From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 BBC2D31280F for ; Thu, 11 Dec 2025 12:59:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765457981; cv=none; b=cqn8PHj++UQZi3dBORt9rcYpmYuXfF92tKaHy6wjlR1um/YjDwIXhFiQ1cjIprz23gNApUH7S46bkhltR1i9ooW+lFlb1kU/E8Toe8vDReXAOt32vzEtO2VPOpGpG7/YTgRLlvq5ff/JoY3gm8JwejrCAg2HVL69rrL+tbp+gMg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765457981; c=relaxed/simple; bh=3sl+EeKgoic1meY3AExo8vX55CuahumVE/hloKxx6Fs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=SVo0mGhIdnKLSzSWoX9S3M6r5mYsgUQkTlE4DHcNOMRx70IPC6cKI0tZXQIiypb8h7+0QKiS5COegVi6DSXv9nCrhne4HzexWKdE3mELc8RxrqdS+M3zF+ujJd/XtK3edVGvUbAKQlA8GMdoC2HXNBPOPZST7WglQ4A91qP7qdo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--smostafa.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ZCPYkaAa; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--smostafa.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZCPYkaAa" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-477939321e6so430385e9.0 for ; Thu, 11 Dec 2025 04:59:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1765457978; x=1766062778; darn=lists.linux.dev; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=Z5uF5F4n44uHHmtIbXF2UG9WJO+vO8dPMrZl97vxG7I=; b=ZCPYkaAaUpldrytWOo6XV1Rv11HtdOXYCoU1bpRDx02OBXOPIzqzClXY73hY0mcn2P PacAC1NhecdyYv4QXCcUceHRobeEAXO4T8dNkrun6Qnv6L8exQj9tUNaeTDvLs5LcoQx KRELFsb9MBAbIE10hQLvGr/2rRGmhQbHx74EGjq1Ji+t+2vegUgupvwsZpbuZafeGcKm rjNN0nTr5IaSZmkQN6Oz3CHHBmg3DoyjUO/22ui5TIabXguQPJCtTBks067VTr9frclK hDE3CdRk8l/7Beq1v8zpAkH4+61hjy141lyGGPkWVszsdiKaNPyMNUvwOMK1rwpTdxZU ZQWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765457978; x=1766062778; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=Z5uF5F4n44uHHmtIbXF2UG9WJO+vO8dPMrZl97vxG7I=; b=lknjApZsfvVtwuU7BfaszxM/g4kPGdABeXg7H6SeN/09xHWnuwsLYz7ZJ72nVRA7xW xcFqBV4JgAGK5+CbkBtnYeGFpkG/4fgyQIsmQ/JpJJs7uFzdYQfouu8XlV2f5FccDePa dZoYBQnNsH2HmxSIEUGA+tDRq3gdnq+Tl/cKY98vcZRzp4bKFeP10RJEO4ojxxGGpzzo f9W6PZdOBfkIfFvcXru0yppfNdj1wuqvyMWbwEPGtoRk1/PnBehOVf9Zguh8gVpUU65k gkBjdrTtOdlY1Bb90+no7ntS6mAokSd4ekdutjBTbYRuAHDPLjTQMYN2g6+rxjFBDVot aHrw== X-Forwarded-Encrypted: i=1; AJvYcCVw8ah7ZSkhWwEzF8Fx7VygEdKfRF5QxOXln+JY/mia5bntb8ywyQ5gs/2yuVekWLX5PY2Jyg==@lists.linux.dev X-Gm-Message-State: AOJu0Yy5QEcsKntNMoZKcw7l97Bn+/q8rDNOnBDnutzMuGQ0zO2hQT50 ANilUgK08a/+66B4PCctQ6I8IHcZItdIX26PM1IBlpHlu56kXtpxQt3cdhY6RxODc+M1FzT76a/ ObQ5xUzUWco8xkw== X-Google-Smtp-Source: AGHT+IEzrlA/D2+Mzh+inyFuHFFtWJkme4dxyA7uMTZWAlUftjFK9QGFcKLMuEzVGMzE2aQGlGAf5icqRkZxhw== X-Received: from wrvk5.prod.google.com ([2002:a5d:5185:0:b0:425:f04a:4d91]) (user=smostafa job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:2087:b0:42b:4177:7136 with SMTP id ffacd0b85a97d-42fa3afd48dmr6497099f8f.32.1765457978004; Thu, 11 Dec 2025 04:59:38 -0800 (PST) Date: Thu, 11 Dec 2025 12:59:28 +0000 In-Reply-To: <20251211125928.3258905-1-smostafa@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251211125928.3258905-1-smostafa@google.com> X-Mailer: git-send-email 2.52.0.223.gf5cc29aaa4-goog Message-ID: <20251211125928.3258905-5-smostafa@google.com> Subject: [PATCH v4 4/4] iommu: debug-pagealloc: Check mapped/unmapped kernel memory From: Mostafa Saleh To: linux-mm@kvack.