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| author | David Hildenbrand <david@redhat.com> | 2025-05-16 15:39:44 +0300 |
|---|---|---|
| committer | Claudio Imbrenda <imbrenda@linux.ibm.com> | 2025-05-28 15:13:20 +0300 |
| commit | 3ec8a8330a1aa846dffbf1d64479213366c55b54 (patch) | |
| tree | 4876daec30aecd0220dd6298f01bf3fa701abd9f | |
| parent | 8ffd015db85fea3e15a77027fda6c02ced4d2444 (diff) | |
| download | linux-3ec8a8330a1aa846dffbf1d64479213366c55b54.tar.xz | |
s390/uv: Don't return 0 from make_hva_secure() if the operation was not successful
If s390_wiggle_split_folio() returns 0 because splitting a large folio
succeeded, we will return 0 from make_hva_secure() even though a retry
is required. Return -EAGAIN in that case.
Otherwise, we'll return 0 from gmap_make_secure(), and consequently from
unpack_one(). In kvm_s390_pv_unpack(), we assume that unpacking
succeeded and skip unpacking this page. Later on, we run into issues
and fail booting the VM.
So far, this issue was only observed with follow-up patches where we
split large pagecache XFS folios. Maybe it can also be triggered with
shmem?
We'll cleanup s390_wiggle_split_folio() a bit next, to also return 0
if no split was required.
Fixes: d8dfda5af0be ("KVM: s390: pv: fix race when making a page secure")
Cc: stable@vger.kernel.org
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20250516123946.1648026-2-david@redhat.com
Message-ID: <20250516123946.1648026-2-david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
| -rw-r--r-- | arch/s390/kernel/uv.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index 9a5d5be8acf4..2cc3b599c7fe 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -393,8 +393,11 @@ int make_hva_secure(struct mm_struct *mm, unsigned long hva, struct uv_cb_header folio_walk_end(&fw, vma); mmap_read_unlock(mm); - if (rc == -E2BIG || rc == -EBUSY) + if (rc == -E2BIG || rc == -EBUSY) { rc = s390_wiggle_split_folio(mm, folio, rc == -E2BIG); + if (!rc) + rc = -EAGAIN; + } folio_put(folio); return rc; |