prdoc/pr_3865.prdoc

+title: "Balances: add failsafe for consumer ref underflow"
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      Pallet balances now handles the case that historic accounts violate a invariant that they should have a consumer ref on `reserved > 0` balance.  
+      This disallows such accounts from reaping and should prevent TI from getting messed up even more.
+
+crates:
+  - name: pallet-balances
+    bump: patch

prdoc/pr_4175.prdoc

+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: "Snowbridge: deposit extra fee to beneficiary on Asset Hub"
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      Snowbridge transfers arriving on Asset Hub will deposit both asset and fees to beneficiary so the fees will not get trapped. 
+      Another benefit is when fees left more than ED, could be used to create the beneficiary account in case it does not exist on asset hub.
+
+crates:
+  - name: snowbridge-router-primitives

substrate/bin/node/runtime/src/lib.rs

@@ -654,7 +654,6 @@ parameter_types! {
 	pub const SlashDeferDuration: sp_staking::EraIndex = 24 * 7; // 1/4 the bonding duration.
 	pub const RewardCurve: &'static PiecewiseLinear<'static> = &REWARD_CURVE;
 	pub const MaxNominators: u32 = 64;
-	pub const OffendingValidatorsThreshold: Perbill = Perbill::from_percent(17);
 	pub const MaxControllersInDeprecationBatch: u32 = 5900;
 	pub OffchainRepeat: BlockNumber = 5;
 	pub HistoryDepth: u32 = 84;
@@ -690,7 +689,6 @@ impl pallet_staking::Config for Runtime {
 	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = Session;
 	type MaxExposurePageSize = ConstU32<256>;
-	type OffendingValidatorsThreshold = OffendingValidatorsThreshold;
 	type ElectionProvider = ElectionProviderMultiPhase;
 	type GenesisElectionProvider = onchain::OnChainExecution<OnChainSeqPhragmen>;
 	type VoterList = VoterList;
@@ -703,6 +701,7 @@ impl pallet_staking::Config for Runtime {
 	type EventListeners = NominationPools;
 	type WeightInfo = pallet_staking::weights::SubstrateWeight<Runtime>;
 	type BenchmarkingConfig = StakingBenchmarkingConfig;
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 impl pallet_fast_unstake::Config for Runtime {

substrate/client/consensus/manual-seal/src/lib.rs

@@ -86,7 +86,7 @@ where
 	BasicQueue::new(ManualSealVerifier, block_import, None, spawner, registry)
 }
 
-/// Params required to start the instant sealing authorship task.
+/// Params required to start the manual sealing authorship task.
 pub struct ManualSealParams<B: BlockT, BI, E, C: ProvideRuntimeApi<B>, TP, SC, CS, CIDP, P> {
 	/// Block import instance.
 	pub block_import: BI,
@@ -114,7 +114,7 @@ pub struct ManualSealParams<B: BlockT, BI, E, C: ProvideRuntimeApi<B>, TP, SC, C
 	pub create_inherent_data_providers: CIDP,
 }
 
-/// Params required to start the manual sealing authorship task.
+/// Params required to start the instant sealing authorship task.
 pub struct InstantSealParams<B: BlockT, BI, E, C: ProvideRuntimeApi<B>, TP, SC, CIDP, P> {
 	/// Block import instance for well. importing blocks.
 	pub block_import: BI,

substrate/frame/babe/src/mock.rs

@@ -144,7 +144,6 @@ parameter_types! {
 	pub const BondingDuration: EraIndex = 3;
 	pub const SlashDeferDuration: EraIndex = 0;
 	pub const RewardCurve: &'static PiecewiseLinear<'static> = &REWARD_CURVE;
-	pub const OffendingValidatorsThreshold: Perbill = Perbill::from_percent(16);
 	pub static ElectionsBounds: ElectionBounds = ElectionBoundsBuilder::default().build();
 }
 
