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KVM: s390: Properly handle NULL pointer in dat_cond_set_storage_key()

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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: 8e03e8316e ("KVM: s390: KVM page table management functions: storage keys")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260812104436.109741-2-imbrenda@linux.ibm.com>
This commit is contained in:
Claudio Imbrenda 2026-08-12 12:44:28 +02:00
parent c44d36d8e6
commit 88e22ffd1e
1 changed files with 4 additions and 1 deletions
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5
arch/s390/kvm/dat.c
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@ -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;