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Message-Id: <20191127203105.183245523@linuxfoundation.org>
Date: Wed, 27 Nov 2019 21:30:51 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, David Hildenbrand <david@...hat.com>,
Pavel Tatashin <pavel.tatashin@...rosoft.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Rashmica Gupta <rashmica.g@...il.com>,
Oscar Salvador <osalvador@...e.de>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>,
Nathan Fontenot <nfont@...ux.vnet.ibm.com>,
John Allen <jallen@...ux.vnet.ibm.com>,
Michal Hocko <mhocko@...e.com>,
Dan Williams <dan.j.williams@...el.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Vlastimil Babka <vbabka@...e.cz>,
Mathieu Malaterre <malat@...ian.org>,
YASUAKI ISHIMATSU <yasu.isimatu@...il.com>,
Balbir Singh <bsingharora@...il.com>,
Haiyang Zhang <haiyangz@...rosoft.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Jonathan Corbet <corbet@....net>,
Kate Stewart <kstewart@...uxfoundation.org>,
"K. Y. Srinivasan" <kys@...rosoft.com>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Michael Neuling <mikey@...ling.org>,
Philippe Ombredanne <pombredanne@...b.com>,
Stephen Hemminger <sthemmin@...rosoft.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 118/211] mm/memory_hotplug: make add_memory() take the device_hotplug_lock
From: David Hildenbrand <david@...hat.com>
[ Upstream commit 8df1d0e4a265f25dc1e7e7624ccdbcb4a6630c89 ]
add_memory() currently does not take the device_hotplug_lock, however
is aleady called under the lock from
arch/powerpc/platforms/pseries/hotplug-memory.c
drivers/acpi/acpi_memhotplug.c
to synchronize against CPU hot-remove and similar.
In general, we should hold the device_hotplug_lock when adding memory to
synchronize against online/offline request (e.g. from user space) - which
already resulted in lock inversions due to device_lock() and
mem_hotplug_lock - see 30467e0b3be ("mm, hotplug: fix concurrent memory
hot-add deadlock"). add_memory()/add_memory_resource() will create memory
block devices, so this really feels like the right thing to do.
Holding the device_hotplug_lock makes sure that a memory block device
can really only be accessed (e.g. via .online/.state) from user space,
once the memory has been fully added to the system.
The lock is not held yet in
drivers/xen/balloon.c
arch/powerpc/platforms/powernv/memtrace.c
drivers/s390/char/sclp_cmd.c
drivers/hv/hv_balloon.c
So, let's either use the locked variants or take the lock.
Don't export add_memory_resource(), as it once was exported to be used by
XEN, which is never built as a module. If somebody requires it, we also
have to export a locked variant (as device_hotplug_lock is never
exported).
Link: http://lkml.kernel.org/r/20180925091457.28651-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@...hat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@...rosoft.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Reviewed-by: Rashmica Gupta <rashmica.g@...il.com>
Reviewed-by: Oscar Salvador <osalvador@...e.de>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: Len Brown <lenb@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Nathan Fontenot <nfont@...ux.vnet.ibm.com>
Cc: John Allen <jallen@...ux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Vlastimil Babka <vbabka@...e.cz>
Cc: Mathieu Malaterre <malat@...ian.org>
Cc: Pavel Tatashin <pavel.tatashin@...rosoft.com>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@...il.com>
Cc: Balbir Singh <bsingharora@...il.com>
Cc: Haiyang Zhang <haiyangz@...rosoft.com>
Cc: Heiko Carstens <heiko.carstens@...ibm.com>
Cc: Jonathan Corbet <corbet@....net>
Cc: Kate Stewart <kstewart@...uxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@...rosoft.com>
Cc: Martin Schwidefsky <schwidefsky@...ibm.com>
Cc: Michael Neuling <mikey@...ling.org>
Cc: Philippe Ombredanne <pombredanne@...b.com>
Cc: Stephen Hemminger <sthemmin@...rosoft.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
.../platforms/pseries/hotplug-memory.c | 2 +-
drivers/acpi/acpi_memhotplug.c | 2 +-
drivers/base/memory.c | 9 ++++++--
drivers/xen/balloon.c | 3 +++
