Commit bf7a6a67 authored by Vincent Li's avatar Vincent Li Committed by Daniel Borkmann
Browse files

bpftool: Add kernel.kptr_restrict hint for no instructions 



From bpftool's github repository issue [0]: When a Linux distribution
has the kernel.kptr_restrict set to 2, bpftool prog dump jited returns
"no instructions returned". This message can be puzzling to bpftool
users who are not familiar with kernel BPF internals, so add a small
hint for bpftool users to check the kernel.kptr_restrict setting
similar to the DUMP_XLATED case. Outside of kernel.kptr_restrict, no
instructions could also be returned in case the JIT was disabled.

Signed-off-by: default avatarVincent Li <vincent.mc.li@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://github.com/libbpf/bpftool/issues/184 [0]
Link: https://lore.kernel.org/bpf/20250818165113.15982-1-vincent.mc.li@gmail.com
parent 5c42715e

tools/bpf/bpftool/prog.c

+1 −1
Original line number Diff line number Diff line
@@ -714,7 +714,7 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode, 


	if (mode == DUMP_JITED) {

		if (info->jited_prog_len == 0 || !info->jited_prog_insns) {

			p_info("no instructions returned");

			p_err("error retrieving jit dump: no instructions returned or kernel.kptr_restrict set?");

			return -1;

		}

		buf = u64_to_ptr(info->jited_prog_insns);