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 stable@vger.kernel.org.

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 1723f04caacb32cadc4e063725d836a0c4450694 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024071539-magnetize-nimble-15ba@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

1723f04caacb ("Fix userfaultfd_api to return EINVAL as expected") 2ff559f31a5d ("Revert "userfaultfd: don't fail on unrecognized features"") 914eedcb9ba0 ("userfaultfd: don't fail on unrecognized features") b1f9e876862d ("mm/uffd: enable write protection for shmem & hugetlbfs") 824ddc601adc ("userfaultfd: provide unmasked address on page-fault") 964ab0040ff9 ("userfaultfd/shmem: advertise shmem minor fault support") c949b097ef2e ("userfaultfd/shmem: support minor fault registration for shmem") 00b151f21f39 ("mm/userfaultfd: fail uffd-wp registration if not supported") b8da5cd4e5f1 ("userfaultfd: update documentation to describe minor fault handling") f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl") 7677f7fd8be7 ("userfaultfd: add minor fault registration mode") 44835d20b2a0 ("mm: add FGP_ENTRY") 8f251a3d5ce3 ("hugetlb: convert page_huge_active() HPageMigratable flag") d6995da31122 ("hugetlb: use page.private for hugetlb specific page flags") 99ca0edb41aa ("Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1723f04caacb32cadc4e063725d836a0c4450694 Mon Sep 17 00:00:00 2001 From: Audra Mitchell audra@redhat.com Date: Wed, 26 Jun 2024 09:05:11 -0400 Subject: [PATCH] Fix userfaultfd_api to return EINVAL as expected

Currently if we request a feature that is not set in the Kernel config we fail silently and return all the available features. However, the man page indicates we should return an EINVAL.

We need to fix this issue since we can end up with a Kernel warning should a program request the feature UFFD_FEATURE_WP_UNPOPULATED on a kernel with the config not set with this feature.

[ 200.812896] WARNING: CPU: 91 PID: 13634 at mm/memory.c:1660 zap_pte_range+0x43d/0x660 [ 200.820738] Modules linked in: [ 200.869387] CPU: 91 PID: 13634 Comm: userfaultfd Kdump: loaded Not tainted 6.9.0-rc5+ #8 [ 200.877477] Hardware name: Dell Inc. PowerEdge R6525/0N7YGH, BIOS 2.7.3 03/30/2022 [ 200.885052] RIP: 0010:zap_pte_range+0x43d/0x660

Link: https://lkml.kernel.org/r/20240626130513.120193-1-audra@redhat.com Fixes: e06f1e1dd499 ("userfaultfd: wp: enabled write protection in userfaultfd API") Signed-off-by: Audra Mitchell audra@redhat.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Andrea Arcangeli aarcange@redhat.com Cc: Christian Brauner brauner@kernel.org Cc: Jan Kara jack@suse.cz Cc: Mike Rapoport rppt@linux.vnet.ibm.com Cc: Peter Xu peterx@redhat.com Cc: Rafael Aquini raquini@redhat.com Cc: Shaohua Li shli@fb.com Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index eee7320ab0b0..17e409ceaa33 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -2057,7 +2057,7 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, goto out; features = uffdio_api.features; ret = -EINVAL; - if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES)) + if (uffdio_api.api != UFFD_API) goto err_out; ret = -EPERM; if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE)) @@ -2081,6 +2081,11 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx, uffdio_api.features &= ~UFFD_FEATURE_WP_UNPOPULATED; uffdio_api.features &= ~UFFD_FEATURE_WP_ASYNC; #endif + + ret = -EINVAL; + if (features & ~uffdio_api.features) + goto err_out; + uffdio_api.ioctls = UFFD_API_IOCTLS; ret = -EFAULT; if (copy_to_user(buf, &uffdio_api, sizeof(uffdio_api)))