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: corbet@lwn.net, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, xiaqinxin@huawei.com, baolu.lu@linux.intel.com, rdunlap@infradead.org, Mostafa Saleh Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Now, as the page_ext holds count of IOMMU mappings, we can use it to assert that any page allocated/freed is indeed not in the IOMMU. The sanitizer doesn=E2=80=99t protect against mapping/unmapping during this period. However, that=E2=80=99s less harmful as the page is not used by the kernel. Signed-off-by: Mostafa Saleh --- drivers/iommu/iommu-debug-pagealloc.c | 23 +++++++++++++++++++++++ include/linux/iommu-debug-pagealloc.h | 14 ++++++++++++++ include/linux/mm.h | 5 +++++ 3 files changed, 42 insertions(+) diff --git a/drivers/iommu/iommu-debug-pagealloc.c b/drivers/iommu/iommu-de= bug-pagealloc.c index 4639cf9518e6..424e00cd103b 100644 --- a/drivers/iommu/iommu-debug-pagealloc.c +++ b/drivers/iommu/iommu-debug-pagealloc.c @@ -9,6 +9,7 @@ #include #include #include +#include =20 #include "iommu-priv.h" =20 @@ -73,6 +74,28 @@ static size_t iommu_debug_page_size(struct iommu_domain = *domain) return 1UL << __ffs(domain->pgsize_bitmap); } =20 +static bool iommu_debug_page_count(const struct page *page) +{ + unsigned int ref; + struct page_ext *page_ext =3D page_ext_get(page); + struct iommu_debug_metadata *d =3D get_iommu_data(page_ext); + + ref =3D atomic_read(&d->ref); + page_ext_put(page_ext); + return ref !=3D 0; +} + +void __iommu_debug_check_unmapped(const struct page *page, int numpages) +{ + while (numpages--) { + if (WARN_ON(iommu_debug_page_count(page))) { + pr_warn("iommu: Detected page leak!\n"); + dump_page_owner(page); + } + page++; + } +} + void __iommu_debug_map(struct iommu_domain *domain, phys_addr_t phys, size= _t size) { size_t off, end; diff --git a/include/linux/iommu-debug-pagealloc.h b/include/linux/iommu-de= bug-pagealloc.h index a439d6815ca1..46c3c1f70150 100644 --- a/include/linux/iommu-debug-pagealloc.h +++ b/include/linux/iommu-debug-pagealloc.h @@ -13,6 +13,20 @@ DECLARE_STATIC_KEY_FALSE(iommu_debug_initialized); =20 extern struct page_ext_operations page_iommu_debug_ops; =20 +void __iommu_debug_check_unmapped(const struct page *page, int numpages); + +static inline void iommu_debug_check_unmapped(const struct page *page, int= numpages) +{ + if (static_branch_unlikely(&iommu_debug_initialized)) + __iommu_debug_check_unmapped(page, numpages); +} + +#else +static inline void iommu_debug_check_unmapped(const struct page *page, + int numpages) +{ +} + #endif /* CONFIG_IOMMU_DEBUG_PAGEALLOC */ =20 #endif /* __LINUX_IOMMU_DEBUG_PAGEALLOC_H */ diff --git a/include/linux/mm.h b/include/linux/mm.h index 7a1819c20643..3763b71a7d3e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -36,6 +36,7 @@ #include #include #include +#include =20 struct mempolicy; struct anon_vma; @@ -4133,12 +4134,16 @@ extern void __kernel_map_pages(struct page *page, i= nt numpages, int enable); #ifdef CONFIG_DEBUG_PAGEALLOC static inline void debug_pagealloc_map_pages(struct page *page, int numpag= es) { + iommu_debug_check_unmapped(page, numpages); + if (debug_pagealloc_enabled_static()) __kernel_map_pages(page, numpages, 1); } =20 static inline void debug_pagealloc_unmap_pages(struct page *page, int nump= ages) { + iommu_debug_check_unmapped(page, numpages); + if (debug_pagealloc_enabled_static()) __kernel_map_pages(page, numpages, 0); } --=20 2.52.0.223.gf5cc29aaa4-goog