From: David Hildenbrand <david@redhat.com>
To: stable@vger.kernel.org
Cc: linux-mm@kvack.org, Michal Hocko <mhocko@suse.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Baoquan He <bhe@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Oscar Salvador <osalvador@suse.de>,
Wei Yang <richard.weiyang@gmail.com>,
David Hildenbrand <david@redhat.com>
Subject: [PATCH for 4.19-stable v2 01/24] mm/memory_hotplug: make remove_memory() take the device_hotplug_lock
Date: Tue, 21 Jan 2020 19:01:27 +0100 [thread overview]
Message-ID: <20200121180150.37454-2-david@redhat.com> (raw)
In-Reply-To: <20200121180150.37454-1-david@redhat.com>
commit d15e59260f62bd5e0f625cf5f5240f6ffac78ab6 upstream.
Patch series "mm: online/offline_pages called w.o. mem_hotplug_lock", v3.
Reading through the code and studying how mem_hotplug_lock is to be used,
I noticed that there are two places where we can end up calling
device_online()/device_offline() - online_pages()/offline_pages() without
the mem_hotplug_lock. And there are other places where we call
device_online()/device_offline() without the device_hotplug_lock.
While e.g.
echo "online" > /sys/devices/system/memory/memory9/state
is fine, e.g.
echo 1 > /sys/devices/system/memory/memory9/online
Will not take the mem_hotplug_lock. However the device_lock() and
device_hotplug_lock.
E.g. via memory_probe_store(), we can end up calling
add_memory()->online_pages() without the device_hotplug_lock. So we can
have concurrent callers in online_pages(). We e.g. touch in
online_pages() basically unprotected zone->present_pages then.
Looks like there is a longer history to that (see Patch #2 for details),
and fixing it to work the way it was intended is not really possible. We
would e.g. have to take the mem_hotplug_lock in device/base/core.c, which
sounds wrong.
Summary: We had a lock inversion on mem_hotplug_lock and device_lock().
More details can be found in patch 3 and patch 6.
I propose the general rules (documentation added in patch 6):
1. add_memory/add_memory_resource() must only be called with
device_hotplug_lock.
2. remove_memory() must only be called with device_hotplug_lock. This is
already documented and holds for all callers.
3. device_online()/device_offline() must only be called with
device_hotplug_lock. This is already documented and true for now in core
code. Other callers (related to memory hotplug) have to be fixed up.
4. mem_hotplug_lock is taken inside of add_memory/remove_memory/
online_pages/offline_pages.
To me, this looks way cleaner than what we have right now (and easier to
verify). And looking at the documentation of remove_memory, using
lock_device_hotplug also for add_memory() feels natural.
This patch (of 6):
remove_memory() is exported right now but requires the
device_hotplug_lock, which is not exported. So let's provide a variant
that takes the lock and only export that one.
The lock is already held in
arch/powerpc/platforms/pseries/hotplug-memory.c
drivers/acpi/acpi_memhotplug.c
arch/powerpc/platforms/powernv/memtrace.c
Apart from that, there are not other users in the tree.
Link: http://lkml.kernel.org/r/20180925091457.28651-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/platforms/powernv/memtrace.c | 2 +-
arch/powerpc/platforms/pseries/hotplug-memory.c | 6 +++---
drivers/acpi/acpi_memhotplug.c | 2 +-
include/linux/memory_hotplug.h | 3 ++-
mm/memory_hotplug.c | 9 ++++++++-
5 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index dd3cc4632b9a..84d038ed3882 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -122,7 +122,7 @@ static u64 memtrace_alloc_node(u32 nid, u64 size)
*/
end_pfn = base_pfn + nr_pages;
for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) {
- remove_memory(nid, pfn << PAGE_SHIFT, bytes);
+ __remove_memory(nid, pfn << PAGE_SHIFT, bytes);
}
unlock_device_hotplug();
return base_pfn << PAGE_SHIFT;
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 7f86bc3eaade..ad46eabe9f5f 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -306,7 +306,7 @@ static int pseries_remove_memblock(unsigned long base, unsigned int memblock_siz
nid = memory_add_physaddr_to_nid(base);
for (i = 0; i < sections_per_block; i++) {
- remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
+ __remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
base += MIN_MEMORY_BLOCK_SIZE;
}
@@ -398,7 +398,7 @@ static int dlpar_remove_lmb(struct drmem_lmb *lmb)
block_sz = pseries_memory_block_size();
nid = memory_add_physaddr_to_nid(lmb->base_addr);
- remove_memory(nid, lmb->base_addr, block_sz);
+ __remove_memory(nid, lmb->base_addr, block_sz);
/* Update memory regions for memory remove */
memblock_remove(lmb->base_addr, block_sz);
@@ -685,7 +685,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
rc = dlpar_online_lmb(lmb);
if (rc) {
- remove_memory(nid, lmb->base_addr, block_sz);
+ __remove_memory(nid, lmb->base_addr, block_sz);
invalidate_lmb_associativity_index(lmb);
} else {
lmb->flags |= DRCONF_MEM_ASSIGNED;
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 2ccfbb61ca89..8fe0960ea572 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -282,7 +282,7 @@ static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
nid = memory_add_physaddr_to_nid(info->start_addr);
acpi_unbind_memory_blocks(info);
- remove_memory(nid, info->start_addr, info->length);
+ __remove_memory(nid, info->start_addr, info->length);
