From: Jia He <justin.he@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Jia He <justin.he@arm.com>, Baoquan He <bhe@redhat.com>,
Kaly Xin <Kaly.Xin@arm.com>, Chuhong Yuan <hslester96@gmail.com>,
linux-kernel@vger.kernel.org, Mike Rapoport <rppt@linux.ibm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/3] mm/memory_hotplug: harden try_offline_node against bogus nid
Date: Mon, 6 Jul 2020 09:19:46 +0800 [thread overview]
Message-ID: <20200706011947.184166-3-justin.he@arm.com> (raw)
In-Reply-To: <20200706011947.184166-1-justin.he@arm.com>
When testing the remove_memory path of dax pmem, there will be a panic with
call trace:
try_remove_memory+0x84/0x170
remove_memory+0x38/0x58
dev_dax_kmem_remove+0x3c/0x84 [kmem]
device_release_driver_internal+0xfc/0x1c8
device_release_driver+0x28/0x38
bus_remove_device+0xd4/0x158
device_del+0x160/0x3a0
unregister_dev_dax+0x30/0x68
devm_action_release+0x20/0x30
release_nodes+0x150/0x240
devres_release_all+0x6c/0x1d0
device_release_driver_internal+0x10c/0x1c8
driver_detach+0xac/0x170
bus_remove_driver+0x64/0x130
driver_unregister+0x34/0x60
dax_pmem_exit+0x14/0xffc4 [dax_pmem]
__arm64_sys_delete_module+0x18c/0x2d0
el0_svc_common.constprop.2+0x78/0x168
do_el0_svc+0x34/0xa0
el0_sync_handler+0xe0/0x188
el0_sync+0x164/0x180
It is caused by the bogus nid (-1). Although the root cause is pmem dax
translates from pxm to node_id incorrectly due to numa_off, it is worth
hardening the codes in try_offline_node(), quiting if !pgdat.
Signed-off-by: Jia He <justin.he@arm.com>
---
mm/memory_hotplug.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index da374cd3d45b..e1e290577b45 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1680,6 +1680,9 @@ void try_offline_node(int nid)
pg_data_t *pgdat = NODE_DATA(nid);
int rc;
+ if (WARN_ON(!pgdat))
+ return;
+
/*
* If the node still spans pages (especially ZONE_DEVICE), don't
* offline it. A node spans memory after move_pfn_range_to_zone(),
--
2.17.1
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next prev parent reply other threads:[~2020-07-06 1:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-06 1:19 [PATCH 0/3] Fix and enable pmem as RAM on arm64 Jia He
2020-07-06 1:19 ` [PATCH 1/3] arm64/numa: set numa_off to false when numa node is fake Jia He
2020-07-06 8:02 ` David Hildenbrand
2020-07-06 12:36 ` Justin He
2020-07-06 13:56 ` David Hildenbrand
2020-07-06 10:29 ` Jonathan Cameron
2020-07-06 10:46 ` Jonathan Cameron
2020-07-06 12:47 ` Justin He
2020-07-06 13:03 ` Jonathan Cameron
2020-07-06 1:19 ` Jia He [this message]
2020-07-06 7:57 ` [PATCH 2/3] mm/memory_hotplug: harden try_offline_node against bogus nid David Hildenbrand
2020-07-06 13:45 ` Justin He
2020-07-06 1:19 ` [PATCH 3/3] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done Jia He
2020-07-06 7:49 ` David Hildenbrand
2020-07-07 22:10 ` Dan Williams
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