From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EF69C3ABB2 for ; Wed, 28 May 2025 09:16:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9B51C6B0095; Wed, 28 May 2025 05:16:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 966446B0096; Wed, 28 May 2025 05:16:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 87C296B0098; Wed, 28 May 2025 05:16:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 68AE96B0095 for ; Wed, 28 May 2025 05:16:21 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 133F3C06D0 for ; Wed, 28 May 2025 09:16:21 +0000 (UTC) X-FDA: 83491760562.12.787939D Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) by imf18.hostedemail.com (Postfix) with ESMTP id 53DB71C0005 for ; Wed, 28 May 2025 09:16:19 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=nvHJMyo4; spf=pass (imf18.hostedemail.com: domain of ye.liu@linux.dev designates 95.215.58.174 as permitted sender) smtp.mailfrom=ye.liu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1748423779; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=Re+0CfHFPp2+XEq5Eas2GB9V8vWyFYXfz2FQ+a6YE58=; b=GBvuHSKIEfirGFcRcyR9G/H+FOcemj3Bqp3VX54to3SNU+FEx+Xyofl+rkewxFrh5les8/ b1jwjYEDMnbZpSx61W6HMmLHDD4x0Fwt8Dvgk30FIpzPHTXu4sfPo4UBcgMegPWS6AU7N7 h0igsHlOiLVdVB4Lrugq+eFmJe9FaAY= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=nvHJMyo4; spf=pass (imf18.hostedemail.com: domain of ye.liu@linux.dev designates 95.215.58.174 as permitted sender) smtp.mailfrom=ye.liu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1748423779; a=rsa-sha256; cv=none; b=wQ9sYB3PsBQcTJJJubw1itw2PjnpzT3GM6yVm4nyi+SpNpvSEvM+vpdUWiPrT/AjSmFd5f 7OysE08CvOezDoqH/v4UiNxDVEVWDPFm8dhF7REHTZCZF6lbDLJQp2RLOhKKlvkSk24zED 9GLbd46xdDgGbsiFRHVz04tJLYSPJGk= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1748423776; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=Re+0CfHFPp2+XEq5Eas2GB9V8vWyFYXfz2FQ+a6YE58=; b=nvHJMyo43wymkPFRmv4HWt/fOCHgseR+XsxmVgRVGRQg7J/UXcabhdvI31jeyPMQ4QjFrF 00DfZ4QD4aB2xdJ8OSQ1n1WT7xFbZVUxS8ZUN7ZSSYzGZxHyfypyAxYzkgl//I+cEe2VBF dlT4QBmRvemQv6M1NfwKy1sd69Z6JFM= From: Ye Liu To: akpm@linux-foundation.org Cc: linux-debuggers@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-toolchains@vger.kernel.org, osandov@osandov.com, paulmck@kernel.org, sweettea-kernel@dorminy.me, liuye@kylinos.cn, ye.liu@linux.dev, fweimer@redhat.com, sj@kernel.org Subject: [PATCH v4] tools/mm: Add script to display page state for a given PID and VADDR Date: Wed, 28 May 2025 17:15:43 +0800 Message-Id: <20250528091543.355386-1-ye.liu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 53DB71C0005 X-Stat-Signature: nhbxzb97abzfhqkyh1nrmbnin68tntcq X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1748423779-997158 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Ye Liu Introduces a new drgn script, `show_page_info.py`, which allows users to analyze the state of a page given a process ID (PID) and a virtual address (VADDR). This can help kernel developers or debuggers easily inspect page-related information in a live kernel or vmcore. The script extracts information such as the page flags, mapping, and other metadata relevant to diagnosing memory issues. Output example: sudo ./show_page_info.py 1 0x7fb3eb1b2000 PID: 1 Comm: systemd mm: 0xffff8d27279f9cc0 Raw: 0017ffffc000416c fffff31105a61b08 fffff31105a63608 ffff8d27121326a8 Raw: 0000000000000000 ffff8d271b9dcc40 0000002500000007 ffff8d2711f12700 User Virtual Address: 0x7fb3eb1b2000 Page Address: 0xfffff31106356a00 Page Flags: PG_referenced|PG_uptodate|PG_lru|PG_head|PG_active| PG_private|PG_reported|PG_has_hwpoisoned Page Size: 4096 Page PFN: 0x18d5a8 Page Physical: 0x18d5a8000 