777c6e0dae
Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its
notifiers when HOTPLUG_CPU=y while the registration might succeed even
when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap
might keep a stale notifier on the list on the manual clean up during
the pool tear down and thus corrupt the list. Resulting in the following
[ 144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78
[ 144.971337] IP: [<ffffffffa290b00b>] raw_notifier_chain_register+0x1b/0x40
<snipped>
[ 145.122628] Call Trace:
[ 145.125086] [<ffffffffa28e5cf8>] __register_cpu_notifier+0x18/0x20
[ 145.131350] [<ffffffffa2a5dd73>] zswap_pool_create+0x273/0x400
[ 145.137268] [<ffffffffa2a5e0fc>] __zswap_param_set+0x1fc/0x300
[ 145.143188] [<ffffffffa2944c1d>] ? trace_hardirqs_on+0xd/0x10
[ 145.149018] [<ffffffffa2908798>] ? kernel_param_lock+0x28/0x30
[ 145.154940] [<ffffffffa2a3e8cf>] ? __might_fault+0x4f/0xa0
[ 145.160511] [<ffffffffa2a5e237>] zswap_compressor_param_set+0x17/0x20
[ 145.167035] [<ffffffffa2908d3c>] param_attr_store+0x5c/0xb0
[ 145.172694] [<ffffffffa290848d>] module_attr_store+0x1d/0x30
[ 145.178443] [<ffffffffa2b2b41f>] sysfs_kf_write+0x4f/0x70
[ 145.183925] [<ffffffffa2b2a5b9>] kernfs_fop_write+0x149/0x180
[ 145.189761] [<ffffffffa2a99248>] __vfs_write+0x18/0x40
[ 145.194982] [<ffffffffa2a9a412>] vfs_write+0xb2/0x1a0
[ 145.200122] [<ffffffffa2a9a732>] SyS_write+0x52/0xa0
[ 145.205177] [<ffffffffa2ff4d97>] entry_SYSCALL_64_fastpath+0x12/0x17
This can be even triggered manually by changing
/sys/module/zswap/parameters/compressor multiple times.
Fix this issue by making unregister APIs symmetric to the register so
there are no surprises.
Fixes: 47e627bc8c ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU")
Reported-and-tested-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
249 lines
7.6 KiB
C
249 lines
7.6 KiB
C
/*
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* include/linux/cpu.h - generic cpu definition
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*
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* This is mainly for topological representation. We define the
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* basic 'struct cpu' here, which can be embedded in per-arch
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* definitions of processors.
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*
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* Basic handling of the devices is done in drivers/base/cpu.c
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*
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* CPUs are exported via sysfs in the devices/system/cpu
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* directory.
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*/
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#ifndef _LINUX_CPU_H_
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#define _LINUX_CPU_H_
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#include <linux/node.h>
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#include <linux/compiler.h>
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#include <linux/cpumask.h>
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#include <linux/cpuhotplug.h>
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struct device;
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struct device_node;
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struct attribute_group;
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struct cpu {
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int node_id; /* The node which contains the CPU */
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int hotpluggable; /* creates sysfs control file if hotpluggable */
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struct device dev;
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};
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extern void boot_cpu_init(void);
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extern void boot_cpu_state_init(void);
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extern int register_cpu(struct cpu *cpu, int num);
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extern struct device *get_cpu_device(unsigned cpu);
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extern bool cpu_is_hotpluggable(unsigned cpu);
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extern bool arch_match_cpu_phys_id(int cpu, u64 phys_id);
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extern bool arch_find_n_match_cpu_physical_id(struct device_node *cpun,
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int cpu, unsigned int *thread);
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extern int cpu_add_dev_attr(struct device_attribute *attr);
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extern void cpu_remove_dev_attr(struct device_attribute *attr);
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extern int cpu_add_dev_attr_group(struct attribute_group *attrs);
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extern void cpu_remove_dev_attr_group(struct attribute_group *attrs);
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extern __printf(4, 5)
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struct device *cpu_device_create(struct device *parent, void *drvdata,
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const struct attribute_group **groups,
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const char *fmt, ...);
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#ifdef CONFIG_HOTPLUG_CPU
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extern void unregister_cpu(struct cpu *cpu);
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extern ssize_t arch_cpu_probe(const char *, size_t);
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extern ssize_t arch_cpu_release(const char *, size_t);
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#endif
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struct notifier_block;
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#define CPU_ONLINE 0x0002 /* CPU (unsigned)v is up */
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#define CPU_UP_PREPARE 0x0003 /* CPU (unsigned)v coming up */
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#define CPU_UP_CANCELED 0x0004 /* CPU (unsigned)v NOT coming up */
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#define CPU_DOWN_PREPARE 0x0005 /* CPU (unsigned)v going down */
