arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_change_pte' - different lock contexts for basic block

arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_change_pte' - different lock contexts for basic block

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
CC: linux-kernel(a)vger.kernel.org
TO: Sean Christopherson <seanjc@google.com>
CC: Paolo Bonzini <pbonzini@redhat.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   cd1245d75ce93b8fd206f4b34eb58bcfe156d5e9
commit: 8931a454aea03bab21b3b8fcdc94f674eebd1c5d KVM: Take mmu_lock when handling MMU notifier iff the hva hits a memslot
date:   8 weeks ago
:::::: branch date: 15 hours ago
:::::: commit date: 8 weeks ago
config: mips-randconfig-s031-20210610 (attached as .config)
compiler: mipsel-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-341-g8af24329-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8931a454aea03bab21b3b8fcdc94f674eebd1c5d
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 8931a454aea03bab21b3b8fcdc94f674eebd1c5d
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
   command-line: note: in included file:
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_ACQUIRE redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_SEQ_CST redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_ACQ_REL redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_RELEASE redefined
   builtin:0:0: sparse: this was the original definition
>> arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_change_pte' - different lock contexts for basic block
>> arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_invalidate_range_start' - different lock contexts for basic block
>> arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_invalidate_range_end' - different lock contexts for basic block
>> arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_clear_flush_young' - different lock contexts for basic block
>> arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_clear_young' - different lock contexts for basic block
>> arch/mips/kvm/../../../virt/kvm/kvm_main.c:541:25: sparse: sparse: context imbalance in 'kvm_mmu_notifier_test_young' - different lock contexts for basic block
   arch/mips/kvm/../../../virt/kvm/kvm_main.c:2110:9: sparse: sparse: context imbalance in 'hva_to_pfn_remapped' - unexpected unlock

vim +/kvm_mmu_notifier_change_pte +541 arch/mips/kvm/../../../virt/kvm/kvm_main.c