Page Virtual: 0xffff8d274d5a8000 Page Refcount: 37 Page Mapcount: 7 Page Index: 0x0 Page Memcg Data: 0xffff8d2711f12700 Memcg Name: init.scope Memcg Path: /sys/fs/cgroup/memory/init.scope Page Mapping: 0xffff8d27121326a8 Page Anon/File: File Page VMA: 0xffff8d26cac47600 VMA Start: 0x7fb3eb1b2000 VMA End: 0x7fb3eb1b6000 This page is part of a compound page. This page is the head page of a compound page. Head Page: 0xfffff31106356a00 Compound Order: 2 Number of Pages: 4 Signed-off-by: Ye Liu Changes in v4: - Add error and exception handling. - Adjust the way to obtain PAGE_SIZE. - Fix the acquisition of memcg. - Link to v3:https://lore.kernel.org/all/20250423014850.344501-1-ye.liu@linux.dev/ Changes in v3: - Adjust display style. - Link to v2:https://lore.kernel.org/all/20250421080748.114750-1-ye.liu@linux.dev/ Changes in v2: - Move the show_page_info.py file to tools/mm. - Link to v1: https://lore.kernel.org/all/20250415075024.248232-1-ye.liu@linux.dev/ --- MAINTAINERS | 5 ++ tools/mm/show_page_info.py | 152 +++++++++++++++++++++++++++++++++++++ 2 files changed, 157 insertions(+) create mode 100755 tools/mm/show_page_info.py diff --git a/MAINTAINERS b/MAINTAINERS index 0cb9e55021cb..3cbd46bf1eab 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18726,6 +18726,11 @@ F: Documentation/mm/page_table_check.rst F: include/linux/page_table_check.h F: mm/page_table_check.c +PAGE STATE DEBUG SCRIPT +M: Ye Liu +S: Maintained +F: tools/mm/show_page_info.py + PANASONIC LAPTOP ACPI EXTRAS DRIVER M: Kenneth Chan L: platform-driver-x86@vger.kernel.org diff --git a/tools/mm/show_page_info.py b/tools/mm/show_page_info.py new file mode 100755 index 000000000000..5c46501e24f4 --- /dev/null +++ b/tools/mm/show_page_info.py @@ -0,0 +1,152 @@ +#!/usr/bin/env drgn +# SPDX-License-Identifier: GPL-2.0-only +# Copyright (C) 2025 Ye Liu + +import argparse +from drgn import Object, FaultError +from drgn.helpers.linux import find_task, follow_page, page_size +from drgn.helpers.linux.mm import ( + decode_page_flags, page_to_pfn, page_to_phys, page_to_virt, vma_find, + PageSlab, PageCompound, PageHead, PageTail, compound_head, compound_order, compound_nr +) +from drgn.helpers.linux.cgroup import cgroup_name, cgroup_path + +DESC = """ +This is a drgn script to show the page state. +For more info on drgn, visit https://github.com/osandov/drgn. +""" + +MEMCG_DATA_OBJEXTS = 1 << 0 +MEMCG_DATA_KMEM = 1 << 1 +__NR_MEMCG_DATA_FLAGS = 1 << 2 + +def format_page_data(data): + """Format raw page data into a readable hex dump.""" + try: + chunks = [data[i:i+8] for i in range(0, len(data), 8)] + hex_chunks = ["".join(f"{b:02x}" for b in chunk[::-1]) for chunk in chunks] + lines = [" ".join(hex_chunks[i:i+4]) for i in range(0, len(hex_chunks), 4)] + return "\n".join(f"Raw: {line}" for line in lines) + except Exception as e: + return f"Error formatting page data: {e}" + +def get_memcg_info(page): + """Retrieve memory cgroup information for a page.""" + try: + memcg_data = page.memcg_data.value_() + if memcg_data & MEMCG_DATA_OBJEXTS: + slabobj_ext = Object(prog, "struct slabobj_ext *", address=memcg_data & ~(__NR_MEMCG_DATA_FLAGS - 1)) + memcg_value = slabobj_ext.objcg.memcg.value_() + elif memcg_data & MEMCG_DATA_KMEM: + objcg = Object(prog, "struct obj_cgroup *", address=memcg_data & ~(__NR_MEMCG_DATA_FLAGS - 1)) + memcg_value = objcg.memcg.value_() + else: + memcg_value = memcg_data & ~(__NR_MEMCG_DATA_FLAGS - 1) + + if memcg_value == 0: + return "none", "/sys/fs/cgroup/memory/" + + memcg = Object(prog, "struct mem_cgroup *", address=memcg_value) + cgrp = memcg.css.cgroup + return