bpf: Check rcu_read_lock_trace_held() before calling bpf map helpers

In the Linux kernel, the following vulnerability has been resolved:

bpf: Check rcu_read_lock_trace_held() before calling bpf map helpers

These three bpf_map_{lookup,update,delete}_elem() helpers are also

available for sleepable bpf program, so add the corresponding lock

assertion for sleepable bpf program, otherwise the following warning

will be reported when a sleepable bpf program manipulates bpf map under

interpreter mode (aka bpf_jit_enable=0):

WARNING: CPU: 3 PID: 4985 at kernel/bpf/helpers.c:40 ......

CPU: 3 PID: 4985 Comm: test_progs Not tainted 6.6.0+ #2

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......

RIP: 0010:bpf_map_lookup_elem+0x54/0x60

......

Call Trace:

<TASK>

? __warn+0xa5/0x240

? bpf_map_lookup_elem+0x54/0x60

? report_bug+0x1ba/0x1f0

? handle_bug+0x40/0x80

? exc_invalid_op+0x18/0x50

? asm_exc_invalid_op+0x1b/0x20

? __pfx_bpf_map_lookup_elem+0x10/0x10

? rcu_lockdep_current_cpu_online+0x65/0xb0

? rcu_is_watching+0x23/0x50

? bpf_map_lookup_elem+0x54/0x60

? __pfx_bpf_map_lookup_elem+0x10/0x10

___bpf_prog_run+0x513/0x3b70

__bpf_prog_run32+0x9d/0xd0

? __bpf_prog_enter_sleepable_recur+0xad/0x120

? __bpf_prog_enter_sleepable_recur+0x3e/0x120

bpf_trampoline_6442580665+0x4d/0x1000

__x64_sys_getpgid+0x5/0x30

? do_syscall_64+0x36/0xb0

entry_SYSCALL_64_after_hwframe+0x6e/0x76

</TASK>