The patch titled
Subject: mm: validate device_hotplug is held for memory hotplug
has been added to the -mm tree. Its filename is
mm-validate-device_hotplug-is-held-for-memory-hotplug.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-validate-device_hotplug-is-held-for-memory-hotplug.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-validate-device_hotplug-is-held-for-memory-hotplug.patch
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------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm: validate device_hotplug is held for memory hotplug
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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/core.c | 5 +++++
include/linux/device.h | 1 +
mm/memory_hotplug.c | 2 ++
3 files changed, 8 insertions(+)
diff -puN drivers/base/core.c~mm-validate-device_hotplug-is-held-for-memory-hotplug drivers/base/core.c
--- a/drivers/base/core.c~mm-validate-device_hotplug-is-held-for-memory-hotplug
+++ a/drivers/base/core.c
@@ -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)
{
diff -puN include/linux/device.h~mm-validate-device_hotplug-is-held-for-memory-hotplug include/linux/device.h
--- a/include/linux/device.h~mm-validate-device_hotplug-is-held-for-memory-hotplug
+++ a/include/linux/device.h
@@ -1135,6 +1135,7 @@ static inline bool device_supports_offli
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);
diff -puN mm/memory_hotplug.c~mm-validate-device_hotplug-is-held-for-memory-hotplug mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-validate-device_hotplug-is-held-for-memory-hotplug
+++ a/mm/memory_hotplug.c
@@ -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();
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
mm-fix-type-width-of-section-to-from-pfn-conversion-macros.patch
mm-devm_memremap_pages-use-multi-order-radix-for-zone_device-lookups.patch
mm-introduce-struct-mem_section_usage-to-track-partial-population-of-a-section.patch
mm-introduce-common-definitions-for-the-size-and-mask-of-a-section.patch
mm-cleanup-sparse_init_one_section-return-value.patch
mm-track-active-portions-of-a-section-at-boot.patch
mm-fix-register_new_memory-zone-type-detection.patch
mm-convert-kmalloc_section_memmap-to-populate_section_memmap.patch
mm-prepare-for-hot-add-remove-of-sub-section-ranges.patch
mm-support-section-unaligned-zone_device-memory-ranges.patch
mm-support-section-unaligned-zone_device-memory-ranges-fix-2.patch
mm-enable-section-unaligned-devm_memremap_pages.patch
libnvdimm-pfn-dax-stop-padding-pmem-namespaces-to-section-alignment.patch
mm-fix-get_user_pages-vs-device-dax-pud-mappings.patch
mm-devm_memremap_pages-hold-device_hotplug-lock-over-mem_hotplug_begin-done.patch
mm-validate-device_hotplug-is-held-for-memory-hotplug.patch
--
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