mm/memory_hotplug.c: initialize per_cpu_nodestats for hotadded pgdats

rarbab · torvalds · commit 5830169f4726 · 2016-08-11T16:58:14.000-07:00
The following oops occurs after a pgdat is hotadded: Unable to handle kernel paging request for data at address 0x00c30001 Faulting instruction address: 0xc00000000022f8f4 Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=2048 NUMA pSeries Modules linked in: ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw iptable_filter nls_utf8 isofs sg virtio_balloon uio_pdrv_genirq uio ip_tables xfs libcrc32c sr_mod cdrom sd_mod virtio_net ibmvscsi scsi_transport_srp virtio_pci virtio_ring virtio dm_mirror dm_region_hash dm_log dm_mod CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.8.0-rc1-device torvalds#110 task: c000000000ef3080 task.stack: c000000000f6c000 NIP: c00000000022f8f4 LR: c00000000022f948 CTR: 0000000000000000 REGS: c000000000f6fa50 TRAP: 0300 Tainted: G W (4.8.0-rc1-device) MSR: 800000010280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]> CR: 84002028 XER: 20000000 CFAR: d000000001d2013c DAR: 0000000000c30001 DSISR: 40000000 SOFTE: 0 NIP refresh_cpu_vm_stats+0x1a4/0x2f0 LR refresh_cpu_vm_stats+0x1f8/0x2f0 Call Trace: refresh_cpu_vm_stats+0x1f8/0x2f0 (unreliable) Add per_cpu_nodestats initialization to the hotplug codepath. Link: http://lkml.kernel.org/r/1470931473-7090-1-git-send-email-arbab@linux.vnet.ibm.com Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
@@ -1219,6 +1219,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 
 	/* init node's zones as empty zones, we don't have any present pages.*/
 	free_area_init_node(nid, zones_size, start_pfn, zholes_size);
+	pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
 
 	/*
 	 * The node we allocated has no zone fallback lists. For avoiding
@@ -1249,6 +1250,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 {
 	arch_refresh_nodedata(nid, NULL);
+	free_percpu(pgdat->per_cpu_nodestats);
 	arch_free_nodedata(pgdat);
 	return;
 }

Original file line number	Diff line number	Diff line change
`@@ -1219,6 +1219,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)`
`1219`	`1219`
`1220`	`1220`	`/* init node's zones as empty zones, we don't have any present pages.*/`
`1221`	`1221`	`free_area_init_node(nid, zones_size, start_pfn, zholes_size);`
	`1222`	`+ pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);`
`1222`	`1223`
`1223`	`1224`	`/*`
`1224`	`1225`	`* The node we allocated has no zone fallback lists. For avoiding`
`@@ -1249,6 +1250,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)`
`1249`	`1250`	`static void rollback_node_hotadd(int nid, pg_data_t *pgdat)`
`1250`	`1251`	`{`
`1251`	`1252`	`arch_refresh_nodedata(nid, NULL);`
	`1253`	`+ free_percpu(pgdat->per_cpu_nodestats);`
`1252`	`1254`	`arch_free_nodedata(pgdat);`
`1253`	`1255`	`return;`
`1254`	`1256`	`}`