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=1794274083; b=leQCTCdx+bZ51lPomZARjQPGMsgJ4/icpNefGpt4sbL0X1t5z4mfNkoWWkbrHVHEUvSz z23H+SGVc4WNEgTTDfJsOvegurjyAcn/Qwd1GikrQaACWshfPXUD/1WigWn0ol2Qt9UVf 92ZNXtgbWFTPF0i4e22hb+27wDOjVC1bomWZAzdsLWuPWtkdMISa0xt0u3h+Yea3ikPC2 Z2J84SG0mcLZW4ebUwKwf2dUDu5eJoeMkB1QEiN1Dfp9j3KLqEwBoLOb3NjmoIkBTeOnR lW4lAyg9tUkXJaKSD/Xat3RhSNUOVtP4eulIZe+FTIBNdx8g+h6h7DArYZ10QZCrbuw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794274083; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=/WFCy3Z9K5F9o4z/9pIqc8KG9sMGZjs+a5cy9XK+Z4Q=; b=PlBtJylpB0/bXYi2OPTMzxlW0LJJnBZJ+kCAuVNsiEdQ11D7q06Z6R4i0jdrRvs7gaNn EbdYlipK2ZsVixuHtLv0wuA0r7KfC5OuDAeE0Sf1OQ94YmNFm7A5xFkBmzE7mR3IncD8k PduYLDwstsrp+5FlBXj5AbcBpTCTTAbgC+qqYtt3WC5k7tN3c9c91oLqjIWyhUSHD8h9A Nm27t+FsVpdbZNCZMS9TurSe9yWzg0W9XH/pCEx+0lv57Jcvg8X5xuDf2AesLW6mTTkFZ keFw0D4bNk6+QPIsQ+CKL62yxwM+vd4QR4itxu5YepNpRUZvaisWGhbpaTgEdzei5Sw== 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=Wevv4fmu; 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 5D836606A32E for ; Tue, 10 Nov 2026 01:28:03 +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=Wevv4fmu Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D5281F0089F; Tue, 10 Nov 2026 01:28:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794274083; bh=/WFCy3Z9K5F9o4z/9pIqc8KG9sMGZjs+a5cy9XK+Z4Q=; h=From:To:Cc:Subject:Date; b=Wevv4fmuLriJOuDp8SDs4obeEwIRelLRnZTyxly1NZKMMEKJqgvf7WSJQPLgkA/nb XYXg7IBDhMk80/NJNfax5GtfTxr/kN0oSJZNVXeF27KLt4tB8O7AttXseLIh7h2tHq cerLY7gnrciFz6TUl3NY0vsPZb4PgasOsjY+bdRz+He5hlTQjlV0ExpkvZK662Ms1B rH/92spAOTgT9/WiGFjCLpesGTA3jCyCoMnAksWMTdqfO3TUNdDy+oq9Pl8y4ZSBkT xHuSS7CuQY4If8Z5d+eV0g3R73mhpK3YO35a1rKGvojaYoXGOveuzIpVUrJe+/0olX 5KDLmYVLEb8pg== From: Sasha Levin To: josef@toxicpanda.com, rppt@kernel.org, ljs@kernel.org, usama.anjum@arm.com, david@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] mm/userfaultfd: wake all waiters on unregister" failed to apply to 5.10-stable tree Date: Mon, 9 Nov 2026 20:28:01 -0500 Message-ID: <20261109202801-failed-5.10-3afb19d68cc5@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@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: 8bit The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 3afb19d68cc5e7851fdb1069c8094af97bd80417 # git commit -s git send-email --to '' --in-reply-to '20261109202801-failed-5.10-3afb19d68cc5@kernel.org' --subject-prefix 'PATCH 5.10.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 3afb19d68cc5e7851fdb1069c8094af97bd80417 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Sat, 31 Oct 2026 10:39:53 +0100 Subject: [PATCH] mm/userfaultfd: wake all waiters on unregister UFFDIO_UNREGISTER only wakes pending faults if VM_UFFD_MISSING is set. Threads waiting on write-protect, minor or RWP faults can therefore remain asleep after unregistering a range that does not track missing faults. Wake pending faults regardless of the registration mode so they can retry without an explicit UFFDIO_WAKE or closing the userfaultfd. This matches the existing behavior for missing faults, including removing unread fault messages for the woken waiters. Fix generated by an LLM and sent by Josef Bacik in private. Fixes: 63b2d4174c4a ("userfaultfd: wp: add the writeprotect API to userfaultfd ioctl") Cc: stable@vger.kernel.org Signed-off-by: Josef Bacik [ david: rebase; simplify description ] Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Lorenzo Stoakes (ARM) Tested-by: Muhammad Usama Anjum Link: https://patch.msgid.link/20261031-fixes_core-v3-24-d6437171ecc3@kernel.org Signed-off-by: David Hildenbrand (Arm) --- mm/userfaultfd.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 3ca04b582329f..be630674fda9b 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -3977,6 +3977,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, ret = 0; for_each_vma_range(vmi, vma, end) { + struct userfaultfd_wake_range range; + cond_resched(); /* VMA not registered with userfaultfd. */ @@ -3994,18 +3996,14 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, /* Prevent new userfaults from being queued after the wakeup. */ vma_start_write(vma); - if (userfaultfd_missing(vma)) { - /* - * Wake any concurrent pending userfault while - * we unregister, so they will not hang - * permanently and it avoids userland to call - * UFFDIO_WAKE explicitly. - */ - struct userfaultfd_wake_range range; - range.start = start; - range.len = vma_end - start; - wake_userfault(vma->vm_userfaultfd_ctx.ctx, &range); - } + /* + * Wake any concurrent pending userfault while we unregister, + * so they will not hang permanently and it avoids userland to + * call UFFDIO_WAKE explicitly. + */ + range.start = start; + range.len = vma_end - start; + wake_userfault(ctx, &range); vma = userfaultfd_clear_vma(&vmi, prev, vma, start, vma_end); -- 2.53.0