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sched_ext: Gate cid kfuncs behind the SCX struct_ops check

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scx_bpf_cid_to_cpu(), scx_bpf_cpu_to_cid() and scx_bpf_cid_topo() live in
the scx_kfunc_ids_cid set, but scx_kfunc_context_filter() doesn't check
that set. The filter's first test treats any kfunc outside its known sets
as non-SCX and allows it, so these three kfuncs can be called from any
struct_ops program - e.g. a TCP congestion control program.

Add scx_kfunc_ids_cid to the filter's known sets, matching how in_any and
in_idle are handled.

Fixes: e9b55af47e ("sched_ext: Add topological CPU IDs (cids)")
Assisted-by: Z.ai:glm-5.2
Signed-off-by: fangqiurong <fangqiurong@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
fangqiurong
2026-08-12 14:11:16 +08:00
committed by Tejun Heo
parent 1be10bb070
commit 0c09d1ad81
2 changed files with 6 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
kernel/sched/ext/cid.h
View File

@@ -67,6 +67,7 @@ extern s32 __rcu *scx_shard_node;
extern struct scx_cid_shard __rcu *scx_cid_shard_ranges;
extern struct scx_cid_topo __rcu *scx_cid_topo;
extern struct btf_id_set8 scx_kfunc_ids_init_cids;
extern struct btf_id_set8 scx_kfunc_ids_cid;
void scx_cmask_clear(struct scx_cmask *m);
void scx_cmask_fill(struct scx_cmask *m);

9
kernel/sched/ext/ext.c
View File

@@ -10866,19 +10866,20 @@ int scx_kfunc_context_filter(const struct bpf_prog *prog, u32 kfunc_id)
bool in_idle = btf_id_set8_contains(&scx_kfunc_ids_idle, 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);
u32 moff, flags;
/* Not an SCX kfunc - allow. */
if (!(in_unlocked || in_init_cids || in_select_cpu || in_enqueue || in_dispatch ||
in_cpu_release || in_idle || in_any))
in_cpu_release || in_idle || in_any || in_cid))
return 0;
/* SYSCALL progs (e.g. BPF test_run()) may call unlocked and select_cpu kfuncs. */
if (prog->type == BPF_PROG_TYPE_SYSCALL)
return (in_unlocked || in_select_cpu || in_idle || in_any) ? 0 : -EACCES;
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) ? 0 : -EACCES;
return (in_any || in_idle || in_cid) ? 0 : -EACCES;
/*
* add_subprog_and_kfunc() collects all kfunc calls, including dead code
@@ -10913,7 +10914,7 @@ int scx_kfunc_context_filter(const struct bpf_prog *prog, u32 kfunc_id)
return -EACCES;
/* SCX struct_ops: check the per-op allow list. */
if (in_any || in_idle)
if (in_any || in_idle || in_cid)
return 0;
moff = prog->aux->attach_st_ops_member_off;