@@ -174,7 +173,6 @@ impl pallet_staking::Config for Test {
 	type UnixTime = pallet_timestamp::Pallet<Test>;
 	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type MaxExposurePageSize = ConstU32<64>;
-	type OffendingValidatorsThreshold = OffendingValidatorsThreshold;
 	type NextNewSession = Session;
 	type ElectionProvider = onchain::OnChainExecution<OnChainSeqPhragmen>;
 	type GenesisElectionProvider = Self::ElectionProvider;
@@ -187,6 +185,7 @@ impl pallet_staking::Config for Test {
 	type EventListeners = ();
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
 	type WeightInfo = ();
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 impl pallet_offences::Config for Test {

substrate/frame/balances/Cargo.toml

@@ -28,6 +28,7 @@ docify = "0.2.8"
 
 [dev-dependencies]
 pallet-transaction-payment = { path = "../transaction-payment" }
+frame-support = { path = "../support", features = ["experimental"] }
 sp-core = { path = "../../primitives/core" }
 sp-io = { path = "../../primitives/io" }
 paste = "1.0.12"

substrate/frame/balances/src/lib.rs

@@ -954,6 +954,13 @@ pub mod pallet {
 				if !did_consume && does_consume {
 					frame_system::Pallet::<T>::inc_consumers(who)?;
 				}
+				if does_consume && frame_system::Pallet::<T>::consumers(who) == 0 {
+					// NOTE: This is a failsafe and should not happen for normal accounts. A normal
+					// account should have gotten a consumer ref in `!did_consume && does_consume`
+					// at some point.
+					log::error!(target: LOG_TARGET, "Defensively bumping a consumer ref.");
+					frame_system::Pallet::<T>::inc_consumers(who)?;
+				}
 				if did_provide && !does_provide {
 					// This could reap the account so must go last.
 					frame_system::Pallet::<T>::dec_providers(who).map_err(|r| {

substrate/frame/balances/src/tests/general_tests.rs

+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![cfg(test)]
+
+use crate::{
+	system::AccountInfo,
+	tests::{ensure_ti_valid, Balances, ExtBuilder, System, Test, TestId, UseSystem},
+	AccountData, ExtraFlags, TotalIssuance,
+};
+use frame_support::{
+	assert_noop, assert_ok, hypothetically,
+	traits::{
+		fungible::{Mutate, MutateHold},
+		tokens::Precision,
+	},
+};
+use sp_runtime::DispatchError;
+
+/// There are some accounts that have one consumer ref too few. These accounts are at risk of losing
+/// their held (reserved) balance. They do not just lose it - it is also not accounted for in the
+/// Total Issuance. Here we test the case that the account does not reap in such a case, but gets
+/// one consumer ref for its reserved balance.
+#[test]
+fn regression_historic_acc_does_not_evaporate_reserve() {
+	ExtBuilder::default().build_and_execute_with(|| {
+		UseSystem::set(true);
+		let (alice, bob) = (0, 1);
+		// Alice is in a bad state with consumer == 0 && reserved > 0:
+		Balances::set_balance(&alice, 100);
+		TotalIssuance::<Test>::put(100);
+		ensure_ti_valid();
+
+		assert_ok!(Balances::hold(&TestId::Foo, &alice, 10));
+		// This is the issue of the account:
+		System::dec_consumers(&alice);
+
+		assert_eq!(
+			System::account(&alice),
+			AccountInfo {
+				data: AccountData {
+					free: 90,
+					reserved: 10,
+					frozen: 0,
+					flags: ExtraFlags(1u128 << 127),
+				},
+				nonce: 0,
+				consumers: 0, // should be 1 on a good acc
+				providers: 1,
+				sufficients: 0,
+			}
+		);
+
+		ensure_ti_valid();
+
+		// Reaping the account is prevented by the new logic:
+		assert_noop!(
+			Balances::transfer_allow_death(Some(alice).into(), bob, 90),
+			DispatchError::ConsumerRemaining
+		);
+		assert_noop!(
+			Balances::transfer_all(Some(alice).into(), bob, false),
+			DispatchError::ConsumerRemaining
+		);
+
+		// normal transfers still work:
+		hypothetically!({
+			assert_ok!(Balances::transfer_keep_alive(Some(alice).into(), bob, 40));
+			// Alice got back her consumer ref:
+			assert_eq!(System::consumers(&alice), 1);
+			ensure_ti_valid();
+		});
+		hypothetically!({
+			assert_ok!(Balances::transfer_all(Some(alice).into(), bob, true));
+			// Alice got back her consumer ref:
+			assert_eq!(System::consumers(&alice), 1);
+			ensure_ti_valid();
+		});
+
+		// un-reserving all does not add a consumer ref:
+		hypothetically!({
+			assert_ok!(Balances::release(&TestId::Foo, &alice, 10, Precision::Exact));
+			assert_eq!(System::consumers(&alice), 0);
+			assert_ok!(Balances::transfer_keep_alive(Some(alice).into(), bob, 40));
+			assert_eq!(System::consumers(&alice), 0);
+			ensure_ti_valid();
+		});
+		// un-reserving some does add a consumer ref:
+		hypothetically!({
+			assert_ok!(Balances::release(&TestId::Foo, &alice, 5, Precision::Exact));
+			assert_eq!(System::consumers(&alice), 1);
+			assert_ok!(Balances::transfer_keep_alive(Some(alice).into(), bob, 40));
+			assert_eq!(System::consumers(&alice), 1);
+			ensure_ti_valid();
+		});
+	});
+}

