From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f175.google.com (mail-pl1-f175.google.com [209.85.214.175]) (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 047BE1C84AB for ; Sat, 15 Aug 2026 05:19:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786771201; cv=none; b=KIloH4CC1KotYDSvM9y1z6JtYzdWeM0kRQRGBjBbj5e/obBCWVolsM0kK90UuKo755venc7Abz6EDoi6JYRzC3xQKLlXhH3j0wB5CLcitXLZfGhCPAZ9aUqp1yEKMXa5W3f4kDLENVmqNW3aD5DJPyqfLtRhR8g9UNJAiou49JA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786771201; c=relaxed/simple; bh=LO7Nv2odxpc7nFBv6KRlb6OBFDlZMZWjFWWN3JpMc1w=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=JZgXI5J41Npjw6x8djHfU1S1hdICekcG6YbYIXQKXm67VF7mUgEU2CWrhbEv34dNCjOXIkNYPwAefkufY2HfVQjaOXkSitIU1i13HyuxBnxX9pzHRWBIDQUIi+D1fIgGLGG3qVVoQP9aIBQQDKkKyImM01tw6FgW3cM/k5B8qnA= 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=WWsi0mk4; arc=none smtp.client-ip=209.85.214.175 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="WWsi0mk4" Received: by mail-pl1-f175.google.com with SMTP id d9443c01a7336-2cf27856f9cso17056725ad.2 for ; Fri, 14 Aug 2026 22:19:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1786771199; x=1787375999; 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=jA30uY0QMPf30Z8XdJGvSBccQdQbzrAZ0FgVMAHJpg0=; b=WWsi0mk4ETZ49XKeE1MtclzG9sH5xiXZxA8OvQKyfYPMtN7vJmJxQi0Fx15aEmsR2a IGuYG1yD2D7DM4oKzID14btMpWWVB2M7VLiyfi6jzu4cJZn8jX71boAD2U9Jw1QD03HA 35ETg6+vQgjxTpi75F9rQLULpvMU0TKAJS5u/5IL3tbtJu7GuHgAAoy5cZvXPfwuS8hU h0H5xVJ7UWLE9XCiSFiKu4PStN60BwHIzxX2+/RPMuzsI0ip9FZkT1jh5K3y44/RupBc +F5zUBKwSMdYFKmpoGE2LPGdtlIf43uZqjXo7ypIyj/Uor1ti4PZIkYPOSkvL6yLfGNB Hr0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786771199; x=1787375999; 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=jA30uY0QMPf30Z8XdJGvSBccQdQbzrAZ0FgVMAHJpg0=; b=YxX6MQQqRSQYNiFccEaHi7ihb742jXG17nm8u+7o2UU2Dht6FVLx8BSqsIGkdFinlu PjRitZvC1rTRdnUWQo7E/UWZx89w6MdWJbowVv9udYBR4JrfLQoz7lgWe8qD+TUapEi3 tNnuTFneTv+ZUEr+V/gGqh+h6qahiLidKQZOf1s7p73xfKANmoj17xutY2nnjrQS41hr PfL8MqyForWF5U5jykkZ+VuJW/wGiWvTWjzSg0RXJnJKfRHVr9J0mIVVW8ZqKPn/MmYG H8dcZuj/Gr6c7pig/YsBibgMy3GN6gOJ8QfyaOcP1OOSjsZF9HOqs6lf+hvaDDM50wO3 +kvw== X-Forwarded-Encrypted: i=1; AHgh+Rr61D8LA2dRDt6m5MZjFzNqZzNwws9mSE4t/kXk48h7EGlKBaE41CqkjRq94TQHPWzZOdTyn2lT2n77kx8=@vger.kernel.org X-Gm-Message-State: AOJu0YxZ1eup1LjRxLoh3aAPvss4RxWSoVljmmTVLA2R60IloBQL4Ku1 tdM+DfP84AQEAAL3NS3PuioK1VVNg/3BqC+OeN8R1lSsu9MOcewZ11TBG89vNmBM X-Gm-Gg: AR+sD13L3rwGRfqyw2f8RjAgjepFOl1MwgsmAZnSmfwFOTc8QApZhFpCrK76ARTNxvO ruCNarXRSNUDb+FXMxbE/P+zOhpW5O+PCAeaElwPW4tkE0CObOlJWSuIX5m3ieh1R5aW37dvPOY 7PiQEUqQRlQcfcWy69WKIGslvLGi8GCKF+pCFetGEZ/Qn+JIOy5yKl2JkVJVmG8eONTYLBKe2aX Sz3qN92QbNfBoR46hNp3yVa7+5sTNbI2KK2qi+cbsNF8FO/SVBhJpt3q77SSrnsqEq0T6L+NhL8 f9ntm6nMNuV7AOdwXSFL3LWixBYuMwmtuX5LmVW1EwndD6uRT4Oug0yEyf5Vk9JlPsrBeAnx+1N O/1oT9u9nY7urm25ML0SA6AuHR1zIqXtYvcNTOp2jhw8eH2KCG58ZC0pIceVNe63kr70+ZXzo7a szz2E2sfm7qzZ2Dzw3SaMPKAn1fDOvo1exI2H7hG1S/goAHYc5V38Fu7NomNuk2oHHdKI26gxz X-Received: by 2002:a17:90b:586b:b0:381:bc4c:da5b with SMTP id 98e67ed59e1d1-3933b91c2ddmr11148842a91.18.1786771199166; Fri, 14 Aug 2026 22:19:59 -0700 (PDT) Received: from localhost.localdomain ([49.79.111.198]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-394ea96c7fcsm5269702a91.3.2026.08.14.22.19.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Aug 2026 22:19:58 -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, Vernon Yang Subject: [PATCH v2 0/3] mm: khugepaged: fix tracepoint UAF Date: Sat, 15 Aug 2026 13:19:21 +0800 Message-ID: <20260815051924.194810-1-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(). 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. 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 | 23 ++++++++++++++++------- 2 files changed, 25 insertions(+), 16 deletions(-) base-commit: 075b74841bd0065a3bda3440873c747938e69b68 -- 2.53.0