Commit 9360dfe4 authored by Andrea Righi's avatar Andrea Righi Committed by Tejun Heo
Browse files

sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl() 



If a BPF scheduler provides an invalid CPU (outside the nr_cpu_ids
range) as prev_cpu to scx_bpf_select_cpu_dfl() it can cause a kernel
crash.

To prevent this, validate prev_cpu in scx_bpf_select_cpu_dfl() and
trigger an scx error if an invalid CPU is specified.

Fixes: f0e1a064 ("sched_ext: Implement BPF extensible scheduler class")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: default avatarAndrea Righi <arighi@nvidia.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 8fef0a3b

kernel/sched/ext.c

+3 −0
Original line number Diff line number Diff line
@@ -6422,6 +6422,9 @@ static bool check_builtin_idle_enabled(void) 
__bpf_kfunc s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu,

				       u64 wake_flags, bool *is_idle)

{

	if (!ops_cpu_valid(prev_cpu, NULL))

		goto prev_cpu;



	if (!check_builtin_idle_enabled())

		goto prev_cpu;