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#define CPU_DOWN_FAILED 0x0006 /* CPU (unsigned)v NOT going down */
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#define CPU_DEAD 0x0007 /* CPU (unsigned)v dead */
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#define CPU_POST_DEAD 0x0009 /* CPU (unsigned)v dead, cpu_hotplug
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* lock is dropped */
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#define CPU_BROKEN 0x000B /* CPU (unsigned)v did not die properly,
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* perhaps due to preemption. */
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/* Used for CPU hotplug events occurring while tasks are frozen due to a suspend
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* operation in progress
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*/
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#define CPU_TASKS_FROZEN 0x0010
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#define CPU_ONLINE_FROZEN (CPU_ONLINE | CPU_TASKS_FROZEN)
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#define CPU_UP_PREPARE_FROZEN (CPU_UP_PREPARE | CPU_TASKS_FROZEN)
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#define CPU_UP_CANCELED_FROZEN (CPU_UP_CANCELED | CPU_TASKS_FROZEN)
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#define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN)
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#define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
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#define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN)
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#ifdef CONFIG_SMP
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extern bool cpuhp_tasks_frozen;
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/* Need to know about CPUs going up/down? */
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#if defined(CONFIG_HOTPLUG_CPU) || !defined(MODULE)
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#define cpu_notifier(fn, pri) { \
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static struct notifier_block fn##_nb = \
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{ .notifier_call = fn, .priority = pri }; \
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register_cpu_notifier(&fn##_nb); \
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}
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#define __cpu_notifier(fn, pri) { \
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static struct notifier_block fn##_nb = \
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{ .notifier_call = fn, .priority = pri }; \
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__register_cpu_notifier(&fn##_nb); \
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}
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extern int register_cpu_notifier(struct notifier_block *nb);
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extern int __register_cpu_notifier(struct notifier_block *nb);
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extern void unregister_cpu_notifier(struct notifier_block *nb);
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extern void __unregister_cpu_notifier(struct notifier_block *nb);
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#else /* #if defined(CONFIG_HOTPLUG_CPU) || !defined(MODULE) */
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#define cpu_notifier(fn, pri) do { (void)(fn); } while (0)
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#define __cpu_notifier(fn, pri) do { (void)(fn); } while (0)
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static inline int register_cpu_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline int __register_cpu_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline void unregister_cpu_notifier(struct notifier_block *nb)
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{
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}
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static inline void __unregister_cpu_notifier(struct notifier_block *nb)
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{
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}
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#endif
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int cpu_up(unsigned int cpu);
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void notify_cpu_starting(unsigned int cpu);
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extern void cpu_maps_update_begin(void);
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extern void cpu_maps_update_done(void);
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#define cpu_notifier_register_begin cpu_maps_update_begin
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#define cpu_notifier_register_done cpu_maps_update_done
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#else /* CONFIG_SMP */
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#define cpuhp_tasks_frozen 0
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#define cpu_notifier(fn, pri) do { (void)(fn); } while (0)
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#define __cpu_notifier(fn, pri) do { (void)(fn); } while (0)
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static inline int register_cpu_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline int __register_cpu_notifier(struct notifier_block *nb)
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{
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return 0;
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}
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static inline void unregister_cpu_notifier(struct notifier_block *nb)
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{
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}
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static inline void __unregister_cpu_notifier(struct notifier_block *nb)
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{
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}
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static inline void cpu_maps_update_begin(void)
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{
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}
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static inline void cpu_maps_update_done(void)
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{
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}