list_del(&info->list);
kfree(info);
}
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 4915e6cd7fd5..6f13a5a33b51 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -303,6 +303,7 @@ extern bool is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
extern void try_offline_node(int nid);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern void remove_memory(int nid, u64 start, u64 size);
+extern void __remove_memory(int nid, u64 start, u64 size);
#else
static inline bool is_mem_section_removable(unsigned long pfn,
@@ -319,6 +320,7 @@ static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
}
static inline void remove_memory(int nid, u64 start, u64 size) {}
+static inline void __remove_memory(int nid, u64 start, u64 size) {}
#endif /* CONFIG_MEMORY_HOTREMOVE */
extern void __ref free_area_init_core_hotplug(int nid);
@@ -333,7 +335,6 @@ extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages, struct vmem_altmap *altmap);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern bool is_memblock_offlined(struct memory_block *mem);
-extern void remove_memory(int nid, u64 start, u64 size);
extern int sparse_add_one_section(struct pglist_data *pgdat,
unsigned long start_pfn, struct vmem_altmap *altmap);
extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 413f6709039a..e2e2cf7014ee 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1893,7 +1893,7 @@ EXPORT_SYMBOL(try_offline_node);
* and online/offline operations before this call, as required by
* try_offline_node().
*/
-void __ref remove_memory(int nid, u64 start, u64 size)
+void __ref __remove_memory(int nid, u64 start, u64 size)
{
int ret;
@@ -1922,5 +1922,12 @@ void __ref remove_memory(int nid, u64 start, u64 size)
mem_hotplug_done();
}
+
+void remove_memory(int nid, u64 start, u64 size)
+{
+ lock_device_hotplug();
+ __remove_memory(nid, start, size);
+ unlock_device_hotplug();
+}
EXPORT_SYMBOL_GPL(remove_memory);
#endif /* CONFIG_MEMORY_HOTREMOVE */
--
2.24.1
next prev parent reply other threads:[~2020-01-21 18:02 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 18:01 [PATCH for 4.19-stable v2 00/24] mm/memory_hotplug: backport of pending stable fixes David Hildenbrand
2020-01-21 18:01 ` David Hildenbrand [this message]
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 02/24] mm, sparse: drop pgdat_resize_lock in sparse_add/remove_one_section() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 03/24] mm, sparse: pass nid instead of pgdat to sparse_add_one_section() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 04/24] drivers/base/memory.c: remove an unnecessary check on NR_MEM_SECTIONS David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 05/24] mm, memory_hotplug: add nid parameter to arch_remove_memory David Hildenbrand
2020-01-22 9:25 ` David Hildenbrand
2020-01-24 9:23 ` Greg Kroah-Hartman
2020-01-24 9:24 ` David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 06/24] mm/memory_hotplug: release memory resource after arch_remove_memory() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 07/24] drivers/base/memory.c: clean up relics in function parameters David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 08/24] mm, memory_hotplug: update a comment in unregister_memory() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 09/24] mm/memory_hotplug: make unregister_memory_section() never fail David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 10/24] mm/memory_hotplug: make __remove_section() " David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 11/24] powerpc/mm: Fix section mismatch warning David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 12/24] mm/memory_hotplug: make __remove_pages() and arch_remove_memory() never fail David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 13/24] s390x/mm: implement arch_remove_memory() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 14/24] mm/memory_hotplug: allow arch_remove_memory() without CONFIG_MEMORY_HOTREMOVE David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 15/24] drivers/base/memory: pass a block_id to init_memory_block() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 16/24] mm/memory_hotplug: create memory block devices after arch_add_memory() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 17/24] mm/memory_hotplug: remove memory block devices before arch_remove_memory() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 18/24] mm/memory_hotplug: make unregister_memory_block_under_nodes() never fail David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 19/24] mm/memory_hotplug: remove "zone" parameter from sparse_remove_one_section David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 20/24] mm/hotplug: kill is_dev_zone() usage in __remove_pages() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 21/24] drivers/base/node.c: simplify unregister_memory_block_under_nodes() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 22/24] mm/memunmap: don't access uninitialized memmap in memunmap_pages() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 23/24] mm/memory_hotplug: fix try_offline_node() David Hildenbrand
2020-01-21 18:01 ` [PATCH for 4.19-stable v2 24/24] mm/memory_hotplug: shrink zones when offlining memory David Hildenbrand
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