From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f170.google.com (mail-pg1-f170.google.com [209.85.215.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 536FA38838F for ; Mon, 24 Aug 2026 09:30:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787563805; cv=none; b=UqFP4xCDYtXxuFNNxPyvvSfR4MrKxJMrtiAzESRZznCGy+1F/i6JSwWwScnFGhT/N59qzMmI7NtY/mXakWFC5RBe7xE1M6sxv7g3wng7DU112fClA7Bz8j3iVLsnZYhIc5Z/Zb792pBguCFyqTsgOCdruBCSLCTBQ+wTMAZ06tg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787563805; c=relaxed/simple; bh=B3PrhrTJv6So4f7GRIVWNL1Mx+SV1o4fVI1hxjaQD1M=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=M+H/VnAtNAWKHqYMYctK9JsM/2UdqXNmplmIqGVk4qWyb9wIGvVipWDw72YHDS7oqi1v4IFuiv0gDu/JThegkqFf86sBcxtQcwLSPQtgis5xoZucleB1Ii92XDnr3K5j+2f7Xnyg6zziDGFJswRlpfGtzVXjxuviP/1FZg+rb4o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=pCxHA3hi; arc=none smtp.client-ip=209.85.215.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="pCxHA3hi" Received: by mail-pg1-f170.google.com with SMTP id 41be03b00d2f7-ca7c1176317so2712781a12.1 for ; Mon, 24 Aug 2026 02:30:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787563803; x=1788168603; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=DGZ9Z1DPfEdVHcTUddQdNEyq05aFRAjwLdFGsMJBr5c=; b=pCxHA3hiwA/c+rwennz4/pXnULowwmaDIPjhwIMdxdwOTlhbm/tWYuaHSUL3xp6aZN xmiY/PX1/72mZaOoRsBulhpNBvr21bV0UsaIBNH6YM0zFwFIFp2pudVOhj28mUE7Rys0 XJbqhHtcZ1zsopsm96/EvhwdTBLHYUdO0LQbZ8aUEMUnllhS3MUTRo1f6LTk8d+Yxq5e em59F8BlL17odWKsba2ux2LFuJS2mArm2Km336QFormaON43Xj8qxl5QDVcUkcIAhj80 EqcEjbNFXHJ2w1KnkD16VtvlEj14XK9YSY07T/mtMC4O6Jm2dgE0QCXk4fT0ftBDhk2A 9vGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787563803; x=1788168603; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=DGZ9Z1DPfEdVHcTUddQdNEyq05aFRAjwLdFGsMJBr5c=; b=O7eKJjx/N2GyRE0pv4f/KVgRBawfR83Vkh7mTwenInqIcrKJFnJfDuvumqUFl1c98b nUcwifOTHrsKyqzqef+OEkaWJ6j1d3FfUpLvg/1Yuuq8sG4V4OCJ9wGmCmGmBxhB3/Zr YxE18cu3QGOeBtA1SVl50KQy8f0OegoaFC3aRBIreicDOrbTt1IaXJELGbHe5Ssw+swM STz5qpCKoZGxiPnMzQqaZqt9L1/S9ICIxYJ7rbPXGodZLHoQkvZpJVWE+DGmsll/mZbD OIHhomhUBFVGHItMYSdC+KYyrfL5PWS4+9901WFSqsu7lAAr9QGmjyJn+Og5og3B84O6 wUYQ== X-Forwarded-Encrypted: i=1; AHgh+RoCss1O5pLex1WpT7OmlfdZbDbL1OoWMABH13JipvDyX7Ulnq0KZE42xgKjLrO29UyD+qFCVqPuihr+vPg=@vger.kernel.org X-Gm-Message-State: AFuF++kJwpKaPyJu/afSFTVgwm3apprPO2v1ZPLWc0XHkNMeX5ujgX03 QPWXKxH4NeFwFmi6R8NCbbcXUuresL3lEfVJ2515+xRgrIhlGX6jw3WI X-Gm-Gg: AR+sD13c8jwfPrtMYywUw6RQXiKhDRV5i16EN7pzaTImLQt8Cp2HK+tD8f1RL1jmDuj Kk0SP8Qkkhy66wqyzK9FyZaMSeO/PuZECEYA6HO/qNzgqRnWmz4LBtSksqtrRdY0aNYTJOuPFxC ElDQN0H4/PkDW7Qk1PU9LfAgU2VqTGCvIvLQBFQM2CGEfLx6/3oItd87A4wyTDN8Fry8DUM9jin wlmtcruDUaTim00/Rwgz3oIvBEZK7vaXkmkL2FRm/tXWA0d06/6QxIv+1N41xI/lPyJpYFPwSSD GKZ63u0EI+wN3xU6Bdhw1DFI7YQ5q8mrwS5euRITXcEmOw51bHSjanK9n5yXNpjyaJXaSlHsDr6 sPuEhpsBHrdxTNZezSvc9w1FGLDOsX+FKNfqJQfggHv2cTcXm5I9uqaAHzdfiU5r3yJJJ3I/V2F 9XgRUscmpul8fytIs3YZ809OT/Lr4DSvf4fG5aX28LwwOrKWbRa19vOPs78C0tzuKSlg+h3F281 bA= X-Received: by 2002:a05:6a21:d89:b0:3cc:f008:8125 with SMTP id adf61e73a8af0-3cd4b9a9fabmr34624401637.1.1787563802568; Mon, 24 Aug 2026 02:30:02 -0700 (PDT) Received: from localhost.localdomain ([240e:b8f:1df9:a600:c693:b19f:ada0:748]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cc199e60035sm845226a12.22.2026.08.24.02.29.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Aug 2026 02:30:02 -0700 (PDT) From: Vernon Yang To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org Cc: nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, zokeefe@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, Vernon Yang Subject: [PATCH v3 0/3] mm: khugepaged: fix tracepoint UAF Date: Mon, 24 Aug 2026 17:29:32 +0800 Message-ID: <20260824092935.73892-1-vernon2gm@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Vernon Yang The khugepaged tracepoints take a folio pointer and call folio_pfn(), but by then the folio may no longer be valid: freed after folio_put(), folio_unlock() or pte_unmap_unlock(), or not a folio at all but an xarray-encoded swap entry. On classic SPARSEMEM, dereferencing it oopses khugepaged as soon as the trace event is enabled; on other memory models it merely prints a bogus pfn. Pass the pfn to the tracepoints directly, captured while the folio is still pinned, closing the use-after-free windows in mm_khugepaged_scan_file(), mm_khugepaged_scan_pmd() and mm_khugepaged_collapse_file(). This series is based on mm-new. V2 -> V3: - Place folio_pfn() inside the xas_for_each() loop in PATCH#1. - Already defaulted the pfn value to -1, to simple it in PATCH#2. V1 -> V2: - Instead of passing the folio, just pass the pfn directly. - Using the folio_pfn() before dropping the reference or the page table lock. V2 : https://lore.kernel.org/linux-mm/20260815051924.194810-1-vernon2gm@gmail.com/ V1 : https://lore.kernel.org/linux-mm/20260811133655.267739-1-vernon2gm@gmail.com/ Vernon Yang (3): mm: khugepaged: fix swap entry value to folio_pfn() mm: khugepaged: fix folio is used after pte_unmap_unlock() mm: khugepaged: fix folio is used after folio_put/unlock() include/trace/events/huge_memory.h | 18 +++++++++--------- mm/khugepaged.c | 15 ++++++++++++--- 2 files changed, 21 insertions(+), 12 deletions(-) base-commit: a032d41a86cb82a747bc14d9c82b3e153a9a9ab7 -- 2.53.0