substrate/frame/balances/src/tests/mod.rs

@@ -19,7 +19,7 @@
 
 #![cfg(test)]
 
-use crate::{self as pallet_balances, AccountData, Config, CreditOf, Error, Pallet};
+use crate::{self as pallet_balances, AccountData, Config, CreditOf, Error, Pallet, TotalIssuance};
 use codec::{Decode, Encode, MaxEncodedLen};
 use frame_support::{
 	assert_err, assert_noop, assert_ok, assert_storage_noop, derive_impl,
@@ -47,6 +47,7 @@ mod currency_tests;
 mod dispatchable_tests;
 mod fungible_conformance_tests;
 mod fungible_tests;
+mod general_tests;
 mod reentrancy_tests;
 
 type Block = frame_system::mocking::MockBlock<Test>;
@@ -278,6 +279,23 @@ pub fn info_from_weight(w: Weight) -> DispatchInfo {
 	DispatchInfo { weight: w, ..Default::default() }
 }
 
+/// Check that the total-issuance matches the sum of all accounts' total balances.
+pub fn ensure_ti_valid() {
+	let mut sum = 0;
+
+	for acc in frame_system::Account::<Test>::iter_keys() {
+		if UseSystem::get() {
+			let data = frame_system::Pallet::<Test>::account(acc);
+			sum += data.data.total();
+		} else {
+			let data = crate::Account::<Test>::get(acc);
+			sum += data.total();
+		}
+	}
+
+	assert_eq!(TotalIssuance::<Test>::get(), sum, "Total Issuance wrong");
+}
+
 #[test]
 fn weights_sane() {
 	let info = crate::Call::<Test>::transfer_allow_death { dest: 10, value: 4 }.get_dispatch_info();

substrate/frame/balances/src/types.rs

@@ -111,7 +111,7 @@ pub struct AccountData<Balance> {
 const IS_NEW_LOGIC: u128 = 0x80000000_00000000_00000000_00000000u128;
 
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, MaxEncodedLen, TypeInfo)]
-pub struct ExtraFlags(u128);
+pub struct ExtraFlags(pub(crate) u128);
 impl Default for ExtraFlags {
 	fn default() -> Self {
 		Self(IS_NEW_LOGIC)

substrate/frame/beefy/src/mock.rs

@@ -158,7 +158,6 @@ parameter_types! {
 	pub const SessionsPerEra: SessionIndex = 3;
 	pub const BondingDuration: EraIndex = 3;
 	pub const RewardCurve: &'static PiecewiseLinear<'static> = &REWARD_CURVE;
-	pub const OffendingValidatorsThreshold: Perbill = Perbill::from_percent(17);
 	pub static ElectionsBoundsOnChain: ElectionBounds = ElectionBoundsBuilder::default().build();
 }
 
