From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794343080; b=a7G92n9iH5oFLcspuuoYntrDQ7PSnMEvor8PvGq2mnzoDO5rcELDYl4OR0F2e83wVLEP wwqN2jPF70P67AZvNq5f/1ph1BpSDPw/QG7l/tDLNWW7abEaYdz+/3dYu2X44wLhELvuR 4QuJAIXyADNjq7VJYr/VX5DtA76FNzHevPeg8May3Rxk0ALRvjnFJBHdv+wn76q+dDZdJ /v6VTdJjMS5Yt46VyWffsQhEodkkWschy4Zbo0qDikWCBA9tEOisqTdiLpMdBAyVaJSNf sRZhsRB2zpWlABXAVHk29va498KviH5M/6odebHEij5Z4WgVZu2clbSvendLz+qqO3w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794343080; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=pHhzsFK46xamHLjxn99YRGd8ys0XhYnUbLCGMyb//rs=; b=gcpmKqJdYEcg8sSYrhu1dJrltnTUM+wuNICWhKIOGJJREGnl0TbhMLPy5UA98XdEvWAd IFT8G7H+WvEQTE6V/J+kqqcJaPCrbPxgsP0fbPIhjxDSVVlJmHc24bUHZpSwcvGH3lDCF SzsmLn2ts5KtKKAYlT0m0rdkJthjRFCgtpMEbfdS1TMMkiKjSTy4mFC+8VCylY4TyoY3g DzQHEh1e0KjGAoyPI+MkHEb+qT++9u5xfoyQkMJsVMWSKbkhrVbGvzvxP9RjVayej9oZY n/XWgbHoW7xKQrhWBTyRz8ghF4hbuwpnrqEUpuH3ayPcrilG/LQAd5KluYK/wdXGlPw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=gWEhRREK; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CE45B60A2627; Tue, 10 Nov 2026 20:37:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=gWEhRREK Received: by smtp.kernel.org (Postfix) with ESMTPSA id B38231F008BD; Tue, 10 Nov 2026 20:37:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794343079; bh=pHhzsFK46xamHLjxn99YRGd8ys0XhYnUbLCGMyb//rs=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=gWEhRREK9FVVHGNpd2nGoRZ8s8g//Xfo+FROKWQm72DFOPJ0clcsk98bP/mbSEE15 8tWNbXJ6ZNTJnEuv0ZAUuKp6PFeH/15MVpNDyhm3dMZpIOcWjMjBN9nu1TGLpO8Fdm K938D0LjGqLb8R7ju5fJRrASjlZd+VkaeJ4987fZcckyNFHaLstEB4wbWA+Kp+AaEJ GbUCt5fezRqDI2Ol+HJEiFl3DN+nSnWYbbAasN0F9NQtdU2FPjnwK7OdH93/i4jZtb G7QVslVoA/cKhDVDIKtarFgGX4bz//b/KI9Ga/Jc7nXTTY8Tzkre99epxDmtOqTeVE Ix7wdKANaY+3g== From: "David Hildenbrand (Arm)" Date: Tue, 10 Nov 2026 21:35:44 +0100 Subject: [PATCH v3 4/9] iommufd: fix cleanup when adding memfd folio pins fails X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261110-refcount_overflow_stable-v3-4-318625d63a98@kernel.org> References: <20261110-refcount_overflow_stable-v3-0-318625d63a98@kernel.org> In-Reply-To: <20261110-refcount_overflow_stable-v3-0-318625d63a98@kernel.org> To: Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , "Matthew Wilcox (Oracle)" , Jan Kara , Andrew Morton , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Matthew Brost , Joshua Hahn , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Peter Xu , Johannes Weiner , Song Liu , Rik van Riel , Miklos Szeredi , Alexander Viro , Christian Brauner , Hugh Dickins , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , Arnd Bergmann , Jason Gunthorpe , Kevin Tian , "Joerg Roedel (AMD)" , Robin Murphy , Steve Sistare , John Hubbard , "Jose A. Perez de Azpillaga" , Josef Bacik , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Neal Cardwell , Kuniyuki Iwashima , Linus Torvalds Cc: "David Hildenbrand (Arm)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, fuse-devel@lists.linux.dev, linux-arch@vger.kernel.org, iommu@lists.linux.dev, netdev@vger.kernel.org, stable@vger.kernel.org, Jason Gunthorpe X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3608; i=david@kernel.org; h=from:subject:message-id; bh=fau3pBzKpQXLjgKtqqi0yzExsXgD+rlECuO7Pn/e1yI=; b=owGbwMvMwCF2QOXvyb15Z08znlZLYsj63BA+Y9ux4zLMk2e4PpP5oXDoUBfvZgmLYJ+T4Suvf 