On Thu, Aug 04, 2016 at 10:24:04AM +0100, Mel Gorman wrote: > Paul Mackerras and Reza Arbab reported that machines with memoryless nodes > fails when vmstats are refreshed. Paul reported an oops as follows > > [ 1.713998] Unable to handle kernel paging request for data at address 0xff7a10000 > [ 1.714164] Faulting instruction address: 0xc000000000270cd0 > [ 1.714304] Oops: Kernel access of bad area, sig: 11 [#1] > [ 1.714414] SMP NR_CPUS=2048 NUMA PowerNV > [ 1.714530] Modules linked in: > [ 1.714647] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.7.0-kvm+ #118 > [ 1.714786] task: c000000ff0680010 task.stack: c000000ff0704000 > [ 1.714926] NIP: c000000000270cd0 LR: c000000000270ce8 CTR: 0000000000000000 > [ 1.715093] REGS: c000000ff0707900 TRAP: 0300 Not tainted (4.7.0-kvm+) > [ 1.715232] MSR: 9000000102009033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE,TM[E]> CR: 846b6824 XER: 20000000 > [ 1.715748] CFAR: c000000000008768 DAR: 0000000ff7a10000 DSISR: 42000000 SOFTE: 1 > GPR00: c000000000270d08 c000000ff0707b80 c0000000011fb200 0000000000000000 > GPR04: 0000000000000800 0000000000000000 0000000000000000 0000000000000000 > GPR08: ffffffffffffffff 0000000000000000 0000000ff7a10000 c00000000122aae0 > GPR12: c000000000a1e440 c00000000fb80000 c00000000000c188 0000000000000000 > GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 > GPR20: 0000000000000000 0000000000000000 0000000000000000 c000000000cecad0 > GPR24: c000000000d035b8 c000000000d6cd18 c000000000d6cd18 c000001fffa86300 > GPR28: 0000000000000000 c000001fffa96300 c000000001230034 c00000000122eb18 > [ 1.717484] NIP [c000000000270cd0] refresh_zone_stat_thresholds+0x80/0x240 > [ 1.717568] LR [c000000000270ce8] refresh_zone_stat_thresholds+0x98/0x240 > [ 1.717648] Call Trace: > [ 1.717687] [c000000ff0707b80] [c000000000270d08] refresh_zone_stat_thresholds+0xb8/0x240 (unreliable) > > Both supplied potential fixes but one potentially misses checks and another > had redundant initialisations. This version initialises per_cpu_nodestats > on a per-pgdat basis instead of on a per-zone basis. > > Reported-by: Paul Mackerras <paulus@xxxxxxxxxx> > Reported-by: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> That works, thanks. Tested-by: Paul Mackerras <paulus@xxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>