cgroup_name(cgrp).decode(), f"/sys/fs/cgroup/memory{cgroup_path(cgrp).decode()}" + except FaultError as e: + return "unknown", f"Error retrieving memcg info: {e}" + except Exception as e: + return "unknown", f"Unexpected error: {e}" + +def show_page_state(page, addr, mm, pid, task): + """Display detailed information about a page.""" + try: + print(f'PID: {pid} Comm: {task.comm.string_().decode()} mm: {hex(mm)}') + try: + print(format_page_data(prog.read(page.value_(), 64))) + except FaultError as e: + print(f"Error reading page data: {e}") + + fields = { + "User Virtual Address": hex(addr), + "Page Address": hex(page.value_()), + "Page Flags": decode_page_flags(page), + "Page Size": prog["PAGE_SIZE"].value_(), + "Page PFN": hex(page_to_pfn(page).value_()), + "Page Physical": hex(page_to_phys(page).value_()), + "Page Virtual": hex(page_to_virt(page).value_()), + "Page Refcount": page._refcount.counter.value_(), + "Page Mapcount": page._mapcount.counter.value_(), + "Page Index": hex(page.__folio_index.value_()), + "Page Memcg Data": hex(page.memcg_data.value_()), + } + + memcg_name, memcg_path = get_memcg_info(page) + fields["Memcg Name"] = memcg_name + fields["Memcg Path"] = memcg_path + fields["Page Mapping"] = hex(page.mapping.value_()) + fields["Page Anon/File"] = "Anon" if page.mapping.value_() & 0x1 else "File" + + try: + vma = vma_find(mm, addr) + fields["Page VMA"] = hex(vma.value_()) + fields["VMA Start"] = hex(vma.vm_start.value_()) + fields["VMA End"] = hex(vma.vm_end.value_()) + except FaultError as e: + fields["Page VMA"] = "Unavailable" + fields["VMA Start"] = "Unavailable" + fields["VMA End"] = "Unavailable" + print(f"Error retrieving VMA information: {e}") + + # Calculate the maximum field name length for alignment + max_field_len = max(len(field) for field in fields) + + # Print aligned fields + for field, value in fields.items(): + print(f"{field}:".ljust(max_field_len + 2) + f"{value}") + + # Additional information about the page + if PageSlab(page): + print("This page belongs to the slab allocator.") + + if PageCompound(page): + print("This page is part of a compound page.") + if PageHead(page): + print("This page is the head page of a compound page.") + if PageTail(page): + print("This page is the tail page of a compound page.") + print(f"{'Head Page:'.ljust(max_field_len + 2)}{hex(compound_head(page).value_())}") + print(f"{'Compound Order:'.ljust(max_field_len + 2)}{compound_order(page).value_()}") + print(f"{'Number of Pages:'.ljust(max_field_len + 2)}{compound_nr(page).value_()}") + else: + print("This page is not part of a compound page.") + except FaultError as e: + print(f"Error accessing page state: {e}") + except Exception as e: + print(f"Unexpected error: {e}") + +def main(): + """Main function to parse arguments and display page state.""" + parser = argparse.ArgumentParser(description=DESC, formatter_class=argparse.RawTextHelpFormatter) + parser.add_argument('pid', metavar='PID', type=int, help='Target process ID (PID)') + parser.add_argument('vaddr', metavar='VADDR', type=str, help='Target virtual address in hexadecimal format (e.g., 0x7fff1234abcd)') + args = parser.parse_args() + + try: + vaddr = int(args.vaddr, 16) + except ValueError: + print(f"Error: Invalid virtual address format: {args.vaddr}") + return + + try: + task = find_task(args.pid) + mm = task.mm + page = follow_page(mm, vaddr) + + if page: + show_page_state(page, vaddr, mm, args.pid, task) + else: + print(f"Address {hex(vaddr)} is not mapped.") + except FaultError as e: + print(f"Error accessing task or memory: {e}") + except Exception as e: + print(f"Unexpected error: {e}") + +if __name__ == "__main__": + main() -- 2.25.1