From: punixcorn <ohyunwoods663@gmail.com>
To: seanjc@google.com, pbonzini@redhat.com
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [BUG] KVM: NULL pointer dereference in kvm_tdp_mmu_map under memory pressure
Date: Wed, 8 Apr 2026 11:21:13 +0000 [thread overview]
Message-ID: <20260408112113.183989-1-ohyunwoods663@gmail.com> (raw)
In-Reply-To: <20260408102914.106838-1-ohyunwoods663@gmail.com>
Following up with additional analysis from gdb.
The crash is at spte.h:263 in to_shadow_page(), not at the
tdp_mmu_alloc_sp() path as initially suspected.
(gdb) list *(kvm_tdp_mmu_map+0x471)
0x79451 is in kvm_tdp_mmu_map (mmu/spte.h:263)
return (struct kvm_mmu_page *)page_private(page);
The crash location suggests page_private() is returning 0 for the
parent shadow page in tdp_mmu_init_child_sp(). The exact cause is
unclear. Sharing for maintainer review.
My earlier speculative fix (checking sp == NULL) was incorrect.
I am not familiar enough with the KVM MMU internals to propose a
correct fix. Sharing this in case it helps maintainers narrow down
the root cause.
next prev parent reply other threads:[~2026-04-08 11:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-08 10:29 punixcorn
2026-04-08 11:21 ` punixcorn [this message]
2026-04-08 14:18 ` Sean Christopherson
[not found] <202604081418.sean.christopherson@intel.com>
2026-04-08 15:36 ` punixcorn
2026-04-08 16:33 ` Sean Christopherson
[not found] <202604081633.sean.christopherson@intel.com>
2026-04-08 18:43 ` punixcorn
2026-04-13 21:47 ` Sean Christopherson
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