@@ -188,7 +187,6 @@ impl pallet_staking::Config for Test {
 	type UnixTime = pallet_timestamp::Pallet<Test>;
 	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type MaxExposurePageSize = ConstU32<64>;
-	type OffendingValidatorsThreshold = OffendingValidatorsThreshold;
 	type NextNewSession = Session;
 	type ElectionProvider = onchain::OnChainExecution<OnChainSeqPhragmen>;
 	type GenesisElectionProvider = Self::ElectionProvider;
@@ -201,6 +199,7 @@ impl pallet_staking::Config for Test {
 	type EventListeners = ();
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
 	type WeightInfo = ();
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 impl pallet_offences::Config for Test {

substrate/frame/election-provider-multi-phase/test-staking-e2e/src/lib.rs

@@ -23,7 +23,6 @@ pub(crate) const LOG_TARGET: &str = "tests::e2e-epm";
 use frame_support::{assert_err, assert_noop, assert_ok};
 use mock::*;
 use sp_core::Get;
-use sp_npos_elections::{to_supports, StakedAssignment};
 use sp_runtime::Perbill;
 
 use crate::mock::RuntimeOrigin;
@@ -127,75 +126,48 @@ fn offchainify_works() {
 }
 
 #[test]
-/// Replicates the Kusama incident of 8th Dec 2022 and its resolution through the governance
+/// Inspired by the Kusama incident of 8th Dec 2022 and its resolution through the governance
 /// fallback.
 ///
-/// After enough slashes exceeded the `Staking::OffendingValidatorsThreshold`, the staking pallet
-/// set `Forcing::ForceNew`. When a new session starts, staking will start to force a new era and
-/// calls <EPM as election_provider>::elect(). If at this point EPM and the staking miners did not
-/// have enough time to queue a new solution (snapshot + solution submission), the election request
-/// fails. If there is no election fallback mechanism in place, EPM enters in emergency mode.
-/// Recovery: Once EPM is in emergency mode, subsequent calls to `elect()` will fail until a new
-/// solution is added to EPM's `QueuedSolution` queue. This can be achieved through
-/// `Call::set_emergency_election_result` or `Call::governance_fallback` dispatchables. Once a new
-/// solution is added to the queue, EPM phase transitions to `Phase::Off` and the election flow
-/// restarts. Note that in this test case, the emergency throttling is disabled.
-fn enters_emergency_phase_after_forcing_before_elect() {
+/// Mass slash of validators shouldn't disable more than 1/3 of them (the byzantine threshold). Also
+/// no new era should be forced which could lead to EPM entering emergency mode.
+fn mass_slash_doesnt_enter_emergency_phase() {
 	let epm_builder = EpmExtBuilder::default().disable_emergency_throttling();
-	let (ext, pool_state, _) = ExtBuilder::default().epm(epm_builder).build_offchainify();
-
-	execute_with(ext, || {
-		log!(
-			trace,
-			"current validators (staking): {:?}",
-			<Runtime as pallet_staking::SessionInterface<AccountId>>::validators()
-		);
-		let session_validators_before = Session::validators();
-
-		roll_to_epm_off();
-		assert!(ElectionProviderMultiPhase::current_phase().is_off());
+	let staking_builder = StakingExtBuilder::default().validator_count(7);
+	let (mut ext, _, _) = ExtBuilder::default()
+		.epm(epm_builder)
+		.staking(staking_builder)
+		.build_offchainify();
 
+	ext.execute_with(|| {
 		assert_eq!(pallet_staking::ForceEra::<Runtime>::get(), pallet_staking::Forcing::NotForcing);
-		// slashes so that staking goes into `Forcing::ForceNew`.
-		slash_through_offending_threshold();
 
