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 EBBAB44E045; Tue, 16 Jun 2026 16:10:24 +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=1781626226; cv=none; b=Bj6dctw9jqx8Dpirn0m/IQy/o0mM+JUkOdd16v8PzkSa/nTLYTQ+8lRwModqJXJjKRt3LFEDwsEVK4oBR4YE7LFViOmeezsq2RM8BsClOOc5eG/NmrPXpyMG93hC9jNrNq6C5dxCc//lVRMAxhHJnL2Mbq0u1VEJo0Y3oM44n/4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781626226; c=relaxed/simple; bh=+22ka7+TPN49jP4XD7yCcTIFJzL7YXStf9RcM1A6YF8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I2yVr6s4w8KmrUwLAOZ+HdWnFKVCkX3VR3UJaklkWyP5FXaxstrYpmN5xIdUbQI8EM/vUm/0nd8bE8kmOjmdzuimAn3zOqJ28KGiaAhqKPs5ZrfymuLo3PAxiePIJy2vvvCqt3ZDkQe6xDRvWvng821v5HxTwF0gEH930ija+oQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=y6YfGf2t; 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="y6YfGf2t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1C5A1F000E9; Tue, 16 Jun 2026 16:10:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781626224; bh=Ml1fut3ArSi1XG6ncicnBMfVTlwBYq5N9LRQ+17643M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=y6YfGf2tm/UT3BX/u80zdChAujRx3UcZsIsSTK8V4JOscBKZNwzCZvt4VEuSDr5bq VfiIBdbQlNSNfsq4BHdrfqNchSIalowPtblMul2aoKTh5b7g0WQy6hnomwsgc/NIEW 9c29jGEqtuIjV7cHx508EXtiJbRx4JgU5Qw+F2gk= 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 6.18 254/325] mm/hugetlb: restore reservation on error in hugetlb folio copy paths Date: Tue, 16 Jun 2026 20:30:50 +0530 Message-ID: <20260616145111.210711054@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145057.827196531@linuxfoundation.org> References: <20260616145057.827196531@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 6.18-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 @@ -5696,6 +5696,7 @@ 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; } @@ -6987,6 +6988,7 @@ 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; }