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android / kernel / common / refs/heads/export-to-partner-android-3adeb2ab1ae3e5820d1acd11e3f4ad8d9b0ec102^! / .
commit3adeb2ab1ae3e5820d1acd11e3f4ad8d9b0ec102[log] [tgz]
authorJason Chiu <[email protected]>Thu Sep 30 14:20:14 2021 +0800
committerJonglin Lee <[email protected]>Thu Sep 30 15:26:34 2021 -0700
treecb474164ca6ab1f44548da7fd4eccd03c22f215a
parente743b07f1d42586dc2afe833cf63ea9e54906477 [diff]
Revert "sched/core: Initialize the idle task with preemption disabled"

This reverts commit 3c51d82d0b7862d7d246016c74b4390fb1fa1f11.

This commit introduce b/201047587, and easily reproduce via CPU
hotplug test.

Bug: 201047587
Signed-off-by: Jason Chiu <[email protected]>
Change-Id: Iade76908c410291718c9cd81716c2473381072fa

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index cb64e47..f3a58c1 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c

@@ -166,6 +166,7 @@ smp_callin(void)
 	DBGS(("smp_callin: commencing CPU %d current %p active_mm %p\n",
 	      cpuid, current, current->active_mm));
 
+	preempt_disable();
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }
 

diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index db0e104..52906d3 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c

@@ -189,6 +189,7 @@ void start_kernel_secondary(void)
 	pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
 
 	local_irq_enable();
+	preempt_disable();
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }
 

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 123432b..ba27e18 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c

@@ -436,6 +436,7 @@ asmlinkage void secondary_start_kernel(void)
 #endif
 	pr_debug("CPU%u: Booted secondary processor\n", cpu);
 
+	preempt_disable();
 	trace_hardirqs_off();
 
 	/*

diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
index e83f098..80e946b 100644
--- a/arch/arm64/include/asm/preempt.h
+++ b/arch/arm64/include/asm/preempt.h

@@ -23,7 +23,7 @@ static inline void preempt_count_set(u64 pc)
 } while (0)
 
 #define init_idle_preempt_count(p, cpu) do { \
-	task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
+	task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
 } while (0)
 
 static inline void set_preempt_need_resched(void)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 92a1bbb..1bcf403 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c

@@ -232,6 +232,7 @@ asmlinkage notrace void secondary_start_kernel(void)
 		init_gic_priority_masking();
 
 	rcu_cpu_starting(cpu);
+	preempt_disable();
 	trace_hardirqs_off();
 
 	/*

diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 1a8d7ea..041d0de 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c

@@ -282,6 +282,7 @@ void csky_start_secondary(void)
 	pr_info("CPU%u Online: %s...\n", cpu, __func__);
 
 	local_irq_enable();
+	preempt_disable();
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }
 

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 0cad990..093040f 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c

@@ -440,6 +440,7 @@ start_secondary (void *unused)
 #endif
 	efi_map_pal_code();
 	cpu_init();
+	preempt_disable();
 	smp_callin();
 
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index ff25926..48d84d5 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c

@@ -348,6 +348,7 @@ asmlinkage void start_secondary(void)
 	 */
 
 	calibrate_delay();
+	preempt_disable();
 	cpu = smp_processor_id();
 	cpu_data[cpu].udelay_val = loops_per_jiffy;
 

diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index e4dad76..29c82ef 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c

@@ -134,6 +134,8 @@ asmlinkage __init void secondary_start_kernel(void)
 	set_cpu_online(cpu, true);
 
 	local_irq_enable();
+
+	preempt_disable();
 	/*
 	 * OK, it's off to the idle thread for us
 	 */

diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 1405b603..10227f6 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c

@@ -302,6 +302,7 @@ void __init smp_callin(unsigned long pdce_proc)
 #endif
 
 	smp_cpu_init(slave_id);
+	preempt_disable();
 
 	flush_cache_all_local(); /* start with known state */
 	flush_tlb_all_local(NULL);

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 91f2741..aa0a35e 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c

@@ -1436,6 +1436,7 @@ void start_secondary(void *unused)
 	smp_store_cpu_info(cpu);
 	set_dec(tb_ticks_per_jiffy);
 	rcu_cpu_starting(cpu);
+	preempt_disable();
 	cpu_callin_map[cpu] = 1;
 
 	if (smp_ops->setup_cpu)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 0b04e0e..96167d5 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c

@@ -166,6 +166,7 @@ asmlinkage __visible void smp_callin(void)
 	 * Disable preemption before enabling interrupts, so we don't try to
 	 * schedule a CPU that hasn't actually started yet.
 	 */
+	preempt_disable();
 	local_irq_enable();
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }

diff --git a/arch/s390/include/asm/preempt.h b/arch/s390/include/asm/preempt.h
index e38480e..6ede299 100644
--- a/arch/s390/include/asm/preempt.h
+++ b/arch/s390/include/asm/preempt.h

@@ -32,7 +32,7 @@ static inline void preempt_count_set(int pc)
 #define init_task_preempt_count(p)	do { } while (0)
 