include/linux/memory_hotplug.h | 1 +
mm/memory_hotplug.c | 22 ++++++++++++++++---
6 files changed, 32 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 93e09f108ca17..99a3cf51c5ba4 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -787,7 +787,7 @@ static int dlpar_add_lmb(struct of_drconf_cell *lmb)
nid = memory_add_physaddr_to_nid(lmb->base_addr);
/* Add the memory */
- rc = add_memory(nid, lmb->base_addr, block_sz);
+ rc = __add_memory(nid, lmb->base_addr, block_sz);
if (rc) {
dlpar_remove_device_tree_lmb(lmb);
return rc;
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 6b0d3ef7309cb..2ccfbb61ca899 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -228,7 +228,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
if (node < 0)
node = memory_add_physaddr_to_nid(info->start_addr);
- result = add_memory(node, info->start_addr, info->length);
+ result = __add_memory(node, info->start_addr, info->length);
/*
* If the memory block has been used by the kernel, add_memory()
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index c617e00f4361d..8e5818e735e2f 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -517,15 +517,20 @@ memory_probe_store(struct device *dev, struct device_attribute *attr,
if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
return -EINVAL;
+ ret = lock_device_hotplug_sysfs();
+ if (ret)
+ goto out;
+
nid = memory_add_physaddr_to_nid(phys_addr);
- ret = add_memory(nid, phys_addr,
- MIN_MEMORY_BLOCK_SIZE * sections_per_block);
+ ret = __add_memory(nid, phys_addr,
+ MIN_MEMORY_BLOCK_SIZE * sections_per_block);
if (ret)
goto out;
ret = count;
out:
+ unlock_device_hotplug();
return ret;
}
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 7d521babc020b..71a6deeb4e714 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -356,7 +356,10 @@ static enum bp_state reserve_additional_memory(void)
* callers drop the mutex before trying again.
*/
mutex_unlock(&balloon_mutex);
+ /* add_memory_resource() requires the device_hotplug lock */
+ lock_device_hotplug();
rc = add_memory_resource(nid, resource, memhp_auto_online);
+ unlock_device_hotplug();
mutex_lock(&balloon_mutex);
if (rc) {
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 58e110aee7ab4..d36a029353915 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -316,6 +316,7 @@ static inline void remove_memory(int nid, u64 start, u64 size) {}
extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
void *arg, int (*func)(struct memory_block *, void *));
+extern int __add_memory(int nid, u64 start, u64 size);
extern int add_memory(int nid, u64 start, u64 size);
extern int add_memory_resource(int nid, struct resource *resource, bool online);
extern int arch_add_memory(int nid, u64 start, u64 size, bool want_memblock);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d4affa9982cac..e368a4e0c7cbc 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1073,7 +1073,12 @@ static int online_memory_block(struct memory_block *mem, void *arg)
return device_online(&mem->dev);
}
-/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+/*
+ * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
+ * and online/offline operations (triggered e.g. by sysfs).
+ *
+ * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
+ */
int __ref add_memory_resource(int nid, struct resource *res, bool online)
{
u64 start, size;
@@ -1166,9 +1171,9 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
mem_hotplug_done();
return ret;
}
-EXPORT_SYMBOL_GPL(add_memory_resource);
-int __ref add_memory(int nid, u64 start, u64 size)
+/* requires device_hotplug_lock, see add_memory_resource() */
+int __ref __add_memory(int nid, u64 start, u64 size)
{
struct resource *res;
int ret;
@@ -1182,6 +1187,17 @@ int __ref add_memory(int nid, u64 start, u64 size)
release_memory_resource(res);
return ret;
}
+
+int add_memory(int nid, u64 start, u64 size)
+{
+ int rc;
+
+ lock_device_hotplug();
+ rc = __add_memory(nid, start, size);
+ unlock_device_hotplug();
+
+ return rc;
+}
EXPORT_SYMBOL_GPL(add_memory);
#ifdef CONFIG_MEMORY_HOTREMOVE
--
2.20.1
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