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@vger.kernel.org # v5.6+ Signed-off-by: Jia He justin.he@arm.com
Ups, I have missed that when reviewing that commit. Thanks for catching this up!
Acked-by: Michal Hocko mhocko@suse.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 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