From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5D0B644CF52; Tue, 16 Jun 2026 15:40:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781624444; cv=none; b=K6Z9xEBX9Hl8hoq3dnvZOFUF0t+BS3Tm55ysI5uaUCFKFde+psIk2ChSS5j8MlRXUSwhyQv8ip3pRElKunUcQJ9nFNDBBgG+7DgqeEzmk565YfqyPEnfY3pgUqL3XBT1b+7ZfjbsAlfB0kvnj/G2ua3NPLfyXXEMUIDV7M8cfro= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781624444; c=relaxed/simple; bh=De92+8TcrcaEkvxv2GyesLIvnx3BP1sM5QZw910CiTc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LhcpYDrvpVNPD2ymY3QmliPusKbfmeVzW48rQTgeky+JcIBZgYwDJHmmFobD2DZpecKsBlOg4r++V+B0bUEUD47q3T6D4g4DClc0Nzh3oEe3VSSisxntVRSzJc8FlMuVWWNUMAEu2rW2j26kNWhxGJLuEXAsmjxtOkGX42tfxi4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pDC14v5b; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pDC14v5b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 185B41F000E9; Tue, 16 Jun 2026 15:40:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781624443; bh=rqa8hurC/LdTTkg7yeoHqh7QdAVjm+YLm2yfF8ZMR74=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=pDC14v5bRxJmfzrCL0yYsxiffFSUCkWdboZg/JBwIHU+b4f9pc8VROhwVqUQ9tDt8 Xe7J91YOcrSe8xXiGf/3bGVTi0tI985NlqUGyVCD50FijwZNt9BIpUhLgDw106uVsD KHtxL814WVOs8wQA62eja1CFCYfu3llZckKpFdp0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Carlier , Muchun Song , David Hildenbrand , Mina Almasry , Oscar Salvador , yuehaibing , Andrew Morton Subject: [PATCH 7.0 304/378] mm/hugetlb: restore reservation on error in hugetlb folio copy paths Date: Tue, 16 Jun 2026 20:28:55 +0530 Message-ID: <20260616145126.156282487@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145109.744539446@linuxfoundation.org> References: <20260616145109.744539446@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Carlier commit 40c81856e622a9dc59294a90d169ac07ea25b0b0 upstream. Two sites in mm/hugetlb.c allocate a hugetlb folio via alloc_hugetlb_folio() (consuming a VMA reservation) and then call copy_user_large_folio(), which became int-returning in commit 1cb9dc4b475c ("mm: hwpoison: support recovery from HugePage copy-on-write faults") and can now fail (e.g. -EHWPOISON on a hwpoisoned source page). On the failure path, folio_put() restores the global hugetlb pool count through free_huge_folio(), but the per-VMA reservation map entry is left marked consumed: - hugetlb_mfill_atomic_pte() resubmission path (UFFDIO_COPY) - copy_hugetlb_page_range() fork-time CoW path when hugetlb_try_dup_anon_rmap() fails (rare: pinned hugetlb anon folio under fork) User-visible effect: on UFFDIO_COPY into a private hugetlb VMA where the resubmission copy fails, the reservation for that address is leaked from the VMA's reserve map. A subsequent fault at the same address takes the no-reservation path, and under hugetlb pool pressure the task is SIGBUSed at an address it had previously reserved. The fork-time CoW path leaks the same way in the child VMA's reserve map, though it requires the much rarer combination of pinned hugetlb anon page + hwpoisoned source. Add the missing restore_reserve_on_error() call before folio_put() on both error paths. Link: https://lore.kernel.org/20260520044912.6751-1-devnexen@gmail.com Fixes: 1cb9dc4b475c ("mm: hwpoison: support recovery from HugePage copy-on-write faults") Signed-off-by: David Carlier Reviewed-by: Muchun Song Cc: David Hildenbrand Cc: Mina Almasry Cc: Muchun Song Cc: Oscar Salvador Cc: yuehaibing Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/hugetlb.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4996,6 +4996,7 @@ again: addr, dst_vma); folio_put(pte_folio); if (ret) { + restore_reserve_on_error(h, dst_vma, addr, new_folio); folio_put(new_folio); break; } @@ -6292,6 +6293,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_ folio_put(*foliop); *foliop = NULL; if (ret) { + restore_reserve_on_error(h, dst_vma, dst_addr, folio); folio_put(folio); goto out; }