From 888e396a7a1d2219cc01465f7b757d892d7260a9 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 25 Aug 2022 14:50:19 +0530 Subject: [PATCH] mm/demotion: fix kernel error with memory hotplug On memory hot unplug, the kernel removes the node memory type from the associated memory tier. Use list_del_init instead of list del such that the same memory type can be added back to a memory tier on hotplug. Without this, we get the below warning and return error on adding memory type to a new memory tier. [ 33.596095] ------------[ cut here ]------------ [ 33.596099] WARNING: CPU: 3 PID: 667 at mm/memory-tiers.c:115 set_node_memory_tier+0xd6/0x2e0 [ 33.596109] Modules linked in: kmem ... [ 33.596126] RIP: 0010:set_node_memory_tier+0xd6/0x2e0 .... [ 33.596196] memtier_hotplug_callback+0x48/0x68 [ 33.596204] blocking_notifier_call_chain+0x80/0xc0 [ 33.596211] online_pages+0x25e/0x280 [ 33.596218] memory_block_change_state+0x176/0x1f0 [ 33.596225] memory_subsys_online+0x37/0x40 [ 33.596230] online_store+0x9b/0x130 [ 33.596236] kernfs_fop_write_iter+0x128/0x1b0 [ 33.596242] vfs_write+0x24b/0x2c0 [ 33.596249] ksys_write+0x74/0xe0 [ 33.596254] do_syscall_64+0x43/0x90 [ 33.596259] entry_SYSCALL_64_after_hwframe+0x63/0xcd Link: https://lkml.kernel.org/r/20220825092019.379069-1-aneesh.kumar@linux.ibm.com Fixes: "mm/demotion: Add hotplug callbacks to handle new numa node onlined" Signed-off-by: Aneesh Kumar K.V Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: "Huang, Ying" Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Wei Xu Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/memory-tiers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 05f05395468a..f74e077533ac 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -134,7 +134,7 @@ static bool clear_node_memory_tier(int node) memtype = node_memory_types[node]; node_clear(node, memtype->nodes); if (nodes_empty(memtype->nodes)) { - list_del(&memtype->tier_sibiling); + list_del_init(&memtype->tier_sibiling); memtype->memtier = NULL; if (list_empty(&memtier->memory_types)) destroy_memory_tier(memtier); -- 2.50.1