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static inline void cpu_notifier_register_begin(void)
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{
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}
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static inline void cpu_notifier_register_done(void)
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{
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}
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#endif /* CONFIG_SMP */
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extern struct bus_type cpu_subsys;
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#ifdef CONFIG_HOTPLUG_CPU
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/* Stop CPUs going up and down. */
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extern void cpu_hotplug_begin(void);
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extern void cpu_hotplug_done(void);
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extern void get_online_cpus(void);
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extern void put_online_cpus(void);
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extern void cpu_hotplug_disable(void);
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extern void cpu_hotplug_enable(void);
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#define hotcpu_notifier(fn, pri) cpu_notifier(fn, pri)
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#define __hotcpu_notifier(fn, pri) __cpu_notifier(fn, pri)
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#define register_hotcpu_notifier(nb) register_cpu_notifier(nb)
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#define __register_hotcpu_notifier(nb) __register_cpu_notifier(nb)
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#define unregister_hotcpu_notifier(nb) unregister_cpu_notifier(nb)
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#define __unregister_hotcpu_notifier(nb) __unregister_cpu_notifier(nb)
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void clear_tasks_mm_cpumask(int cpu);
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int cpu_down(unsigned int cpu);
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#else /* CONFIG_HOTPLUG_CPU */
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static inline void cpu_hotplug_begin(void) {}
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static inline void cpu_hotplug_done(void) {}
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#define get_online_cpus() do { } while (0)
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#define put_online_cpus() do { } while (0)
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#define cpu_hotplug_disable() do { } while (0)
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#define cpu_hotplug_enable() do { } while (0)
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#define hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
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#define __hotcpu_notifier(fn, pri) do { (void)(fn); } while (0)
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/* These aren't inline functions due to a GCC bug. */
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#define register_hotcpu_notifier(nb) ({ (void)(nb); 0; })
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#define __register_hotcpu_notifier(nb) ({ (void)(nb); 0; })
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#define unregister_hotcpu_notifier(nb) ({ (void)(nb); })
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#define __unregister_hotcpu_notifier(nb) ({ (void)(nb); })
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#endif /* CONFIG_HOTPLUG_CPU */
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#ifdef CONFIG_PM_SLEEP_SMP
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extern int freeze_secondary_cpus(int primary);
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static inline int disable_nonboot_cpus(void)
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{
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return freeze_secondary_cpus(0);
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}
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extern void enable_nonboot_cpus(void);
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#else /* !CONFIG_PM_SLEEP_SMP */
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static inline int disable_nonboot_cpus(void) { return 0; }
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static inline void enable_nonboot_cpus(void) {}
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#endif /* !CONFIG_PM_SLEEP_SMP */
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void cpu_startup_entry(enum cpuhp_state state);
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void cpu_idle_poll_ctrl(bool enable);
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/* Attach to any functions which should be considered cpuidle. */
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#define __cpuidle __attribute__((__section__(".cpuidle.text")))
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bool cpu_in_idle(unsigned long pc);
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void arch_cpu_idle(void);
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void arch_cpu_idle_prepare(void);
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void arch_cpu_idle_enter(void);
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void arch_cpu_idle_exit(void);
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void arch_cpu_idle_dead(void);
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int cpu_report_state(int cpu);
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int cpu_check_up_prepare(int cpu);
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void cpu_set_state_online(int cpu);
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#ifdef CONFIG_HOTPLUG_CPU
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bool cpu_wait_death(unsigned int cpu, int seconds);
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bool cpu_report_death(void);
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void cpuhp_report_idle_dead(void);
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#else
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static inline void cpuhp_report_idle_dead(void) { }
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#endif /* #ifdef CONFIG_HOTPLUG_CPU */
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#endif /* _LINUX_CPU_H_ */
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