[PATCH v1] drivers/base/memory: add memory block to memory group after registration succeeded
If register_memory() fails, we freed the memory block but already added the memory block to the group list, not good. Let's defer adding the block to the memory group to after registering the memory block device.
We do handle it properly during unregister_memory(), but that's not called when the registration fails.
Fixes: 028fc57a1c36 ("drivers/base/memory: introduce "memory groups" to logically group memory blocks") Cc: stable@vger.kernel.org # v5.15+ Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: "Rafael J. Wysocki" rafael@kernel.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: Oscar Salvador osalvador@suse.de Signed-off-by: David Hildenbrand david@redhat.com --- drivers/base/memory.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 365cd4a7f239..60c38f9cf1a7 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -663,14 +663,16 @@ static int init_memory_block(unsigned long block_id, unsigned long state, mem->nr_vmemmap_pages = nr_vmemmap_pages; INIT_LIST_HEAD(&mem->group_next);
+ ret = register_memory(mem); + if (ret) + return ret; + if (group) { mem->group = group; list_add(&mem->group_next, &group->memory_blocks); }
- ret = register_memory(mem); - - return ret; + return 0; }
static int add_memory_block(unsigned long base_section_nr)
On Fri, Jan 28, 2022 at 03:45:40PM +0100, David Hildenbrand wrote:
If register_memory() fails, we freed the memory block but already added the memory block to the group list, not good. Let's defer adding the block to the memory group to after registering the memory block device.
We do handle it properly during unregister_memory(), but that's not called when the registration fails.
Fixes: 028fc57a1c36 ("drivers/base/memory: introduce "memory groups" to logically group memory blocks") Cc: stable@vger.kernel.org # v5.15+ Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: "Rafael J. Wysocki" rafael@kernel.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: Oscar Salvador osalvador@suse.de Signed-off-by: David Hildenbrand david@redhat.com
Reviewed-by: Oscar Salvador osalvador@suse.de
On Fri, 28 Jan 2022 15:45:40 +0100 David Hildenbrand david@redhat.com wrote:
If register_memory() fails, we freed the memory block but already added the memory block to the group list, not good. Let's defer adding the block to the memory group to after registering the memory block device.
We do handle it properly during unregister_memory(), but that's not called when the registration fails.
I guess this has never been known to happen. So I queued the fix for 5.18-rc1, cc:stable.
On 01.02.22 02:01, Andrew Morton wrote:
On Fri, 28 Jan 2022 15:45:40 +0100 David Hildenbrand david@redhat.com wrote:
If register_memory() fails, we freed the memory block but already added the memory block to the group list, not good. Let's defer adding the block to the memory group to after registering the memory block device.
We do handle it properly during unregister_memory(), but that's not called when the registration fails.
I guess this has never been known to happen. So I queued the fix for 5.18-rc1, cc:stable.
Triggering that registration error is fairly hard, usually we fail memory hotplug because we fail to allocate the (largish) memmap. So I am not aware that this BUG actually triggered.
On Mon 31-01-22 17:01:23, Andrew Morton wrote:
On Fri, 28 Jan 2022 15:45:40 +0100 David Hildenbrand david@redhat.com wrote:
If register_memory() fails, we freed the memory block but already added the memory block to the group list, not good. Let's defer adding the block to the memory group to after registering the memory block device.
We do handle it properly during unregister_memory(), but that's not called when the registration fails.
I guess this has never been known to happen. So I queued the fix for 5.18-rc1, cc:stable.
I do not think this is worth stable backporting. Chances of a failure are pretty small and I am not aware of any existing report.
On Fri 28-01-22 15:45:40, David Hildenbrand wrote:
If register_memory() fails, we freed the memory block but already added the memory block to the group list, not good. Let's defer adding the block to the memory group to after registering the memory block device.
We do handle it properly during unregister_memory(), but that's not called when the registration fails.
Fixes: 028fc57a1c36 ("drivers/base/memory: introduce "memory groups" to logically group memory blocks") Cc: stable@vger.kernel.org # v5.15+ Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: "Rafael J. Wysocki" rafael@kernel.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: Oscar Salvador osalvador@suse.de Signed-off-by: David Hildenbrand david@redhat.com
Acked-by: Michal Hocko mhocko@suse.com
Thanks!
drivers/base/memory.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 365cd4a7f239..60c38f9cf1a7 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -663,14 +663,16 @@ static int init_memory_block(unsigned long block_id, unsigned long state, mem->nr_vmemmap_pages = nr_vmemmap_pages; INIT_LIST_HEAD(&mem->group_next);
- ret = register_memory(mem);
- if (ret)
return ret;- if (group) { mem->group = group; list_add(&mem->group_next, &group->memory_blocks); }
- ret = register_memory(mem);
- return ret;
- return 0;
} static int add_memory_block(unsigned long base_section_nr) -- 2.34.1
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Andrew Morton -
David Hildenbrand -
Michal Hocko -
Oscar Salvador