The warning introduced in commit: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups") assumed that a cgroup switch always precedes list_del_event. This is not the case. Remove warning. Make sure that cpuctx->cgrp is NULL until a cgroup event is sched in or ctx->nr_cgroups == 0.
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| @@ -903,17 +903,14 @@ list_update_cgroup_event(struct perf_event *event, · 902 unmodified lines | |||
| 903 | */ | 903 | */ |
| 904 | cpuctx = __get_cpu_context(ctx); | 904 | cpuctx = __get_cpu_context(ctx); |
| 905 | 905 | ||
| 906 | /* Only set/clear cpuctx->cgrp if current task uses event->cgrp. */ | 906 | /* |
| 907 | if (perf_cgroup_from_task(current, ctx) != event->cgrp) { | 907 | * cpuctx->cgrp is NULL until a cgroup event is sched in or |
| 908 | /* | 908 | * ctx->nr_cgroup == 0 . |
| 909 | * We are removing the last cpu event in this context. | 909 | */ |
| 910 | * If that event is not active in this cpu, cpuctx->cgrp | 910 | if (add && perf_cgroup_from_task(current, ctx) == event->cgrp) |
| 911 | * should've been cleared by perf_cgroup_switch. | 911 | cpuctx->cgrp = event->cgrp; |
| 912 | */ | 912 | else if (!add) |
| 913 | WARN_ON_ONCE(!add && cpuctx->cgrp); | 913 | cpuctx->cgrp = NULL; |
| 914 | return; | ||
| 915 | } | ||
| 916 | cpuctx->cgrp = add ? event->cgrp : NULL; | ||
| 917 | } | 914 | } |
| 918 | 915 | ||
| 919 | #else /* !CONFIG_CGROUP_PERF */ | 916 | #else /* !CONFIG_CGROUP_PERF */ |