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From:   David Hildenbrand <david@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@kernel.org>,
        Michal Hocko <mhocko@suse.com>,
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        Jianyong Wu <Jianyong.Wu@arm.com>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        Vineet Gupta <vgupta@kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Huacai Chen <chenhuacai@kernel.org>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Heiko Carstens <hca@linux.ibm.com>,
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        Eric Biederman <ebiederm@xmission.com>,
        Arnd Bergmann <arnd@arndb.de>,
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        kexec@lists.infradead.org
Subject: [PATCH v1 1/4] mm/memory_hotplug: handle memblock_add_node() failures in add_memory_resource()
Date:   Mon, 27 Sep 2021 17:05:15 +0200
Message-Id: <20210927150518.8607-2-david@redhat.com>
In-Reply-To: <20210927150518.8607-1-david@redhat.com>
References: <20210927150518.8607-1-david@redhat.com>
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If memblock_add_node() fails, we're most probably running out of memory.
While this is unlikely to happen, it can happen and having memory added
without a memblock can be problematic for architectures that use
memblock to detect valid memory. Let's fail in a nice way instead of
silently ignoring the error.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/memory_hotplug.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 9fd0be32a281..917b3528636d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1384,8 +1384,11 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
 
 	mem_hotplug_begin();
 
-	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
-		memblock_add_node(start, size, nid);
+	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
+		ret = memblock_add_node(start, size, nid);
+		if (ret)
+			goto error_mem_hotplug_end;
+	}
 
 	ret = __try_online_node(nid, false);
 	if (ret < 0)
@@ -1458,6 +1461,7 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
 		rollback_node_hotadd(nid);
 	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
 		memblock_remove(start, size);
+error_mem_hotplug_end:
 	mem_hotplug_done();
 	return ret;
 }
-- 
2.31.1