_port_aer_uncorrectable_error(&pdev->dev, status, fe, - ras_cap.header_log); + memcpy(hl, ras_cap.header_log, CXL_HEADERLOG_SIZE); + trace_cxl_port_aer_uncorrectable_error(&pdev->dev, status, fe, hl); } static void cxl_cper_trace_corr_prot_err(struct cxl_memdev *cxlmd, @@ -44,6 +49,7 @@ static void cxl_cper_trace_uncorr_prot_err(struct cxl_memdev *cxlmd, struct cxl_ras_capability_regs ras_cap) { + u32 hl[CXL_HEADERLOG_TRACE_SIZE_U32] = {}; u32 status = ras_cap.uncor_status & ~ras_cap.uncor_mask; u32 fe; @@ -53,8 +59,15 @@ cxl_cper_trace_uncorr_prot_err(struct cxl_memdev *cxlmd, else fe = status; - trace_cxl_aer_uncorrectable_error(cxlmd, status, fe, - ras_cap.header_log); + /* + * ras_cap.header_log[] holds CXL_HEADERLOG_SIZE_U32 (16) hardware + * dwords. Copy them into the front of a zero-filled + * CXL_HEADERLOG_TRACE_SIZE_U32 (128) u32 staging buffer so the trace + * event memcpy sees a full 512-byte source and the userspace ABI + * (rasdaemon) is preserved. + */ + memcpy(hl, ras_cap.header_log, CXL_HEADERLOG_SIZE); + trace_cxl_aer_uncorrectable_error(cxlmd, status, fe, hl); } static int match_memdev_by_parent(struct device *dev, const void *uport) @@ -204,12 +217,12 @@ static void header_log_copy(void __iomem *ras_base, u32 *log) { void __iomem *addr; u32 *log_addr; - int i, log_u32_size = CXL_HEADERLOG_SIZE / sizeof(u32); + int i; addr = ras_base + CXL_RAS_HEADER_LOG_OFFSET; log_addr = log; - for (i = 0; i < log_u32_size; i++) { + for (i = 0; i < CXL_HEADERLOG_SIZE_U32; i++) { *log_addr = readl(addr); log_addr++; addr += sizeof(u32); @@ -222,7 +235,7 @@ static void header_log_copy(void __iomem *ras_base, u32 *log) */ bool cxl_handle_ras(struct device *dev, void __iomem *ras_base) { - u32 hl[CXL_HEADERLOG_SIZE_U32]; + u32 hl[CXL_HEADERLOG_TRACE_SIZE_U32] = {}; void __iomem *addr; u32 status; u32 fe; diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h index a972e4ef1936..d37876096dd7 100644 --- a/drivers/cxl/core/trace.h +++ b/drivers/cxl/core/trace.h @@ -56,7 +56,7 @@ TRACE_EVENT(cxl_port_aer_uncorrectable_error, __string(host, dev_name(dev->parent)) __field(u32, status) __field(u32, first_error) - __array(u32, header_log, CXL_HEADERLOG_SIZE_U32) + __array(u32, header_log, CXL_HEADERLOG_TRACE_SIZE_U32) ), TP_fast_assign( __assign_str(device); @@ -64,10 +64,14 @@ TRACE_EVENT(cxl_port_aer_uncorrectable_error, __entry->status = status; __entry->first_error = fe; /* - * Embed the 512B headerlog data for user app retrieval and - * parsing, but no need to print this in the trace buffer. + * Embed headerlog data for user app retrieval and parsing, + * but no need to print in the trace buffer. Only + * CXL_HEADERLOG_SIZE_U32 (16) dwords are hardware data; + * the remaining entries preserve the 512-byte ABI layout + * rasdaemon depends on and are zero-filled by the caller. */ - memcpy(__entry->header_log, hl, CXL_HEADERLOG_SIZE); + memcpy(__entry->header_log, hl, + CXL_HEADERLOG_TRACE_SIZE_U32 * sizeof(u32)); ), TP_printk("device=%s host=%s status: '%s' first_error: '%s'", __get_str(device), __get_str(host), @@ -85,7 +89,7 @@ TRACE_EVENT(cxl_aer_uncorrectable_error, __field(u64, serial) __field(u32, status) __field(u32, first_error) - __array(u32, header_log, CXL_HEADERLOG_SIZE_U32) + __array(u32, header_log, CXL_HEADERLOG_TRACE_SIZE_U32) ), TP_fast_assign( __assign_str(memdev); @@ -94,10 +98,14 @@ TRACE_EVENT(cxl_aer_uncorrectable_error, __entry->status = status; __entry->first_error = fe; /* - * Embed the 512B headerlog data for user app retrieval and - * parsing, but no need to print this in the trace buffer. + * Embed headerlog data for user app retrieval and parsing, + * but no need to print in the trace buffer. Only + * CXL_HEADERLOG_SIZE_U32 (16) dwords are hardware data; + * the remaining entries preserve the 512-byte ABI layout + * rasdaemon depends on and are zero-filled by the caller. */ - memcpy(__entry->header_log, hl, CXL_HEADERLOG_SIZE); + memcpy(__entry->header_log, hl, + CXL_HEADERLOG_TRACE_SIZE_U32 * sizeof(u32)); ), TP_printk("memdev=%s host=%s serial=%lld: status: '%s' first_error: '%s'", __get_str(memdev), __get_str(host), __entry->serial, diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 1297594beaec..21fc89d3aeea 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -158,8 +158,18 @@ static inline int ways_to_eiw(unsigned int ways, u8 *eiw) #define CXL_RAS_CAP_CONTROL_FE_MASK GENMASK(5, 0) #define CXL_RAS_HEADER_LOG_OFFSET 0x18 #define CXL_RAS_CAPABILITY_LENGTH 0x58 -#define CXL_HEADERLOG_SIZE SZ_512 -#define CXL_HEADERLOG_SIZE_U32 SZ_512 / sizeof(u32) +#define CXL_HEADERLOG_SIZE SZ_64 +#define CXL_HEADERLOG_SIZE_U32 (CXL_HEADERLOG_SIZE / sizeof(u32)) + +/* + * The RAS UCE trace event header array was originally sized at SZ_512/sizeof(u32) + * = 128 u32s due to a bug. Userspace tools (rasdaemon) have grown a dependency + * on that 512-byte layout. Keep the trace array at 128 u32s to preserve the + * ABI; only CXL_HEADERLOG_SIZE_U32 (16) dwords are valid hardware data, the + * remainder are zero-filled. + */ +#define CXL_HEADERLOG_TRACE_SIZE SZ_512 +#define CXL_HEADERLOG_TRACE_SIZE_U32 (CXL_HEADERLOG_TRACE_SIZE / sizeof(u32)) /* CXL 2.0 8.2.8.1 Device Capabilities Array Register */ #define CXLDEV_CAP_ARRAY_OFFSET 0x0