diff options
| author | Tejun Heo <tj@kernel.org> | 2024-06-18 10:09:16 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2024-06-18 10:09:16 -1000 |
| commit | 304b3f2bc07ba7c74a1ebc7917a8f0549e6b8d54 (patch) | |
| tree | 582484f486f8bfb72c9d02c59f9fe5eb3e63b3bd /kernel/fork.c | |
| parent | df268382adc1f7aa3ad92f7de71b70395f24e4e7 (diff) | |
sched: Allow sched_cgroup_fork() to fail and introduce sched_cancel_fork()
A new BPF extensible sched_class will need more control over the forking
process. It wants to be able to fail from sched_cgroup_fork() after the new
task's sched_task_group is initialized so that the loaded BPF program can
prepare the task with its cgroup association is established and reject fork
if e.g. allocation fails.
Allow sched_cgroup_fork() to fail by making it return int instead of void
and adding sched_cancel_fork() to undo sched_fork() in the error path.
sched_cgroup_fork() doesn't fail yet and this patch shouldn't cause any
behavior changes.
v2: Patch description updated to detail the expected use.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: David Vernet <dvernet@meta.com>
Acked-by: Josh Don <joshdon@google.com>
Acked-by: Hao Luo <haoluo@google.com>
Acked-by: Barret Rhoden <brho@google.com>
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 99076dbe27d8..e601fdf787c3 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2363,7 +2363,7 @@ __latent_entropy struct task_struct *copy_process( retval = perf_event_init_task(p, clone_flags); if (retval) - goto bad_fork_cleanup_policy; + goto bad_fork_sched_cancel_fork; retval = audit_alloc(p); if (retval) goto bad_fork_cleanup_perf; @@ -2496,7 +2496,9 @@ __latent_entropy struct task_struct *copy_process( * cgroup specific, it unconditionally needs to place the task on a * runqueue. */ - sched_cgroup_fork(p, args); + retval = sched_cgroup_fork(p, args); + if (retval) + goto bad_fork_cancel_cgroup; /* * From this point on we must avoid any synchronous user-space @@ -2542,13 +2544,13 @@ __latent_entropy struct task_struct *copy_process( /* Don't start children in a dying pid namespace */ if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) { retval = -ENOMEM; - goto bad_fork_cancel_cgroup; + goto bad_fork_core_free; } /* Let kill terminate clone/fork in the middle */ if (fatal_signal_pending(current)) { retval = -EINTR; - goto bad_fork_cancel_cgroup; + goto bad_fork_core_free; } /* No more failure paths after this point. */ @@ -2622,10 +2624,11 @@ __latent_entropy struct task_struct *copy_process( return p; -bad_fork_cancel_cgroup: +bad_fork_core_free: sched_core_free(p); spin_unlock(¤t->sighand->siglock); write_unlock_irq(&tasklist_lock); +bad_fork_cancel_cgroup: cgroup_cancel_fork(p, args); bad_fork_put_pidfd: if (clone_flags & CLONE_PIDFD) { @@ -2664,6 +2667,8 @@ bad_fork_cleanup_audit: audit_free(p); bad_fork_cleanup_perf: perf_event_free_task(p); +bad_fork_sched_cancel_fork: + sched_cancel_fork(p); bad_fork_cleanup_policy: lockdep_free_task(p); #ifdef CONFIG_NUMA |