Bug 210213
| Summary: | vCPUs >= 64 can't be online and hotplugged in some scenarios | ||
|---|---|---|---|
| Product: | Virtualization | Reporter: | Zelin Deng (zelin.deng) |
| Component: | kvm | Assignee: | virtualization_kvm |
| Status: | NEW --- | ||
| Severity: | normal | ||
| Priority: | P1 | ||
| Hardware: | x86-64 | ||
| OS: | Linux | ||
| Kernel Version: | 5.10-rc4 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: | Here is a workaround to fix this issue | ||
Created attachment 293685 [details] Here is a workaround to fix this issue In VM, if no-kvmclock-vsyscall is set, lscpu shows online 0-63 vcpus are online vcpus >= 64 are offline and if we attempting to hotplug them, they will return -ENOMEM. This issue also happened in VM which are on TSC unstable host. bash-14295 [040] .... 64209.953702: cpuhp_enter: cpu: 0064 target: 199 step: 64 (kvmclock_setup_percpu) bash-14295 [040] .... 64209.953702: cpuhp_exit: cpu: 0064 state: 64 step: 64 ret: -12 ---------------------------- [root@iZwz9208df47apaoyvbmm3Z processor]# cat /sys/kernel/debug/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 166/166 #P:49 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | bash-14295 [040] .... 64209.953675: cpuhp_enter: cpu: 0064 target: 199 step: 1 (smpboot_create_threads) bash-14295 [040] .... 64209.953676: cpuhp_exit: cpu: 0064 state: 1 step: 1 ret: 0 bash-14295 [040] .... 64209.953676: cpuhp_enter: cpu: 0064 target: 199 step: 2 (perf_event_init_cpu) bash-14295 [040] .... 64209.953677: cpuhp_exit: cpu: 0064 state: 2 step: 2 ret: 0 bash-14295 [040] .... 64209.953678: cpuhp_enter: cpu: 0064 target: 199 step: 35 (workqueue_prepare_cpu) bash-14295 [040] .... 64209.953678: cpuhp_exit: cpu: 0064 state: 35 step: 35 ret: 0 bash-14295 [040] .... 64209.953678: cpuhp_enter: cpu: 0064 target: 199 step: 37 (hrtimers_prepare_cpu) bash-14295 [040] .... 64209.953679: cpuhp_exit: cpu: 0064 state: 37 step: 37 ret: 0 bash-14295 [040] .... 64209.953679: cpuhp_enter: cpu: 0064 target: 199 step: 40 (smpcfd_prepare_cpu) bash-14295 [040] .... 64209.953692: cpuhp_exit: cpu: 0064 state: 40 step: 40 ret: 0 bash-14295 [040] .... 64209.953693: cpuhp_enter: cpu: 0064 target: 199 step: 41 (relay_prepare_cpu) bash-14295 [040] .... 64209.953693: cpuhp_exit: cpu: 0064 state: 41 step: 41 ret: 0 bash-14295 [040] .... 64209.953693: cpuhp_enter: cpu: 0064 target: 199 step: 44 (rcutree_prepare_cpu) bash-14295 [040] .... 64209.953694: cpuhp_exit: cpu: 0064 state: 44 step: 44 ret: 0 bash-14295 [040] .... 64209.953694: cpuhp_enter: cpu: 0064 target: 199 step: 53 (topology_add_dev) bash-14295 [040] .... 64209.953699: cpuhp_exit: cpu: 0064 state: 53 step: 53 ret: 0 bash-14295 [040] .... 64209.953700: cpuhp_multi_enter: cpu: 0064 target: 199 step: 56 (trace_rb_cpu_prepare) bash-14295 [040] .... 64209.953700: cpuhp_exit: cpu: 0064 state: 56 step: 56 ret: 0 bash-14295 [040] .... 64209.953700: cpuhp_multi_enter: cpu: 0064 target: 199 step: 56 (trace_rb_cpu_prepare) bash-14295 [040] .... 64209.953700: cpuhp_exit: cpu: 0064 state: 56 step: 56 ret: 0 bash-14295 [040] .... 64209.953701: cpuhp_multi_enter: cpu: 0064 target: 199 step: 56 (trace_rb_cpu_prepare) bash-14295 [040] .... 64209.953701: cpuhp_exit: cpu: 0064 state: 56 step: 56 ret: 0 bash-14295 [040] .... 64209.953701: cpuhp_enter: cpu: 0064 target: 199 step: 62 (timers_prepare_cpu) bash-14295 [040] .... 64209.953701: cpuhp_exit: cpu: 0064 state: 62 step: 62 ret: 0 bash-14295 [040] .... 64209.953702: cpuhp_enter: cpu: 0064 target: 199 step: 64 (kvmclock_setup_percpu) bash-14295 [040] .... 64209.953702: cpuhp_exit: cpu: 0064 state: 64 step: 64 ret: -12