On Tue 07-07-20 13:59:17, 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@xxxxxxxxxxxxxxx # v5.6+
> Signed-off-by: Jia He <justin.he@xxxxxxx>
Ups, I have missed that when reviewing that commit. Thanks for catching
this up!
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
> 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 da374cd3d45b..76c75a599da3 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1742,7 +1742,7 @@ 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");
> @@ -1766,9 +1766,8 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size)
>
> try_offline_node(nid);
>
> -done:
> mem_hotplug_done();
> - return rc;
> + return 0;
> }
>
> /**
> --
> 2.17.1
--
Michal Hocko
SUSE Labs
