korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 12:28:41 +08:00
Code Issues Packages Projects Releases Wiki Activity

s390/gmap: don't unconditionally call pte_unmap_unlock() in __gmap_zap()

Browse Source 
[ Upstream commit b159f94c86 ]

... 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: 1e133ab296 ("s390/mm: split arch/s390/mm/pgtable.c")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20210909162248.14969-3-david@redhat.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
David Hildenbrand 2021-09-09 18:22:41 +02:00 committed by Greg Kroah-Hartman
parent f85450ca01
commit 3ad3017290
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/s390/mm/gmap.c
View File

@ -684,9 +684,10 @@ void __gmap_zap(struct gmap *gmap, unsigned long gaddr)
vmaddr |= gaddr & ~PMD_MASK;
/* 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);