KVM: s390: vsie: Avoid potential deadlock with real spaces

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The natural lock ordering is mmu_lock -> children_lock, but in
gmap_create_shadow() the reverse order is used when handling shadowing
of real address spaces.

Convert the inner locking of kvm->mmu_lock to a trylock; return -EAGAIN
if the lock is busy, and let the caller try again.

This path is not expected to happen in real-life scenarios, so its
performance is not important.

Fixes: a2c17f9270 ("KVM: s390: New gmap code")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

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Claudio Imbrenda 2026-07-02 17:23:59 +02:00 • committed by Christian Borntraeger

parent 7b69729046

commit 866d03de6d

1 changed files with 6 additions and 1 deletions

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arch/s390/kvm/gmap.c

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