[v3,6/6] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done
diff mbox series

Message ID 20200709020629.91671-7-justin.he@arm.com
State New
Headers show
Series
  • Fix and enable pmem as RAM device on arm64
Related show

Commit Message

Justin He July 9, 2020, 2:06 a.m. UTC
When check_memblock_offlined_cb() returns failed rc(e.g. the memblock is
online at that time), mem_hotplug_begin/done is unpaired in such case.

Therefore a warning:
 Call Trace:
  percpu_up_write+0x33/0x40
  try_remove_memory+0x66/0x120
  ? _cond_resched+0x19/0x30
  remove_memory+0x2b/0x40
  dev_dax_kmem_remove+0x36/0x72 [kmem]
  device_release_driver_internal+0xf0/0x1c0
  device_release_driver+0x12/0x20
  bus_remove_device+0xe1/0x150
  device_del+0x17b/0x3e0
  unregister_dev_dax+0x29/0x60
  devm_action_release+0x15/0x20
  release_nodes+0x19a/0x1e0
  devres_release_all+0x3f/0x50
  device_release_driver_internal+0x100/0x1c0
  driver_detach+0x4c/0x8f
  bus_remove_driver+0x5c/0xd0
  driver_unregister+0x31/0x50
  dax_pmem_exit+0x10/0xfe0 [dax_pmem]

Fixes: f1037ec0cc8a ("mm/memory_hotplug: fix remove_memory() lockdep splat")
Cc: stable@vger.kernel.org # v5.6+
Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
---
 mm/memory_hotplug.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

David Hildenbrand July 9, 2020, 9:11 a.m. UTC | #1
On 09.07.20 04:06, Jia He wrote:
> When check_memblock_offlined_cb() returns failed rc(e.g. the memblock is
> online at that time), mem_hotplug_begin/done is unpaired in such case.
> 
> Therefore a warning:
>  Call Trace:
>   percpu_up_write+0x33/0x40
>   try_remove_memory+0x66/0x120
>   ? _cond_resched+0x19/0x30
>   remove_memory+0x2b/0x40
>   dev_dax_kmem_remove+0x36/0x72 [kmem]
>   device_release_driver_internal+0xf0/0x1c0
>   device_release_driver+0x12/0x20
>   bus_remove_device+0xe1/0x150
>   device_del+0x17b/0x3e0
>   unregister_dev_dax+0x29/0x60
>   devm_action_release+0x15/0x20
>   release_nodes+0x19a/0x1e0
>   devres_release_all+0x3f/0x50
>   device_release_driver_internal+0x100/0x1c0
>   driver_detach+0x4c/0x8f
>   bus_remove_driver+0x5c/0xd0
>   driver_unregister+0x31/0x50
>   dax_pmem_exit+0x10/0xfe0 [dax_pmem]
> 
> Fixes: f1037ec0cc8a ("mm/memory_hotplug: fix remove_memory() lockdep splat")
> Cc: stable@vger.kernel.org # v5.6+
> Signed-off-by: Jia He <justin.he@arm.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Acked-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  mm/memory_hotplug.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index b49ab743d914..3e0645387daf 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1752,7 +1752,7 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size)
>  	 */
>  	rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
>  	if (rc)
> -		goto done;
> +		return rc;
>  
>  	/* remove memmap entry */
>  	firmware_map_remove(start, start + size, "System RAM");
> @@ -1776,9 +1776,8 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size)
>  
>  	try_offline_node(nid);
>  
> -done:
>  	mem_hotplug_done();
> -	return rc;
> +	return 0;
>  }
>  
>  /**
> 

@Andrew, can you pick that up directly? It's independent of the other stuff.

Patch
diff mbox series

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b49ab743d914..3e0645387daf 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1752,7 +1752,7 @@  static int __ref try_remove_memory(int nid, u64 start, u64 size)
 	 */
 	rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
 	if (rc)
-		goto done;
+		return rc;
 
 	/* remove memmap entry */
 	firmware_map_remove(start, start + size, "System RAM");
@@ -1776,9 +1776,8 @@  static int __ref try_remove_memory(int nid, u64 start, u64 size)
 
 	try_offline_node(nid);
 
-done:
 	mem_hotplug_done();
-	return rc;
+	return 0;
 }
 
 /**