From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-s390@vger.kernel.org, kvm@vger.kernel.org,
linux-mm@kvack.org, David Hildenbrand <david@redhat.com>
Subject: [PATCH RFC 2/9] s390/gmap: don't unconditionally call pte_unmap_unlock() in __gmap_zap()
Date: Thu, 9 Sep 2021 16:59:38 +0200 [thread overview]
Message-ID: <20210909145945.12192-3-david@redhat.com> (raw)
In-Reply-To: <20210909145945.12192-1-david@redhat.com>
... otherwise we will try unlocking a spinlock that was never locked via a
garbage pointer.
At the time we reach this code path, we usually successfully looked up
a PGSTE already; however, evil user space could have manipulated the VMA
layout in the meantime and triggered removal of the page table.
Fixes: 1e133ab296f3 ("s390/mm: split arch/s390/mm/pgtable.c")
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/s390/mm/gmap.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index b6b56cd4ca64..9023bf3ced89 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -690,9 +690,10 @@ void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
/* Get pointer to the page table entry */
ptep = get_locked_pte(gmap->mm, vmaddr, &ptl);
- if (likely(ptep))
+ if (likely(ptep)) {
ptep_zap_unused(gmap->mm, vmaddr, ptep, 0);
- pte_unmap_unlock(ptep, ptl);
+ pte_unmap_unlock(ptep, ptl);
+ }
}
}
EXPORT_SYMBOL_GPL(__gmap_zap);
--
2.31.1
next prev parent reply other threads:[~2021-09-09 15:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 14:59 [PATCH RFC 0/9] s390: fixes, cleanups and optimizations for page table walkers David Hildenbrand
2021-09-09 14:59 ` [PATCH RFC 1/9] s390/gmap: validate VMA in __gmap_zap() David Hildenbrand
2021-09-09 14:59 ` David Hildenbrand [this message]
2021-09-09 14:59 ` [PATCH RFC 3/9] s390/mm: validate VMA in PGSTE manipulation functions David Hildenbrand
2021-09-09 14:59 ` [PATCH RFC 4/9] s390/mm: fix VMA and page table handling code in storage key handling functions David Hildenbrand
2021-09-09 14:59 ` [PATCH RFC 5/9] s390/uv: fully validate the VMA before calling follow_page() David Hildenbrand
2021-09-10 14:14 ` Liam Howlett
2021-09-09 14:59 ` [PATCH RFC 6/9] s390/pci_mmio: fully validate the VMA before calling follow_pte() David Hildenbrand
2021-09-10 8:22 ` Niklas Schnelle
2021-09-10 9:23 ` David Hildenbrand
2021-09-10 12:48 ` Niklas Schnelle
2021-09-10 14:12 ` Liam Howlett
2021-09-10 14:31 ` Niklas Schnelle
2021-09-10 14:52 ` Liam Howlett
2021-09-09 14:59 ` [PATCH RFC 7/9] s390/mm: no need for pte_alloc_map_lock() if we know the pmd is present David Hildenbrand
2021-09-09 14:59 ` [PATCH RFC 8/9] s390/mm: optimize set_guest_storage_key() David Hildenbrand
2021-09-09 14:59 ` [PATCH RFC 9/9] s390/mm: optimize reset_guest_reference_bit() David Hildenbrand
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