-		assert_eq!(pallet_staking::ForceEra::<Runtime>::get(), pallet_staking::Forcing::ForceNew);
+		let active_set_size_before_slash = Session::validators().len();
 
-		advance_session_delayed_solution(pool_state.clone());
-		assert!(ElectionProviderMultiPhase::current_phase().is_emergency());
-		log_current_time();
+		// Slash more than 1/3 of the active validators
+		let mut slashed = slash_half_the_active_set();
 
-		let era_before_delayed_next = Staking::current_era();
-		// try to advance 2 eras.
-		assert!(start_next_active_era_delayed_solution(pool_state.clone()).is_ok());
-		assert_eq!(Staking::current_era(), era_before_delayed_next);
-		assert!(start_next_active_era(pool_state).is_err());
-		assert_eq!(Staking::current_era(), era_before_delayed_next);
+		let active_set_size_after_slash = Session::validators().len();
 
-		// EPM is still in emergency phase.
-		assert!(ElectionProviderMultiPhase::current_phase().is_emergency());
+		// active set should stay the same before and after the slash
+		assert_eq!(active_set_size_before_slash, active_set_size_after_slash);
 
-		// session validator set remains the same.
-		assert_eq!(Session::validators(), session_validators_before);
-
-		// performs recovery through the set emergency result.
-		let supports = to_supports(&vec![
-			StakedAssignment { who: 21, distribution: vec![(21, 10)] },
-			StakedAssignment { who: 31, distribution: vec![(21, 10), (31, 10)] },
-			StakedAssignment { who: 41, distribution: vec![(41, 10)] },
-		]);
-		assert!(ElectionProviderMultiPhase::set_emergency_election_result(
-			RuntimeOrigin::root(),
-			supports
-		)
-		.is_ok());
+		// Slashed validators are disabled up to a limit
+		slashed.truncate(
+			pallet_staking::UpToLimitDisablingStrategy::<SLASHING_DISABLING_FACTOR>::disable_limit(
+				active_set_size_after_slash,
+			),
+		);
 
-		// EPM can now roll to signed phase to proceed with elections. The validator set is the
-		// expected (ie. set through `set_emergency_election_result`).
-		roll_to_epm_signed();
-		//assert!(ElectionProviderMultiPhase::current_phase().is_signed());
-		assert_eq!(Session::validators(), vec![21, 31, 41]);
-		assert_eq!(Staking::current_era(), era_before_delayed_next.map(|e| e + 1));
+		// Find the indices of the disabled validators
+		let active_set = Session::validators();
+		let expected_disabled = slashed
+			.into_iter()
+			.map(|d| active_set.iter().position(|a| *a == d).unwrap() as u32)
+			.collect::<Vec<_>>();
+
+		assert_eq!(pallet_staking::ForceEra::<Runtime>::get(), pallet_staking::Forcing::NotForcing);
+		assert_eq!(Session::disabled_validators(), expected_disabled);
 	});
 }
 