7qZaHHRsaOUhUGMg0FWTJHl2rqc1OA1rY5lUYZuMHNYmUCGMHBxCsBEki8w/E9vmOcWxrp9lUtt kNILo72njKafUJm6ob9t4eGK2tjDS1QZGXqWF/mFrH+wmGlO4dX2pglu6r/jEpRkppTqH5vx6V5 pKg8A X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A folio_add_pins() can fail after memfd_pin_folios() succeeded pinning a folio. Upcoming folio refcount limit checks will make this easier to trigger. Let's fix three problems in the error handling: 1. pfn_reader_release_pins() uses the allocated array size instead of the number of folios returned by memfd_pin_folios(). With large folios, cleanup can unpin uninitialized entries. Remember the number of returned folios and use that during cleanup. 2. pin_memfd_pages() returns on failure without releasing the pins acquired by the current call. Release the per-page pins for folios already expanded into the page array, and the single pins for the remaining folios. 3. pfn_reader_next() returns on failure before updating batch_end_index, even if the batch already contains successfully expanded folios. Update it before propagating the error so cleanup releases those pins as well. Fixes: 92687c793644 ("iommufd: pfn_reader for file mappings") Cc: stable@vger.kernel.org Reviewed-by: Lance Yang Reviewed-by: Jason Gunthorpe Signed-off-by: David Hildenbrand (Arm) --- drivers/iommu/iommufd/pages.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c index 2f6153108add7..fcdbde007a9ab 100644 --- a/drivers/iommu/iommufd/pages.c +++ b/drivers/iommu/iommufd/pages.c @@ -781,6 +781,7 @@ struct pfn_reader_user { struct file *file; struct folio **ufolios; size_t ufolios_len; + unsigned long ufolios_count; unsigned long ufolios_offset; struct folio **ufolios_next; }; @@ -800,6 +801,7 @@ static void pfn_reader_user_init(struct pfn_reader_user *user, user->file = (pages->type == IOPT_ADDRESS_FILE) ? pages->file : NULL; user->ufolios = NULL; user->ufolios_len = 0; + user->ufolios_count = 0; user->ufolios_next = NULL; user->ufolios_offset = 0; } @@ -843,6 +845,7 @@ static long pin_memfd_pages(struct pfn_reader_user *user, unsigned long start, offset >>= PAGE_SHIFT; user->ufolios_next = user->ufolios; + user->ufolios_count = nfolios; user->ufolios_offset = offset; for (i = 0; i < nfolios; i++) { @@ -859,8 +862,12 @@ static long pin_memfd_pages(struct pfn_reader_user *user, unsigned long start, } else { int rc = folio_add_pins(folio, npin - 1); - if (rc) + if (rc) { + unpin_user_pages(user->upages, + upages - user->upages); + unpin_folios(user->ufolios + i, nfolios - i); return rc; + } while (npin--) *upages++ = folio_page(folio, offset++); @@ -1251,14 +1258,14 @@ static int pfn_reader_next(struct pfn_reader *pfns) return -EINVAL; rc = pfn_reader_fill_span(pfns); + pfns->batch_end_index = pfns->batch_start_index + + pfns->batch.total_pfns; if (rc) return rc; if (WARN_ON(!pfns->batch.total_pfns)) return -EINVAL; - pfns->batch_end_index = - pfns->batch_start_index + pfns->batch.total_pfns; if (pfns->batch_end_index == pfns->span.last_used + 1) interval_tree_double_span_iter_next(&pfns->span); @@ -1320,7 +1327,7 @@ static void pfn_reader_release_pins(struct pfn_reader *pfns) if (!user->file) { unpin_user_pages(user->upages + start_index, npages); } else { - long n = user->ufolios_len / sizeof(*user->ufolios); + const unsigned long n = user->ufolios_count; unpin_folios(user->ufolios_next, user->ufolios + n - user->ufolios_next); -- 2.56.0