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bpf: Disallow interpreter fallback for arena-related insns

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Since the interpreter does not support the arena-related insns,
interpreter fallback should not be allowed for these insns in
core.c::__bpf_prog_select_runtime().

Currently, when the interpreter executes the arena ST/LDX/STX insns,
it would hit the BUG_ON() in ___bpf_prog_run() at run time.

[    2.579196] BPF interpreter: unknown opcode a2 (imm: 0x0)
[    2.579998] ------------[ cut here ]------------
[    2.580652] kernel BUG at kernel/bpf/core.c:2349!
[    2.581314] Oops: invalid opcode: 0000 [#1] SMP PTI

Set jit_required as true when arena map is used in the prog to disallow
interpreter fallback for arena-related insns.

Fixes: 6082b6c328 ("bpf: Recognize addr_space_cast instruction in the verifier.")
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/bpf/20260715141122.15783-2-leon.hwang@linux.dev
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
This commit is contained in:
Leon Hwang
2026-07-15 22:11:20 +08:00
committed by Kumar Kartikeya Dwivedi
parent deabfadbb2
commit 34746b5a84
1 changed files with 1 additions and 0 deletions
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kernel/bpf/verifier.c
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@@ -17887,6 +17887,7 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
return -EOPNOTSUPP;
}
env->prog->aux->arena = (void *)map;
env->prog->jit_required = true;
if (!bpf_arena_get_user_vm_start(env->prog->aux->arena)) {
verbose(env, "arena's user address must be set via map_extra or mmap()\n");
return -EINVAL;