From: WuJianguo <wujianguo@xxxxxxxxxx> When handling a memory node with only movable zone, function early_kmem_cache_node_alloc() will allocate a page from remote node but still increase object count on local node, which will trigger a BUG_ON() as below when hot-removing this memory node. Actually there's no need to create kmem_cache_node for memory node with only movable zone at all. ------------[ cut here ]------------ kernel BUG at mm/slub.c:3590! invalid opcode: 0000 [#1] SMP CPU 61 Modules linked in: autofs4 sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables ipv6 vfat fat dm_mirror dm_region_hash dm_log uinput iTCO_wdt iTCO_vendor_support coretemp hwmon kvm_intel kvm crc32c_intel ghash_clmulni_intel serio_raw pcspkr cdc_ether usbnet mii i2c_i801 i2c_core sg lpc_ich mfd_core shpchp ioatdma i7core_edac edac_core igb dca bnx2 ext4 mbcache jbd2 sr_mod cdrom sd_mod crc_t10dif aesni_intel cryptd aes_x86_64 aes_generic bfa scsi_transport_fc scsi_tgt pata_acpi ata_generic ata_piix megaraid_sas dm_mod [last unloaded: microcode] Pid: 46287, comm: sh Not tainted 3.5.0-rc4-pgtable-00215-g35f0828-dirty #85 IBM System x3850 X5 -[7143O3G]-/Node 1, Processor Card RIP: 0010:[<ffffffff81160b2a>] [<ffffffff81160b2a>] slab_memory_callback+0x1ba/0x1c0 RSP: 0018:ffff880efdcb7c68 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffff880f7ec06100 RCX: 0000000100400001 RDX: 0000000100400002 RSI: ffff880f7ec02000 RDI: ffff880f7ec06100 RBP: ffff880efdcb7c78 R08: ffff88107b6fb098 R09: ffffffff81160a00 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000019 R13: 00000000fffffffb R14: 0000000000000000 R15: ffffffff81abe930 FS: 00007f709f342700(0000) GS:ffff880f7f3a0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000003b5a874570 CR3: 0000000f0da20000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sh (pid: 46287, threadinfo ffff880efdcb6000, task ffff880f0fa50000) Stack: 0000000000000004 ffff880efdcb7da8 ffff880efdcb7cb8 ffffffff81524af5 0000000000000001 ffffffff81a8b620 ffffffff81a8b640 0000000000000004 ffff880efdcb7da8 00000000ffffffff ffff880efdcb7d08 ffffffff8107a89a Call Trace: [<ffffffff81524af5>] notifier_call_chain+0x55/0x80 [<ffffffff8107a89a>] __blocking_notifier_call_chain+0x5a/0x80 [<ffffffff8107a8d6>] blocking_notifier_call_chain+0x16/0x20 [<ffffffff81352f0b>] memory_notify+0x1b/0x20 [<ffffffff81507104>] offline_pages+0x624/0x700 [<ffffffff811619de>] remove_memory+0x1e/0x20 [<ffffffff813530cc>] memory_block_change_state+0x13c/0x2e0 [<ffffffff81153e96>] ? alloc_pages_current+0xb6/0x120 [<ffffffff81353332>] store_mem_state+0xc2/0xd0 [<ffffffff8133e190>] dev_attr_store+0x20/0x30 [<ffffffff811e2d4f>] sysfs_write_file+0xef/0x170 [<ffffffff81173e28>] vfs_write+0xc8/0x190 [<ffffffff81173ff1>] sys_write+0x51/0x90 [<ffffffff81528d29>] system_call_fastpath+0x16/0x1b Code: 8b 3d cb fd c4 00 be d0 00 00 00 e8 71 de ff ff 48 85 c0 75 9c 48 c7 c7 c0 7f a5 81 e8 c0 89 f1 ff b8 0d 80 00 00 e9 69 fe ff ff <0f> 0b eb fe 66 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 RIP [<ffffffff81160b2a>] slab_memory_callback+0x1ba/0x1c0 RSP <ffff880efdcb7c68> ---[ end trace 749e9e9a67c78c12 ]--- Signed-off-by: Jianguo Wu <wujianguo@xxxxxxxxxx> Signed-off-by: Jiang Liu <liuj97@xxxxxxxxx> --- mm/slub.c | 44 +++++++++++++++++++++++++++++++++----------- 1 files changed, 33 insertions(+), 11 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 8c691fa..3976745 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2803,6 +2803,17 @@ static inline int alloc_kmem_cache_cpus(struct kmem_cache *s) static struct kmem_cache *kmem_cache_node; +static bool node_has_normal_memory(int node) +{ + int i; + + for (i = ZONE_NORMAL; i >= 0; i--) + if (populated_zone(&NODE_DATA(node)->node_zones[i])) + return true; + + return false; +} + /* * No kmalloc_node yet so do it by hand. We know that this is the first * slab on the node for this slabcache. There are no concurrent accesses @@ -2866,6 +2877,10 @@ static int init_kmem_cache_nodes(struct kmem_cache *s) for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n; + /* Do not create kmem_cache_node for node without normal memory */ + if (!node_has_normal_memory(node)) + continue; + if (slab_state == DOWN) { early_kmem_cache_node_alloc(node); continue; @@ -3178,9 +3193,11 @@ static inline int kmem_cache_close(struct kmem_cache *s) for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); - free_partial(s, n); - if (n->nr_partial || slabs_node(s, node)) - return 1; + if (n) { + free_partial(s, n); + if (n->nr_partial || slabs_node(s, node)) + return 1; + } } free_kmem_cache_nodes(s); return 0; @@ -3509,7 +3526,7 @@ int kmem_cache_shrink(struct kmem_cache *s) for_each_node_state(node, N_NORMAL_MEMORY) { n = get_node(s, node); - if (!n->nr_partial) + if (!n || !n->nr_partial) continue; for (i = 0; i < objects; i++) @@ -4170,7 +4187,8 @@ static long validate_slab_cache(struct kmem_cache *s) for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); - count += validate_slab_node(s, n, map); + if (n) + count += validate_slab_node(s, n, map); } kfree(map); return count; @@ -4339,7 +4357,7 @@ static int list_locations(struct kmem_cache *s, char *buf, unsigned long flags; struct page *page; - if (!atomic_long_read(&n->nr_slabs)) + if (!n || !atomic_long_read(&n->nr_slabs)) continue; spin_lock_irqsave(&n->list_lock, flags); @@ -4534,11 +4552,13 @@ static ssize_t show_slab_objects(struct kmem_cache *s, for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); - if (flags & SO_TOTAL) - x = atomic_long_read(&n->total_objects); - else if (flags & SO_OBJECTS) - x = atomic_long_read(&n->total_objects) - - count_partial(n, count_free); + if (!n) + continue; + if (flags & SO_TOTAL) + x = atomic_long_read(&n->total_objects); + else if (flags & SO_OBJECTS) + x = atomic_long_read(&n->total_objects) - + count_partial(n, count_free); else x = atomic_long_read(&n->nr_slabs); @@ -4552,6 +4572,8 @@ static ssize_t show_slab_objects(struct kmem_cache *s, for_each_node_state(node, N_NORMAL_MEMORY) { struct kmem_cache_node *n = get_node(s, node); + if (!n) + continue; if (flags & SO_TOTAL) x = count_partial(n, count_total); else if (flags & SO_OBJECTS) -- 1.7.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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