@@ -253,77 +225,7 @@ fn continuous_slashes_below_offending_threshold() {
 }
 
 #[test]
-/// Slashed validator sets intentions in the same era of slashing.
-///
-/// When validators are slashed, they are chilled and removed from the current `VoterList`. Thus,
-/// the slashed validator should not be considered in the next validator set. However, if the
-/// slashed validator sets its intention to validate again in the same era when it was slashed and
-/// chilled, the validator may not be removed from the active validator set across eras, provided
-/// it would selected in the subsequent era if there was no slash. Nominators of the slashed
-/// validator will also be slashed and chilled, as expected, but the nomination intentions will
-/// remain after the validator re-set the intention to be validating again.
-///
-/// This behaviour is due to removing implicit chill upon slash
-/// <https://github.com/paritytech/substrate/pull/12420>.
-///
-/// Related to <https://github.com/paritytech/substrate/issues/13714>.
-fn set_validation_intention_after_chilled() {
-	use frame_election_provider_support::SortedListProvider;
-	use pallet_staking::{Event, Forcing, Nominators};
-
-	let (ext, pool_state, _) = ExtBuilder::default()
-		.epm(EpmExtBuilder::default())
-		.staking(StakingExtBuilder::default())
-		.build_offchainify();
-
-	execute_with(ext, || {
-		assert_eq!(active_era(), 0);
-		// validator is part of the validator set.
-		assert!(Session::validators().contains(&41));
-		assert!(<Runtime as pallet_staking::Config>::VoterList::contains(&41));
-
-		// nominate validator 81.
-		assert_ok!(Staking::nominate(RuntimeOrigin::signed(21), vec![41]));
-		assert_eq!(Nominators::<Runtime>::get(21).unwrap().targets, vec![41]);
-
-		// validator is slashed. it is removed from the `VoterList` through chilling but in the
-		// current era, the validator is still part of the active validator set.
-		add_slash(&41);
-		assert!(Session::validators().contains(&41));
-		assert!(!<Runtime as pallet_staking::Config>::VoterList::contains(&41));
-		assert_eq!(
-			staking_events(),
-			[
-				Event::Chilled { stash: 41 },
-				Event::ForceEra { mode: Forcing::ForceNew },
-				Event::SlashReported {
-					validator: 41,
-					slash_era: 0,
-					fraction: Perbill::from_percent(10)
-				}
-			],
-		);
-
-		// after the nominator is slashed and chilled, the nominations remain.
-		assert_eq!(Nominators::<Runtime>::get(21).unwrap().targets, vec![41]);
-
-		// validator sets intention to stake again in the same era it was chilled.
-		assert_ok!(Staking::validate(RuntimeOrigin::signed(41), Default::default()));
-
-		// progress era and check that the slashed validator is still part of the validator
-		// set.
-		assert!(start_next_active_era(pool_state).is_ok());
-		assert_eq!(active_era(), 1);
-		assert!(Session::validators().contains(&41));
-		assert!(<Runtime as pallet_staking::Config>::VoterList::contains(&41));
-
-		// nominations are still active as before the slash.
-		assert_eq!(Nominators::<Runtime>::get(21).unwrap().targets, vec![41]);
-	})
-}
-
-#[test]
-/// Active ledger balance may fall below ED if account chills before unbonding.
+/// Active ledger balance may fall below ED if account chills before unbounding.
 ///
 /// Unbonding call fails if the remaining ledger's stash balance falls below the existential
 /// deposit. However, if the stash is chilled before unbonding, the ledger's active balance may

substrate/frame/election-provider-multi-phase/test-staking-e2e/src/mock.rs

@@ -35,7 +35,7 @@ use sp_runtime::{
 	transaction_validity, BuildStorage, PerU16, Perbill, Percent,
 };
 use sp_staking::{
-	offence::{DisableStrategy, OffenceDetails, OnOffenceHandler},
+	offence::{OffenceDetails, OnOffenceHandler},
 	EraIndex, SessionIndex,
 };
 use sp_std::prelude::*;
@@ -236,7 +236,6 @@ parameter_types! {
 	pub const SessionsPerEra: sp_staking::SessionIndex = 2;
 	pub static BondingDuration: sp_staking::EraIndex = 28;
 	pub const SlashDeferDuration: sp_staking::EraIndex = 7; // 1/4 the bonding duration.
-	pub const OffendingValidatorsThreshold: Perbill = Perbill::from_percent(40);
 	pub HistoryDepth: u32 = 84;
 }
 
