[PATCH 0/2] Update cpu_cpu_mask on CPU online/offline

[Srikar Dronamraju]

When simultaneously running CPU online/offline with CPU add/remove in a
loop, we see a WARNING messages.

WARNING: CPU: 13 PID: 1142 at kernel/sched/topology.c:898 build_sched_domains+0xd48/0x1720
Modules linked in: rpadlpar_io rpaphp mptcp_diag xsk_diag tcp_diag udp_diag
raw_diag inet_diag unix_diag af_packet_diag netlink_diag bonding tls
nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet
nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat
nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set rfkill nf_tables nfnetlink
pseries_rng xts vmx_crypto uio_pdrv_genirq uio binfmt_misc ip_tables xfs
libcrc32c dm_service_time sd_mod t10_pi sg ibmvfc scsi_transport_fc ibmveth
dm_multipath dm_mirror dm_region_hash dm_log dm_mod fuse
CPU: 13 PID: 1142 Comm: kworker/13:2 Not tainted 5.13.0-rc6+ #28
Workqueue: events cpuset_hotplug_workfn
NIP:  c0000000001caac8 LR: c0000000001caac4 CTR: 00000000007088ec
REGS: c00000005596f220 TRAP: 0700   Not tainted  (5.13.0-rc6+)
MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 48828222  XER: 00000009
CFAR: c0000000001ea698 IRQMASK: 0
GPR00: c0000000001caac4 c00000005596f4c0 c000000001c4a400 0000000000000036
GPR04: 00000000fffdffff c00000005596f1d0 0000000000000027 c0000018cfd07f90
GPR08: 0000000000000023 0000000000000001 0000000000000027 c0000018fe68ffe8
GPR12: 0000000000008000 c00000001e9d1880 c00000013a047200 0000000000000800
GPR16: c000000001d3c7d0 0000000000000240 0000000000000048 c000000010aacd18
GPR20: 0000000000000001 c000000010aacc18 c00000013a047c00 c000000139ec2400
GPR24: 0000000000000280 c000000139ec2520 c000000136c1b400 c000000001c93060
GPR28: c00000013a047c20 c000000001d3c6c0 c000000001c978a0 000000000000000d
NIP [c0000000001caac8] build_sched_domains+0xd48/0x1720
LR [c0000000001caac4] build_sched_domains+0xd44/0x1720
Call Trace:
[c00000005596f4c0] [c0000000001caac4] build_sched_domains+0xd44/0x1720 (unreliable)
[c00000005596f670] [c0000000001cc5ec] partition_sched_domains_locked+0x3ac/0x4b0
[c00000005596f710] [c0000000002804e4] rebuild_sched_domains_locked+0x404/0x9e0
[c00000005596f810] [c000000000283e60] rebuild_sched_domains+0x40/0x70
[c00000005596f840] [c000000000284124] cpuset_hotplug_workfn+0x294/0xf10
[c00000005596fc60] [c000000000175040] process_one_work+0x290/0x590
[c00000005596fd00] [c0000000001753c8] worker_thread+0x88/0x620
[c00000005596fda0] [c000000000181704] kthread+0x194/0x1a0
[c00000005596fe10] [c00000000000ccec] ret_from_kernel_thread+0x5c/0x70
Instruction dump:
485af049 60000000 2fa30800 409e0028 80fe0000 e89a00f8 e86100e8 38da0120
7f88e378 7ce53b78 4801fb91 60000000 <0fe00000> 39000000 38e00000 38c00000

This was because cpu_cpu_mask() was not getting updated on CPU
online/offline but would be only updated when add/remove of CPUs.
Other cpumasks get updated both on CPU online/offline and add/remove
Update cpu_cpu_mask() on CPU online/offline too.

Cc: linuxppc-dev at lists.ozlabs.org
Cc: Nathan Lynch <nathanl at linux.ibm.com>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Ingo Molnar <mingo at kernel.org>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Valentin Schneider <valentin.schneider at arm.com>
Cc: Gautham R Shenoy <ego at linux.vnet.ibm.com>
Cc: Vincent Guittot <vincent.guittot at linaro.org>
Cc: Geetika Moolchandani <Geetika.Moolchandani1 at ibm.com>
Cc: Laurent Dufour <ldufour at linux.ibm.com>

Srikar Dronamraju (2):
  powerpc/numa: Print debug statements only when required
  powerpc/numa: Update cpu_cpu_map on CPU online/offline

 arch/powerpc/include/asm/topology.h | 12 ++++++++++++
 arch/powerpc/kernel/smp.c           |  3 +++
 arch/powerpc/mm/numa.c              | 18 +++++++-----------
 3 files changed, 22 insertions(+), 11 deletions(-)

-- 
2.27.0