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authorSean Christopherson <sean.j.christopherson@intel.com>2019-04-12 19:55:41 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2019-04-15 13:25:07 +0200
commitcfd32acf7875d9dd83f82e1940098e88abeea439 (patch)
treef368804b0014edabdbc9e1bbfef00533d51cb36c /arch/x86/kvm/mmu.c
parent771acc7e4a6e5dba779cb1a7fd851a164bc81033 (diff)
downloadlinux-cfd32acf7875d9dd83f82e1940098e88abeea439.tar.bz2
KVM: x86/mmu: Fix an inverted list_empty() check when zapping sptes
A recently introduced helper for handling zap vs. remote flush incorrectly bails early, effectively leaking defunct shadow pages. Manifests as a slab BUG when exiting KVM due to the shadow pages being alive when their associated cache is destroyed. ========================================================================== BUG kvm_mmu_page_header: Objects remaining in kvm_mmu_page_header on ... -------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: Slab 0x00000000fc436387 objects=26 used=23 fp=0x00000000d023caee ... CPU: 6 PID: 4315 Comm: rmmod Tainted: G B 5.1.0-rc2+ #19 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack+0x46/0x5b slab_err+0xad/0xd0 ? on_each_cpu_mask+0x3c/0x50 ? ksm_migrate_page+0x60/0x60 ? on_each_cpu_cond_mask+0x7c/0xa0 ? __kmalloc+0x1ca/0x1e0 __kmem_cache_shutdown+0x13a/0x310 shutdown_cache+0xf/0x130 kmem_cache_destroy+0x1d5/0x200 kvm_mmu_module_exit+0xa/0x30 [kvm] kvm_arch_exit+0x45/0x60 [kvm] kvm_exit+0x6f/0x80 [kvm] vmx_exit+0x1a/0x50 [kvm_intel] __x64_sys_delete_module+0x153/0x1f0 ? exit_to_usermode_loop+0x88/0xc0 do_syscall_64+0x4f/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: a21136345cb6f ("KVM: x86/mmu: Split remote_flush+zap case out of kvm_mmu_flush_or_zap()") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
-rw-r--r--arch/x86/kvm/mmu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index eee455a8a612..85f753728953 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2238,7 +2238,7 @@ static bool kvm_mmu_remote_flush_or_zap(struct kvm *kvm,
struct list_head *invalid_list,
bool remote_flush)
{
- if (!remote_flush && !list_empty(invalid_list))
+ if (!remote_flush && list_empty(invalid_list))
return false;
if (!list_empty(invalid_list))