@@ -290,6 +289,8 @@ parameter_types! {
 
 /// Upper limit on the number of NPOS nominations.
 const MAX_QUOTA_NOMINATIONS: u32 = 16;
+/// Disabling factor set explicitly to byzantine threshold
+pub(crate) const SLASHING_DISABLING_FACTOR: usize = 3;
 
 impl pallet_staking::Config for Runtime {
 	type Currency = Balances;
@@ -308,7 +309,6 @@ impl pallet_staking::Config for Runtime {
 	type EraPayout = ();
 	type NextNewSession = Session;
 	type MaxExposurePageSize = ConstU32<256>;
-	type OffendingValidatorsThreshold = OffendingValidatorsThreshold;
 	type ElectionProvider = ElectionProviderMultiPhase;
 	type GenesisElectionProvider = onchain::OnChainExecution<OnChainSeqPhragmen>;
 	type VoterList = BagsList;
@@ -320,6 +320,7 @@ impl pallet_staking::Config for Runtime {
 	type EventListeners = Pools;
 	type WeightInfo = pallet_staking::weights::SubstrateWeight<Runtime>;
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy<SLASHING_DISABLING_FACTOR>;
 }
 
 impl<LocalCall> frame_system::offchain::SendTransactionTypes<LocalCall> for Runtime
@@ -871,7 +872,6 @@ pub(crate) fn on_offence_now(
 		offenders,
 		slash_fraction,
 		Staking::eras_start_session_index(now).unwrap(),
-		DisableStrategy::WhenSlashed,
 	);
 }
 
@@ -886,19 +886,16 @@ pub(crate) fn add_slash(who: &AccountId) {
 	);
 }
 
-// Slashes enough validators to cross the `Staking::OffendingValidatorsThreshold`.
-pub(crate) fn slash_through_offending_threshold() {
-	let validators = Session::validators();
-	let mut remaining_slashes =
-		<Runtime as pallet_staking::Config>::OffendingValidatorsThreshold::get() *
-			validators.len() as u32;
+// Slashes 1/2 of the active set. Returns the `AccountId`s of the slashed validators.
+pub(crate) fn slash_half_the_active_set() -> Vec<AccountId> {
+	let mut slashed = Session::validators();
+	slashed.truncate(slashed.len() / 2);
 
-	for v in validators.into_iter() {
-		if remaining_slashes != 0 {
-			add_slash(&v);
-			remaining_slashes -= 1;
-		}
+	for v in slashed.iter() {
+		add_slash(v);
 	}
+
+	slashed
 }
 
 // Slashes a percentage of the active nominators that haven't been slashed yet, with

substrate/frame/fast-unstake/src/mock.rs

@@ -134,7 +134,6 @@ impl pallet_staking::Config for Runtime {
 	type NextNewSession = ();
 	type HistoryDepth = ConstU32<84>;
 	type MaxExposurePageSize = ConstU32<64>;
-	type OffendingValidatorsThreshold = ();
 	type ElectionProvider = MockElection;
 	type GenesisElectionProvider = Self::ElectionProvider;
 	type VoterList = pallet_staking::UseNominatorsAndValidatorsMap<Self>;
@@ -145,6 +144,7 @@ impl pallet_staking::Config for Runtime {
 	type EventListeners = ();
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
 	type WeightInfo = ();
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 pub struct BalanceToU256;

substrate/frame/grandpa/src/mock.rs

@@ -146,7 +146,6 @@ parameter_types! {
 	pub const SessionsPerEra: SessionIndex = 3;
 	pub const BondingDuration: EraIndex = 3;
 	pub const RewardCurve: &'static PiecewiseLinear<'static> = &REWARD_CURVE;
-	pub const OffendingValidatorsThreshold: Perbill = Perbill::from_percent(17);
 	pub static ElectionsBoundsOnChain: ElectionBounds = ElectionBoundsBuilder::default().build();
 }
 
