lockdep: Fix per-cpu static objects (8ce371f9) · Commits · 戴 / test

Since commit ("locking/lockdep: Handle statically initialized PER_CPU locks properly") we try to collapse per-cpu locks into a single class by giving them all the same key. For this key we choose the canonical address of the per-cpu object, which would be the offset into the per-cpu area. This has two problems: - there is a case where we run !0 lock->key through static_obj() and expect this to pass; it doesn't for canonical pointers. - 0 is a valid canonical address. Cure both issues by redefining the canonical address as the address of the per-cpu variable on the boot CPU. Since I didn't want to rely on CPU0 being the boot-cpu, or even existing at all, track the boot CPU in a variable. Fixes: ("locking/lockdep: Handle statically initialized PER_CPU locks properly") Reported-by:

kernel test robot <fengguang.wu@intel.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by:

Borislav Petkov <bp@suse.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: linux-mm@kvack.org Cc: wfg@linux.intel.com Cc: kernel test robot <fengguang.wu@intel.com> Cc: LKP <lkp@01.org> Link: http://lkml.kernel.org/r/20170320114108.kbvcsuepem45j5cr@hirez.programming.kicks-ass.net Signed-off-by:

Thomas Gleixner <tglx@linutronix.de>

include/linux/smp.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -120,6 +120,13 @@ extern unsigned int setup_max_cpus;
		extern void __init setup_nr_cpu_ids(void);
		extern void __init smp_init(void);

		extern int __boot_cpu_id;

		static inline int get_boot_cpu_id(void)
		{
		return __boot_cpu_id;
		}

		#else /* !SMP */

		static inline void smp_send_stop(void) { }
		@@ -158,6 +165,11 @@ static inline void smp_init(void) { up_late_init(); }
		static inline void smp_init(void) { }
		#endif

		static inline int get_boot_cpu_id(void)
		{
		return 0;
		}

		#endif /* !SMP */

		/*

kernel/cpu.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1125,6 +1125,8 @@ core_initcall(cpu_hotplug_pm_sync_init);

		#endif /* CONFIG_PM_SLEEP_SMP */

		int __boot_cpu_id;

		#endif /* CONFIG_SMP */

		/* Boot processor state steps */
		@@ -1815,6 +1817,10 @@ void __init boot_cpu_init(void)
		set_cpu_active(cpu, true);
		set_cpu_present(cpu, true);
		set_cpu_possible(cpu, true);

		#ifdef CONFIG_SMP
		__boot_cpu_id = cpu;
		#endif
		}

		/*

kernel/module.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -682,8 +682,12 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
		void va = (void )addr;

		if (va >= start && va < start + mod->percpu_size) {
		if (can_addr)
		if (can_addr) {
		*can_addr = (unsigned long) (va - start);
		*can_addr += (unsigned long)
		per_cpu_ptr(mod->percpu,
		get_boot_cpu_id());
		}
		preempt_enable();
		return true;
		}

mm/percpu.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1293,8 +1293,11 @@ bool __is_kernel_percpu_address(unsigned long addr, unsigned long *can_addr)
		void va = (void )addr;

		if (va >= start && va < start + static_size) {
		if (can_addr)
		if (can_addr) {
		*can_addr = (unsigned long) (va - start);
		*can_addr += (unsigned long)
		per_cpu_ptr(base, get_boot_cpu_id());
		}
		return true;
		}
		}

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