In the Linux kernel, the following vulnerability has been resolved:
bpf: Check rcureadlocktraceheld() in bpfmaplookuppercpuelem()
bpfmaplookuppercpuelem() helper is also available for sleepable bpf program. When BPF JIT is disabled or under 32-bit host, bpfmaplookuppercpuelem() will not be inlined. Using it in a sleepable bpf program will trigger the warning in bpfmaplookuppercpuelem(), because the bpf program only holds rcureadlock_trace lock. Therefore, add the missed check.