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 06308367B98; Fri, 29 May 2026 03:51:08 +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=1780026670; cv=none; b=m4hMBLU5T17p4HPvns51LUdyfNkavzeeOt7oq9KHByhnGHkI17vDOyoqmy5kUGt5HM4tDAZAPUOjTk5xFnq0RiqVbWbGgZW15g/x6ftcnfeOnUyrDzjNUuoUcDzDuCFLnP4Y3mp2QpagrkzOyU2lXdqFsueWD5LPRnEtEEgqSI8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780026670; c=relaxed/simple; bh=6obA5AvI870lObVtys1NH172KzL4InSVVN8XceU5G4A=; h=Date:To:From:Subject:Message-Id; b=qnl+6BUfCxXY16T6Ly5xbX2Zht/nKKsIbGVoe/l9M93GWy5Cup2futhRp60QnLNKC5BTD7rudjcFNsQPfD9krHMVVK900EozCXsDMGhbao6zfvRyCOGxj6q9aTjn/QcqD9u/MAnVvQKT0mDTlK++AG2FEvyd+xA8H9wIVrE7y1U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=WhV626V9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="WhV626V9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 956CB1F000E9; Fri, 29 May 2026 03:51:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1780026668; bh=Mh9ywv87efi6Kt7xmCQtESrFiq2NQthv4Q0GN8+nPFU=; h=Date:To:From:Subject; b=WhV626V9VyaXt4Q76LVjqFPX/3Dj8jc84XKPCe33znU5dGaTKVQs9R38uBvG8ZfLn lKdPwynixWSFbEZd30b3RK7WvySd8ukJA84T2g3VAJAUV7wMeXBsSzbU8OOD7ETg31 RQBY37mEOapJ7I2ZXSC/918XsTPG1YpFNwgPllK4= Date: Thu, 28 May 2026 20:51:08 -0700 To: mm-commits@vger.kernel.org,yuehaibing@huawei.com,stable@vger.kernel.org,osalvador@suse.de,muchun.song@linux.dev,david@kernel.org,almasrymina@google.com,devnexen@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-hugetlb-restore-reservation-on-error-in-hugetlb-folio-copy-paths.patch removed from -mm tree Message-Id: <20260529035108.956CB1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/hugetlb: restore reservation on error in hugetlb folio copy paths has been removed from the -mm tree. Its filename was mm-hugetlb-restore-reservation-on-error-in-hugetlb-folio-copy-paths.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: David Carlier Subject: mm/hugetlb: restore reservation on error in hugetlb folio copy paths Date: Wed, 20 May 2026 05:49:12 +0100 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 --- mm/hugetlb.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/hugetlb.c~mm-hugetlb-restore-reservation-on-error-in-hugetlb-folio-copy-paths +++ a/mm/hugetlb.c @@ -4977,6 +4977,7 @@ 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; } @@ -6273,6 +6274,7 @@ 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; } _ Patches currently in -mm which might be from devnexen@gmail.com are mm-page_io-rename-swap_iocb-fields-for-clarity.patch mm-shrinker-avoid-out-of-bounds-read-in-set_shrinker_bit.patch mm-swap-pm-hibernate-atomically-replace-hibernation-pin.patch