FAILED: patch "[PATCH] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done" failed to apply to 4.19-stable tree - Linux-stable-mirror

19 Aug 2020

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
...
From b4223a510e2ab1bf0f971d50af7c1431014b25ad Mon Sep 17 00:00:00 2001
From: Jia He justin.he@arm.com
Date: Tue, 11 Aug 2020 18:32:20 -0700
Subject: [PATCH] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done
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")
Signed-off-by: Jia He justin.he@arm.com
Signed-off-by: Andrew Morton akpm@linux-foundation.org
Reviewed-by: David Hildenbrand david@redhat.com
Acked-by: Michal Hocko mhocko@suse.com
Acked-by: Dan Williams dan.j.williams@intel.com
Cc: stable@vger.kernel.org	[5.6+]
Cc: Andy Lutomirski luto@kernel.org
Cc: Baoquan He bhe@redhat.com
Cc: Borislav Petkov bp@alien8.de
Cc: Catalin Marinas catalin.marinas@arm.com
Cc: Chuhong Yuan hslester96@gmail.com
Cc: Dave Hansen dave.hansen@linux.intel.com
Cc: Dave Jiang dave.jiang@intel.com
Cc: Fenghua Yu fenghua.yu@intel.com
Cc: "H. Peter Anvin" hpa@zytor.com
Cc: Ingo Molnar mingo@redhat.com
Cc: Jonathan Cameron Jonathan.Cameron@Huawei.com
Cc: Kaly Xin Kaly.Xin@arm.com
Cc: Logan Gunthorpe logang@deltatee.com
Cc: Masahiro Yamada masahiroy@kernel.org
Cc: Mike Rapoport rppt@linux.ibm.com
Cc: Peter Zijlstra peterz@infradead.org
Cc: Rich Felker dalias@libc.org
Cc: Thomas Gleixner tglx@linutronix.de
Cc: Tony Luck tony.luck@intel.com
Cc: Vishal Verma vishal.l.verma@intel.com
Cc: Will Deacon will@kernel.org
Cc: Yoshinori Sato ysato@users.sourceforge.jp
Link: http://lkml.kernel.org/r/20200710031619.18762-3-justin.he@arm.com
Signed-off-by: Linus Torvalds torvalds@linux-foundation.org

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 6289a909ea36..ce3d858319bd 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1757,7 +1757,7 @@ 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");
@@ -1781,9 +1781,8 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size)
try_offline_node(nid);
-done:
    mem_hotplug_done();
-	return rc;
+	return 0;
 }
/**

    