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authorHeiko Carstens <hca@linux.ibm.com>2020-09-07 17:11:36 +0200
committerVasily Gorbik <gor@linux.ibm.com>2020-09-14 11:38:34 +0200
commit36c2733c439caa424fe2b7dded870913dcb868ac (patch)
tree8846d2fa2c940d00b92e1bbc08681951c57317d1
parent9d719d39aab41d3b8b6f259574dc29a27f60e66c (diff)
s390/mm,ptdump: hold memory hotplug lock while walking for kernel page table dump
This is the s390 variant of commit bf2b59f60ee1 ("arm64/mm: Hold memory hotplug lock while walking for kernel page table dump"). Right now this doesn't fix any real bug, however as soon as kvm patches get merged which make use of memory remove we might end up dereferencing/accessing freed page tables. Therefore fix this potential bug already now. Reviewed-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
-rw-r--r--arch/s390/mm/dump_pagetables.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c
index 93a29e2f13d4..3c5e4055a3d2 100644
--- a/arch/s390/mm/dump_pagetables.c
+++ b/arch/s390/mm/dump_pagetables.c
@@ -129,7 +129,9 @@ static int ptdump_show(struct seq_file *m, void *v)
.marker = address_markers,
};
+ get_online_mems();
ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
+ put_online_mems();
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ptdump);