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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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: Vincent Li <vincent.mc.li@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel 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

authored by

Vincent Li and committed by
Daniel Borkmann bf7a6a67 5c42715e

+1 -1
+1 -1
tools/bpf/bpftool/prog.c
··· 714 714 715 715 if (mode == DUMP_JITED) { 716 716 if (info->jited_prog_len == 0 || !info->jited_prog_insns) { 717 - p_info("no instructions returned"); 717 + p_err("error retrieving jit dump: no instructions returned or kernel.kptr_restrict set?"); 718 718 return -1; 719 719 } 720 720 buf = u64_to_ptr(info->jited_prog_insns);