7900aa699c
sched_ext_free() was called from __put_task_struct() when the last reference to the task is dropped, which could be long after the task has finished running. This causes cgroup-related problems: - ops.init_task() can be called on a cgroup which didn't get ops.cgroup_init()'d during scheduler load, because the cgroup might be destroyed/unlinked while the zombie or dead task is still lingering on the scx_tasks list. - ops.cgroup_exit() could be called before ops.exit_task() is called on all member tasks, leading to incorrect exit ordering. Fix by moving it to finish_task_switch() to be called right after the final context switch away from the dying task, matching when sched_class->task_dead() is called. Rename it to sched_ext_dead() to match the new calling context. By calling sched_ext_dead() before cgroup_task_dead(), we ensure that: - Tasks visible on scx_tasks list have valid cgroups during scheduler load, as cgroup_mutex prevents cgroup destruction while the task is still linked. - All member tasks have ops.exit_task() called and are removed from scx_tasks before the cgroup can be destroyed and trigger ops.cgroup_exit(). This fix is made possible by the cgroup_task_dead() split in the previous patch. This also makes more sense resource-wise as there's no point in keeping scheduler side resources around for dead tasks. Reported-by: Dan Schatzberg <dschatzberg@meta.com> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
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| .. | ||
| affinity.h | ||
| autogroup.h | ||
| clock.h | ||
| cond_resched.h | ||
| coredump.h | ||
| cpufreq.h | ||
| cputime.h | ||
| deadline.h | ||
| debug.h | ||
| ext.h | ||
| hotplug.h | ||
| idle.h | ||
| init.h | ||
| isolation.h | ||
| jobctl.h | ||
| loadavg.h | ||
| mm.h | ||
| nohz.h | ||
| numa_balancing.h | ||
| posix-timers.h | ||
| prio.h | ||
| rseq_api.h | ||
| rt.h | ||
| sd_flags.h | ||
| signal.h | ||
| smt.h | ||
| stat.h | ||
| sysctl.h | ||
| task.h | ||
| task_flags.h | ||
| task_stack.h | ||
| thread_info_api.h | ||
| topology.h | ||
| types.h | ||
| user.h | ||
| vhost_task.h | ||
| wake_q.h | ||
| xacct.h | ||