linux-kernel - [PATCH 5.8 087/232] mm/memory_hotplug: fix unpaired mem_hotplug

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Message-Id: <20200820091617.036020693@linuxfoundation.org>
Date:   Thu, 20 Aug 2020 11:18:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jia He <justin.he@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Michal Hocko <mhocko@...e.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Andy Lutomirski <luto@...nel.org>, Baoquan He <bhe@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Catalin Marinas <catalin.marinas@....com>,
        Chuhong Yuan <hslester96@...il.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Kaly Xin <Kaly.Xin@....com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Rich Felker <dalias@...c.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Tony Luck <tony.luck@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Will Deacon <will@...nel.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 5.8 087/232] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done

From: Jia He <justin.he@....com>

commit b4223a510e2ab1bf0f971d50af7c1431014b25ad upstream.

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@....com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Reviewed-by: David Hildenbrand <david@...hat.com>
Acked-by: Michal Hocko <mhocko@...e.com>
Acked-by: Dan Williams <dan.j.williams@...el.com>
Cc: <stable@...r.kernel.org>	[5.6+]
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Baoquan He <bhe@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Chuhong Yuan <hslester96@...il.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Dave Jiang <dave.jiang@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc: Kaly Xin <Kaly.Xin@....com>
Cc: Logan Gunthorpe <logang@...tatee.com>
Cc: Masahiro Yamada <masahiroy@...nel.org>
Cc: Mike Rapoport <rppt@...ux.ibm.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rich Felker <dalias@...c.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Vishal Verma <vishal.l.verma@...el.com>
Cc: Will Deacon <will@...nel.org>
Cc: Yoshinori Sato <ysato@...rs.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200710031619.18762-3-justin.he@arm.com
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 mm/memory_hotplug.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1742,7 +1742,7 @@ static int __ref try_remove_memory(int n
 	 */
 	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 n

 	try_offline_node(nid);

-done:
 	mem_hotplug_done();
-	return rc;
+	return 0;
 }

 /**