 #define init_idle_preempt_count(p, cpu)	do { \
-	S390_lowcore.preempt_count = PREEMPT_DISABLED; \
+	S390_lowcore.preempt_count = PREEMPT_ENABLED; \
 } while (0)
 
 static inline void set_preempt_need_resched(void)
@@ -91,7 +91,7 @@ static inline void preempt_count_set(int pc)
 #define init_task_preempt_count(p)	do { } while (0)
 
 #define init_idle_preempt_count(p, cpu)	do { \
-	S390_lowcore.preempt_count = PREEMPT_DISABLED; \
+	S390_lowcore.preempt_count = PREEMPT_ENABLED; \
 } while (0)
 
 static inline void set_preempt_need_resched(void)

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 7db5460..791bc37 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c

@@ -863,6 +863,7 @@ static void smp_init_secondary(void)
 	set_cpu_flag(CIF_ASCE_SECONDARY);
 	cpu_init();
 	rcu_cpu_starting(cpu);
+	preempt_disable();
 	init_cpu_timer();
 	vtime_init();
 	pfault_init();

diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 65924d9e..372acdc 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c

@@ -186,6 +186,8 @@ asmlinkage void start_secondary(void)
 
 	per_cpu_trap_init();
 
+	preempt_disable();
+
 	notify_cpu_starting(cpu);
 
 	local_irq_enable();

diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index 22b148e..50c127a 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c

@@ -348,6 +348,7 @@ static void sparc_start_secondary(void *arg)
 	 */
 	arch_cpu_pre_starting(arg);
 
+	preempt_disable();
 	cpu = smp_processor_id();
 
 	notify_cpu_starting(cpu);

diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index ae5faa1..e38d8bf 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c

@@ -138,6 +138,9 @@ void smp_callin(void)
 
 	set_cpu_online(cpuid, true);
 
+	/* idle thread is expected to have preempt disabled */
+	preempt_disable();
+
 	local_irq_enable();
 
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index a334dd0..69485ca 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h

@@ -43,7 +43,7 @@ static __always_inline void preempt_count_set(int pc)
 #define init_task_preempt_count(p) do { } while (0)
 
 #define init_idle_preempt_count(p, cpu) do { \
-	per_cpu(__preempt_count, (cpu)) = PREEMPT_DISABLED; \
+	per_cpu(__preempt_count, (cpu)) = PREEMPT_ENABLED; \
 } while (0)
 
 /*

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 8baff50..582387f 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c

@@ -230,6 +230,7 @@ static void notrace start_secondary(void *unused)
 	cpu_init_exception_handling();
 	cpu_init();
 	x86_cpuinit.early_percpu_clock_init();
+	preempt_disable();
 	smp_callin();
 
 	enable_start_cpu0 = 0;

diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index 1254da07..cd85a7a 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c

@@ -145,6 +145,7 @@ void secondary_start_kernel(void)
 	cpumask_set_cpu(cpu, mm_cpumask(mm));
 	enter_lazy_tlb(mm, current);
 
+	preempt_disable();
 	trace_hardirqs_off();
 
 	calibrate_delay();

diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index b4d43a4..d683f5e 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h

@@ -29,7 +29,7 @@ static __always_inline void preempt_count_set(int pc)
 } while (0)
 
 #define init_idle_preempt_count(p, cpu) do { \
-	task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
+	task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
 } while (0)
 
 static __always_inline void set_preempt_need_resched(void)

diff --git a/init/main.c b/init/main.c
index c5f7de7..9934624 100644
--- a/init/main.c
+++ b/init/main.c

@@ -908,7 +908,11 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 	 * time - but meanwhile we still have a functioning scheduler.
 	 */
 	sched_init();
-
+	/*
+	 * Disable preemption - early bootup scheduling is extremely
+	 * fragile until we cpu_idle() for the first time.
+	 */
+	preempt_disable();
 	if (WARN(!irqs_disabled(),
 		 "Interrupts were enabled *very* early, fixing it\n"))
 		local_irq_disable();

diff --git a/kernel/fork.c b/kernel/fork.c
index 16018dc..ec8c47c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c

@@ -2434,7 +2434,7 @@ static inline void init_idle_pids(struct task_struct *idle)
 	}
 }
 
-struct task_struct * __init fork_idle(int cpu)
+struct task_struct *fork_idle(int cpu)
 {
 	struct task_struct *task;
 	struct kernel_clone_args args = {

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 34a69dd..891f85b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c

@@ -6743,7 +6743,7 @@ void show_state_filter(unsigned long state_filter)
  * NOTE: this function does not set the idle thread's NEED_RESCHED
  * flag, to make booting more robust.
  */
-void __init init_idle(struct task_struct *idle, int cpu)
+void init_idle(struct task_struct *idle, int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 	unsigned long flags;

diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index e416304..f25208e8 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c

@@ -33,6 +33,7 @@ struct task_struct *idle_thread_get(unsigned int cpu)
 
 	if (!tsk)
 		return ERR_PTR(-ENOMEM);
+	init_idle(tsk, cpu);
 	return tsk;
 }