In some scenarios, a deadlock can happen, involving _do_shadow_pte(). Convert all usages of pgste_get_lock() to pgste_get_trylock() in _do_shadow_pte() and return -EAGAIN. All callers can already deal with -EAGAIN being returned. Signed-off-by: Claudio Imbrenda Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") --- arch/s390/kvm/gaccess.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 4630b2a067ea..a9da9390867d 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -1434,7 +1434,8 @@ static int _do_shadow_pte(struct gmap *sg, gpa_t raddr, union pte *ptep_h, union if (rc) return rc; - pgste = pgste_get_lock(ptep_h); + if (!pgste_get_trylock(ptep_h, &pgste)) + return -EAGAIN; newpte = _pte(f->pfn, f->writable, !p, 0); newpte.s.d |= ptep->s.d; newpte.s.sd |= ptep->s.sd; @@ -1444,7 +1445,8 @@ static int _do_shadow_pte(struct gmap *sg, gpa_t raddr, union pte *ptep_h, union pgste_set_unlock(ptep_h, pgste); newpte = _pte(f->pfn, 0, !p, 0); - pgste = pgste_get_lock(ptep); + if (!pgste_get_trylock(ptep, &pgste)) + return -EAGAIN; pgste = __dat_ptep_xchg(ptep, pgste, newpte, gpa_to_gfn(raddr), sg->asce, uses_skeys(sg)); pgste_set_unlock(ptep, pgste); -- 2.53.0