diff options
| author | Claudio Imbrenda <imbrenda@linux.ibm.com> | 2026-03-03 20:52:06 +0300 |
|---|---|---|
| committer | Claudio Imbrenda <imbrenda@linux.ibm.com> | 2026-03-06 14:41:28 +0300 |
| commit | f303406efd0b6b8740ce5c47e852097bbcf54879 (patch) | |
| tree | 528d57fd183257dc141741ba14e96ebaf33a23f7 | |
| parent | 5ee8dbf54602dc340d6235b1d6aa17c0f283f48c (diff) | |
| download | linux-f303406efd0b6b8740ce5c47e852097bbcf54879.tar.xz | |
KVM: s390: Fix a deadlock
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.
Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")
Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
| -rw-r--r-- | arch/s390/kvm/gaccess.c | 6 |
1 files 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); |