From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7AAA93BA239 for ; Mon, 27 Apr 2026 12:55:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777294526; cv=none; b=PJ/f4Q023g9SGoOvxgkdEnuB6w5Zr3hxm7QivXM5fEHwuICpGq5xxPVY0RmvFmHNO1DC3eEBJUgMp5M1Q1ZTfZJVhw/h2Zwr3uRpmRLEeGlSPXwXDZFHGgUFcv2pFzxe1qVsZYgJ3FJegb4tPw707lH8dgL86MmNAwcxj4Hf+2A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777294526; c=relaxed/simple; bh=/SLSKbEVu3l6hK1r5zozAmCAcb6Pe2cA6EyW0AMKsnc=; h=Date:To:From:Subject:Message-Id; b=sAg6e5sr61/lut3qKb2NrAVwANPpoyUwrCslVeTmCH0lPfaQeKzafvj0Ih1R5TdKnCwqvX1MCv8wAUKRIBONZy+k//+AzAj9EqZAgbKcRU+hYI0IQmcBJZ4bHAjHOU58/IefSmYrZMIfxherE29suqjycTiJAY5bBBAG+UOo1Y4= 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=Ux/n9EYz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Ux/n9EYz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1267FC19425; Mon, 27 Apr 2026 12:55:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777294526; bh=/SLSKbEVu3l6hK1r5zozAmCAcb6Pe2cA6EyW0AMKsnc=; h=Date:To:From:Subject:From; b=Ux/n9EYzCZihlmAALr1nvTRgQyRdejMttXBOKq8Yo9aISJkLLtWhhMFcD2FXeW3sc WzJNv39cqCJ+1zWDAgMU7RvpZyTS1t69NmB3gF0dpdYml60WhOMB8MqheQtoNbz5yH zQ8tZlxLSaYIQx1L/XraKzTkKLtsemkQGHC5KpKg= Date: Mon, 27 Apr 2026 05:55:25 -0700 To: mm-commits@vger.kernel.org,usama.arif@linux.dev,rppt@kernel.org,peterx@redhat.com,ljs@kernel.org,liam.howlett@oracle.com,jannh@google.com,devnexen@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-userfaultfd-detect-vma-type-change-after-copy-retry-in-mfill_copy_folio_retry.patch removed from -mm tree Message-Id: <20260427125526.1267FC19425@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/userfaultfd: detect VMA type change after copy retry in mfill_copy_folio_retry() has been removed from the -mm tree. Its filename was mm-userfaultfd-detect-vma-type-change-after-copy-retry-in-mfill_copy_folio_retry.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/userfaultfd: detect VMA type change after copy retry in mfill_copy_folio_retry() Date: Fri, 24 Apr 2026 19:36:38 +0100 mfill_copy_folio_retry() drops mmap_lock for the copy_from_user() call. During this window, the VMA can be replaced with a different type (e.g. hugetlb), making the caller's ops pointer stale. Subsequent use of the stale ops would dispatch into the wrong per-vma handlers. Capture the VMA's ops via vma_uffd_ops() before dropping the lock and compare against the current vma_uffd_ops() after re-acquiring it. Return -EAGAIN if they differ so the operation can be retried. This avoids comparing against the caller's ops which may have been overridden to anon_uffd_ops for MAP_PRIVATE file-backed mappings. Link: https://lore.kernel.org/20260424183638.196227-1-devnexen@gmail.com Fixes: 6ab703034f14 ("userfaultfd: mfill_atomic(): remove retry logic") Reported-by: Usama Arif Closes: https://lore.kernel.org/all/20260410114809.3592720-1-usama.arif@linux.dev/ Signed-off-by: David Carlier Acked-by: Mike Rapoport (Microsoft) Cc: Jann Horn Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Peter Xu Signed-off-by: Andrew Morton --- mm/userfaultfd.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/mm/userfaultfd.c~mm-userfaultfd-detect-vma-type-change-after-copy-retry-in-mfill_copy_folio_retry +++ a/mm/userfaultfd.c @@ -443,8 +443,10 @@ static int mfill_copy_folio_locked(struc return ret; } -static int mfill_copy_folio_retry(struct mfill_state *state, struct folio *folio) +static int mfill_copy_folio_retry(struct mfill_state *state, + struct folio *folio) { + const struct vm_uffd_ops *orig_ops = vma_uffd_ops(state->vma); unsigned long src_addr = state->src_addr; void *kaddr; int err; @@ -465,6 +467,14 @@ static int mfill_copy_folio_retry(struct if (err) return err; + /* + * The VMA type may have changed while the lock was dropped + * (e.g. replaced with a hugetlb mapping), making the caller's + * ops pointer stale. + */ + if (vma_uffd_ops(state->vma) != orig_ops) + return -EAGAIN; + err = mfill_establish_pmd(state); if (err) return err; _ Patches currently in -mm which might be from devnexen@gmail.com are mm-hugetlb-restore-reservation-on-error-in-hugetlb_mfill_atomic_pte-resubmission-path.patch mm-page_io-rename-swap_iocb-fields-for-clarity.patch