diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/ext/ext.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index a9621bbdb183..3c3fb8c18eab 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -11831,6 +11831,22 @@ static const struct btf_kfunc_id_set scx_kfunc_set_any = { }; /* + * Kfuncs which may take the rq lock on their unlocked path. + * + * A tracing program can execute in any kernel context, including ones which + * already hold the rq lock (e.g. sched_switch). scx_locked_rq() only tracks + * rq locks taken for SCX callbacks, so from such a context it returns NULL + * and these kfuncs would acquire the already held rq lock again and deadlock + * the CPU. They cannot be made safe for tracing programs, so keep them off + * the tracing hook. Members must also stay in scx_kfunc_ids_any so that + * struct_ops and syscall programs keep their access. + */ +BTF_KFUNCS_START(scx_kfunc_ids_no_tracing) +BTF_ID_FLAGS(func, scx_bpf_cpuperf_set, KF_IMPLICIT_ARGS) +BTF_ID_FLAGS(func, scx_bpf_cidperf_set, KF_IMPLICIT_ARGS) +BTF_KFUNCS_END(scx_kfunc_ids_no_tracing) + +/* * cpu-form kfuncs that are forbidden from cid-form schedulers * (bpf_sched_ext_ops_cid). Programs targeting the cid struct_ops type must * use the cid-form alternative (cid/cmask kfuncs). @@ -11938,6 +11954,7 @@ int scx_kfunc_context_filter(const struct bpf_prog *prog, u32 kfunc_id) bool in_any = btf_id_set8_contains(&scx_kfunc_ids_any, kfunc_id); bool in_cpu_only = btf_id_set8_contains(&scx_kfunc_ids_cpu_only, kfunc_id); bool in_cid = btf_id_set8_contains(&scx_kfunc_ids_cid, kfunc_id); + bool in_no_tracing = btf_id_set8_contains(&scx_kfunc_ids_no_tracing, kfunc_id); u32 moff, flags; /* Not an SCX kfunc - allow. */ @@ -11950,7 +11967,7 @@ int scx_kfunc_context_filter(const struct bpf_prog *prog, u32 kfunc_id) return (in_unlocked || in_select_cpu || in_idle || in_any || in_cid) ? 0 : -EACCES; if (prog->type != BPF_PROG_TYPE_STRUCT_OPS) - return (in_any || in_idle || in_cid) ? 0 : -EACCES; + return (!in_no_tracing && (in_any || in_idle || in_cid)) ? 0 : -EACCES; /* * add_subprog_and_kfunc() collects all kfunc calls, including dead code |