mm: validate device_hotplug is held for memory hotplug (3fc21924) · Commits · 戴 / test

mem_hotplug_begin() assumes that it can set mem_hotplug.active_writer and run the hotplug process without racing another thread. Validate this assumption with a lockdep assertion. Link: http://lkml.kernel.org/r/148693886229.16345.1770484669403334689.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by:

Dan Williams <dan.j.williams@intel.com> Reported-by:

Ben Hutchings <ben@decadent.org.uk> Cc: Michal Hocko <mhocko@suse.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/core.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -638,6 +638,11 @@ int lock_device_hotplug_sysfs(void)
		return restart_syscall();
		}

		void assert_held_device_hotplug(void)
		{
		lockdep_assert_held(&device_hotplug_lock);
		}

		#ifdef CONFIG_BLOCK
		static inline int device_is_not_partition(struct device *dev)
		{

include/linux/device.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1139,6 +1139,7 @@ static inline bool device_supports_offline(struct device *dev)
		extern void lock_device_hotplug(void);
		extern void unlock_device_hotplug(void);
		extern int lock_device_hotplug_sysfs(void);
		void assert_held_device_hotplug(void);
		extern int device_offline(struct device *dev);
		extern int device_online(struct device *dev);
		extern void set_primary_fwnode(struct device dev, struct fwnode_handle fwnode);

mm/memory_hotplug.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -126,6 +126,8 @@ void put_online_mems(void)

		void mem_hotplug_begin(void)
		{
		assert_held_device_hotplug();

		mem_hotplug.active_writer = current;

		memhp_lock_acquire();

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