f922bd9bf33bd5 Sean Christopherson 2021-04-01  481  
3039bcc744980a Sean Christopherson 2021-04-01  482  static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
3039bcc744980a Sean Christopherson 2021-04-01  483  						  const struct kvm_hva_range *range)
3039bcc744980a Sean Christopherson 2021-04-01  484  {
8931a454aea03b Sean Christopherson 2021-04-01  485  	bool ret = false, locked = false;
f922bd9bf33bd5 Sean Christopherson 2021-04-01  486  	struct kvm_gfn_range gfn_range;
3039bcc744980a Sean Christopherson 2021-04-01  487  	struct kvm_memory_slot *slot;
3039bcc744980a Sean Christopherson 2021-04-01  488  	struct kvm_memslots *slots;
3039bcc744980a Sean Christopherson 2021-04-01  489  	int i, idx;
3039bcc744980a Sean Christopherson 2021-04-01  490  
f922bd9bf33bd5 Sean Christopherson 2021-04-01  491  	/* A null handler is allowed if and only if on_lock() is provided. */
f922bd9bf33bd5 Sean Christopherson 2021-04-01  492  	if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) &&
f922bd9bf33bd5 Sean Christopherson 2021-04-01  493  			 IS_KVM_NULL_FN(range->handler)))
f922bd9bf33bd5 Sean Christopherson 2021-04-01  494  		return 0;
f922bd9bf33bd5 Sean Christopherson 2021-04-01  495  
3039bcc744980a Sean Christopherson 2021-04-01  496  	idx = srcu_read_lock(&kvm->srcu);
3039bcc744980a Sean Christopherson 2021-04-01  497  
8931a454aea03b Sean Christopherson 2021-04-01  498  	/* The on_lock() path does not yet support lock elision. */
f922bd9bf33bd5 Sean Christopherson 2021-04-01  499  	if (!IS_KVM_NULL_FN(range->on_lock)) {
8931a454aea03b Sean Christopherson 2021-04-01  500  		locked = true;
8931a454aea03b Sean Christopherson 2021-04-01  501  		KVM_MMU_LOCK(kvm);
8931a454aea03b Sean Christopherson 2021-04-01  502  
f922bd9bf33bd5 Sean Christopherson 2021-04-01  503  		range->on_lock(kvm, range->start, range->end);
f922bd9bf33bd5 Sean Christopherson 2021-04-01  504  
f922bd9bf33bd5 Sean Christopherson 2021-04-01  505  		if (IS_KVM_NULL_FN(range->handler))
f922bd9bf33bd5 Sean Christopherson 2021-04-01  506  			goto out_unlock;
f922bd9bf33bd5 Sean Christopherson 2021-04-01  507  	}
f922bd9bf33bd5 Sean Christopherson 2021-04-01  508  
3039bcc744980a Sean Christopherson 2021-04-01  509  	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
3039bcc744980a Sean Christopherson 2021-04-01  510  		slots = __kvm_memslots(kvm, i);
3039bcc744980a Sean Christopherson 2021-04-01  511  		kvm_for_each_memslot(slot, slots) {
3039bcc744980a Sean Christopherson 2021-04-01  512  			unsigned long hva_start, hva_end;
3039bcc744980a Sean Christopherson 2021-04-01  513  
3039bcc744980a Sean Christopherson 2021-04-01  514  			hva_start = max(range->start, slot->userspace_addr);
3039bcc744980a Sean Christopherson 2021-04-01  515  			hva_end = min(range->end, slot->userspace_addr +
3039bcc744980a Sean Christopherson 2021-04-01  516  						  (slot->npages << PAGE_SHIFT));
3039bcc744980a Sean Christopherson 2021-04-01  517  			if (hva_start >= hva_end)
3039bcc744980a Sean Christopherson 2021-04-01  518  				continue;
3039bcc744980a Sean Christopherson 2021-04-01  519  
3039bcc744980a Sean Christopherson 2021-04-01  520  			/*
3039bcc744980a Sean Christopherson 2021-04-01  521  			 * To optimize for the likely case where the address
3039bcc744980a Sean Christopherson 2021-04-01  522  			 * range is covered by zero or one memslots, don't
3039bcc744980a Sean Christopherson 2021-04-01  523  			 * bother making these conditional (to avoid writes on
3039bcc744980a Sean Christopherson 2021-04-01  524  			 * the second or later invocation of the handler).
3039bcc744980a Sean Christopherson 2021-04-01  525  			 */
3039bcc744980a Sean Christopherson 2021-04-01  526  			gfn_range.pte = range->pte;
3039bcc744980a Sean Christopherson 2021-04-01  527  			gfn_range.may_block = range->may_block;
3039bcc744980a Sean Christopherson 2021-04-01  528  
3039bcc744980a Sean Christopherson 2021-04-01  529  			/*
3039bcc744980a Sean Christopherson 2021-04-01  530  			 * {gfn(page) | page intersects with [hva_start, hva_end)} =
3039bcc744980a Sean Christopherson 2021-04-01  531  			 * {gfn_start, gfn_start+1, ..., gfn_end-1}.
3039bcc744980a Sean Christopherson 2021-04-01  532  			 */
3039bcc744980a Sean Christopherson 2021-04-01  533  			gfn_range.start = hva_to_gfn_memslot(hva_start, slot);
3039bcc744980a Sean Christopherson 2021-04-01  534  			gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot);
3039bcc744980a Sean Christopherson 2021-04-01  535  			gfn_range.slot = slot;
3039bcc744980a Sean Christopherson 2021-04-01  536  
8931a454aea03b Sean Christopherson 2021-04-01  537  			if (!locked) {
8931a454aea03b Sean Christopherson 2021-04-01  538  				locked = true;
8931a454aea03b Sean Christopherson 2021-04-01  539  				KVM_MMU_LOCK(kvm);
8931a454aea03b Sean Christopherson 2021-04-01  540  			}
3039bcc744980a Sean Christopherson 2021-04-01 @541  			ret |= range->handler(kvm, &gfn_range);
3039bcc744980a Sean Christopherson 2021-04-01  542  		}
3039bcc744980a Sean Christopherson 2021-04-01  543  	}
3039bcc744980a Sean Christopherson 2021-04-01  544  
3039bcc744980a Sean Christopherson 2021-04-01  545  	if (range->flush_on_ret && (ret || kvm->tlbs_dirty))
3039bcc744980a Sean Christopherson 2021-04-01  546  		kvm_flush_remote_tlbs(kvm);
3039bcc744980a Sean Christopherson 2021-04-01  547  
f922bd9bf33bd5 Sean Christopherson 2021-04-01  548  out_unlock:
8931a454aea03b Sean Christopherson 2021-04-01  549  	if (locked)
f922bd9bf33bd5 Sean Christopherson 2021-04-01  550  		KVM_MMU_UNLOCK(kvm);
f922bd9bf33bd5 Sean Christopherson 2021-04-01  551  
3039bcc744980a Sean Christopherson 2021-04-01  552  	srcu_read_unlock(&kvm->srcu, idx);
3039bcc744980a Sean Christopherson 2021-04-01  553  
3039bcc744980a Sean Christopherson 2021-04-01  554  	/* The notifiers are averse to booleans. :-( */
3039bcc744980a Sean Christopherson 2021-04-01  555  	return (int)ret;
3039bcc744980a Sean Christopherson 2021-04-01  556  }
3039bcc744980a Sean Christopherson 2021-04-01  557  

:::::: The code at line 541 was first introduced by commit
:::::: 3039bcc744980afe87c612122e47a27306483bc2 KVM: Move x86's MMU notifier memslot walkers to generic code

:::::: TO: Sean Christopherson <seanjc@google.com>
:::::: CC: Paolo Bonzini <pbonzini@redhat.com>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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