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=1794090302; b=naB47dv/lrc3uBNckeWk3VFzBghlQeEn5dCgWyL/B9h1Cxy7B3p1WKRHPXb+pwwA8vsf xjKIDWbdRVsnXUNAYMp/wuvTAyr9KWMHmGM/A+Y+6TvCl0UA202CUOZ5q6+pocf/MRsjf 9oDZTvcdAyR52pRUgHyCNX+AceOtQiR7Xgv8Z1BId31QZ2dtXzF86wevlhD8PTrHtC2/v asFsivor+T2lNizgiSJZrRDSIwjPXQl+XE2Sf4OFa7y2kHzEYypAbMKZ80R7vS+oZol6P 07QWbnmhQIN2WIXC29tDS4bcAlY8pYSEFcYsiJ+0dVIe4sx4McyiWL1MPVMl9w2+9Ew== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794090302; 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=DG8oRhfIWbgsbq+OdHU4Yz0/pdX6RmBzMqGp7V8doOh/yXyucHLDuFDQwkLMr3Fwi7v/ LIlCt2ZF/1M0zQ+1ju2DVVg6onZJ+rZj8TyPCB2Jte64N1dr/iIZF3yTxXcISDMYQupW8 nME/XG7LA/9Bliyto3uSF/AfQE/mImPu5x7KIrHReIfdYvT6FMYM1oikRbiwDGlzwWFDJ z+leVNKYLHZ7+VLYQJWVDI9kSNR36wZHuWu9dqNMjBO2Jpd4LIXbcZQCpwZxXIPX3bclj XXmXft6MR1uppY1UAnttRoQFY40H1h0UW55teEEu6pPePuyTmh4r6UFysViQ4Ztbd9A== 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=Ju6Cfz96; 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 3DB12606A32C; Sat, 7 Nov 2026 22:25:02 +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=Ju6Cfz96 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2EB901F008A1; Sat, 7 Nov 2026 22:24:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794090302; bh=pHhzsFK46xamHLjxn99YRGd8ys0XhYnUbLCGMyb//rs=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Ju6Cfz960666XG0yk6b/gqWUfTYFPewkV84zF0+CiI6bHhEhgdSqF+x9V55sa4yrD P8vI64/cOlDJ8RkSsq6dPjKek/Ywv7qDM0to8D8N2TlPLfYAiaeqRU3ygvS8fFNzW0 qcTQOlqQLVfLWhOxezpaaFBCmaLbjjCpvynfNXTz0gnEJUSOEgjRmkMt9fkFM6F3tl VVSx46jVnCDPGXao4tWJh/skNSlPw2a4bikZ2UpqJJNMOTXeCQm1pQqdwuGsnJ9i3g 26F2C/HSmE4JxmGcGSJXwM4K6RcTQ+dJwP+iIOXHVEOiN2wgDA/sINnzqBI+g4eSXl jVciwuVDKOX5A== From: "David Hildenbrand (Arm)" Date: Sat, 07 Nov 2026 23:23:40 +0100 Subject: [PATCH v2 4/5] 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: <20261107-refcount_overflow_stable-v2-4-c38f6809b106@kernel.org> References: <20261107-refcount_overflow_stable-v2-0-c38f6809b106@kernel.org> In-Reply-To: <20261107-refcount_overflow_stable-v2-0-c38f6809b106@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 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, 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=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLLeL2W0bHadVfTlfHZP64PqGzeK3Teah+fH6VZ+cpw0a 8b3bK2FHaUsDGIcDLJiiixBwfcNXr5cV1vtxscMM4eVCWQIAxenAEykZDkjw1KTmIgAwY894ov6 fFjzPUWdLKuu84grbV43U35iHm+dN8Mf7jCua4Zxe5lMu1PvLr2yifeOxIUA3UXyWnqt+rHOG/O 5AA== 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