@@ -176,7 +175,6 @@ impl pallet_staking::Config for Test {
 	type UnixTime = pallet_timestamp::Pallet<Test>;
 	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type MaxExposurePageSize = ConstU32<64>;
-	type OffendingValidatorsThreshold = OffendingValidatorsThreshold;
 	type NextNewSession = Session;
 	type ElectionProvider = onchain::OnChainExecution<OnChainSeqPhragmen>;
 	type GenesisElectionProvider = Self::ElectionProvider;
@@ -189,6 +187,7 @@ impl pallet_staking::Config for Test {
 	type EventListeners = ();
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
 	type WeightInfo = ();
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 impl pallet_offences::Config for Test {

substrate/frame/im-online/src/lib.rs

@@ -104,7 +104,7 @@ use sp_runtime::{
 	PerThing, Perbill, Permill, RuntimeDebug, SaturatedConversion,
 };
 use sp_staking::{
-	offence::{DisableStrategy, Kind, Offence, ReportOffence},
+	offence::{Kind, Offence, ReportOffence},
 	SessionIndex,
 };
 use sp_std::prelude::*;
@@ -847,10 +847,6 @@ impl<Offender: Clone> Offence<Offender> for UnresponsivenessOffence<Offender> {
 		self.session_index
 	}
 
-	fn disable_strategy(&self) -> DisableStrategy {
-		DisableStrategy::Never
-	}
-
 	fn slash_fraction(&self, offenders: u32) -> Perbill {
 		// the formula is min((3 * (k - (n / 10 + 1))) / n, 1) * 0.07
 		// basically, 10% can be offline with no slash, but after that, it linearly climbs up to 7%

substrate/frame/im-online/src/tests.rs

@@ -50,9 +50,6 @@ fn test_unresponsiveness_slash_fraction() {
 		dummy_offence.slash_fraction(17),
 		Perbill::from_parts(46200000), // 4.62%
 	);
-
-	// Offline offences should never lead to being disabled.
-	assert_eq!(dummy_offence.disable_strategy(), DisableStrategy::Never);
 }
 
 #[test]

substrate/frame/nomination-pools/benchmarking/src/mock.rs

@@ -111,7 +111,6 @@ impl pallet_staking::Config for Runtime {
 	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = ();
 	type MaxExposurePageSize = ConstU32<64>;
-	type OffendingValidatorsThreshold = ();
 	type ElectionProvider =
 		frame_election_provider_support::NoElection<(AccountId, BlockNumber, Staking, ())>;
 	type GenesisElectionProvider = Self::ElectionProvider;
@@ -124,6 +123,7 @@ impl pallet_staking::Config for Runtime {
 	type EventListeners = Pools;
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
 	type WeightInfo = ();
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 parameter_types! {

substrate/frame/nomination-pools/test-staking/src/mock.rs

@@ -125,7 +125,6 @@ impl pallet_staking::Config for Runtime {
 	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = ();
 	type MaxExposurePageSize = ConstU32<64>;
-	type OffendingValidatorsThreshold = ();
 	type ElectionProvider =
 		frame_election_provider_support::NoElection<(AccountId, BlockNumber, Staking, ())>;
 	type GenesisElectionProvider = Self::ElectionProvider;
@@ -138,6 +137,7 @@ impl pallet_staking::Config for Runtime {
 	type EventListeners = Pools;
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
 	type WeightInfo = ();
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 parameter_types! {

substrate/frame/offences/benchmarking/src/mock.rs

@@ -174,7 +174,6 @@ impl pallet_staking::Config for Test {
 	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = Session;
 	type MaxExposurePageSize = ConstU32<64>;
-	type OffendingValidatorsThreshold = ();
 	type ElectionProvider = onchain::OnChainExecution<OnChainSeqPhragmen>;
 	type GenesisElectionProvider = Self::ElectionProvider;
 	type VoterList = pallet_staking::UseNominatorsAndValidatorsMap<Self>;
@@ -186,6 +185,7 @@ impl pallet_staking::Config for Test {
 	type EventListeners = ();
 	type BenchmarkingConfig = pallet_staking::TestBenchmarkingConfig;
 	type WeightInfo = ();
+	type DisablingStrategy = pallet_staking::UpToLimitDisablingStrategy;
 }
 
 impl pallet_im_online::Config for Test {