[PATCH v1 01/11] KVM: s390: Properly handle NULL pointer in dat_cond_set_storage_key()
Claudio Imbrenda <[email protected]>
| Newsgroups | org.kernel.vger.linux-s390,org.kernel.vger.kvm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Some callers pass NULL as oldkey. Calling page_cond_set_storage_key()
will cause that NULL pointer to get dereferenced.
Fix by checking for NULL and assigning the pointer to a dummy local
variable to avoid crashes.
Fixes: 8e03e8316eb2 ("KVM: s390: KVM page table management functions: storage keys")
Signed-off-by: Claudio Imbrenda <[email protected]>
---
arch/s390/kvm/dat.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c
index 3f2d6e8902d7..165c704fcf29 100644
--- a/arch/s390/kvm/dat.c
+++ b/arch/s390/kvm/dat.c
@@ -722,9 +722,12 @@ int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gf
if (rc)
return rc;
- if (!ptep)
+ if (!ptep) {
+ if (!oldkey)
+ oldkey = &prev;
return page_cond_set_storage_key(large_crste_to_phys(*crstep, gfn), skey, oldkey,
nq, mr, mc);
+ }
old = pgste_get_lock(ptep);
pgste = old;
--
2.55.0