From: Yonghong Song <yonghong.song@linux.dev>
To: bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"Jose E . Marchesi" <jose.marchesi@oracle.com>,
kernel-team@fb.com, Martin KaFai Lau <martin.lau@kernel.org>
Subject: [PATCH bpf-next v4 11/18] bpf: Reject stack arguments in non-JITed programs
Date: Sat, 11 Apr 2026 22:00:05 -0700 [thread overview]
Message-ID: <20260412050005.264809-1-yonghong.song@linux.dev> (raw)
In-Reply-To: <20260412045826.254200-1-yonghong.song@linux.dev>
The interpreter does not understand the bpf register r12
(BPF_REG_STACK_ARG_BASE) used for stack argument addressing. So
reject interpreter usage if stack arguments are used either
in the main program or any subprogram.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
kernel/bpf/core.c | 3 ++-
kernel/bpf/verifier.c | 6 ++++++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 76a4e208f34e..1bd8a19d7b61 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2555,7 +2555,8 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
goto finalize;
if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) ||
- bpf_prog_has_kfunc_call(fp))
+ bpf_prog_has_kfunc_call(fp) ||
+ fp->aux->stack_arg_depth)
jit_needed = true;
if (!bpf_prog_select_interpreter(fp))
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bfeecd73e66e..20fb53ead728 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -24030,6 +24030,12 @@ static int fixup_call_args(struct bpf_verifier_env *env)
verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
return -EINVAL;
}
+ for (i = 0; i < env->subprog_cnt; i++) {
+ if (env->subprog_info[i].incoming_stack_arg_depth) {
+ verbose(env, "stack args are not supported in non-JITed programs\n");
+ return -EINVAL;
+ }
+ }
if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
/* When JIT fails the progs with bpf2bpf calls and tail_calls
* have to be rejected, since interpreter doesn't support them yet.
--
2.52.0
next prev parent reply other threads:[~2026-04-12 5:00 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-12 4:58 [PATCH bpf-next v4 00/18] bpf: Support stack arguments for BPF functions and kfuncs Yonghong Song
2026-04-12 4:58 ` [PATCH bpf-next v4 01/18] bpf: Remove unused parameter from check_map_kptr_access() Yonghong Song
2026-04-12 4:58 ` [PATCH bpf-next v4 02/18] bpf: Change from "arg #%d" to "arg#%d" in verifier log Yonghong Song
2026-04-12 4:58 ` [PATCH bpf-next v4 03/18] bpf: Refactor to avoid redundant calculation of bpf_reg_state Yonghong Song
2026-04-12 5:31 ` bot+bpf-ci
2026-04-12 4:58 ` [PATCH bpf-next v4 04/18] bpf: Refactor to handle memory and size together Yonghong Song
2026-04-12 5:31 ` bot+bpf-ci
2026-04-12 4:58 ` [PATCH bpf-next v4 05/18] bpf: Change some regno type from u32 to int type Yonghong Song
2026-04-12 4:58 ` [PATCH bpf-next v4 06/18] bpf: Use argument index instead of register index in kfunc verifier logs Yonghong Song
2026-04-12 5:43 ` bot+bpf-ci
2026-04-12 4:59 ` [PATCH bpf-next v4 07/18] bpf: Introduce bpf register BPF_REG_STACK_ARG_BASE Yonghong Song
2026-04-12 4:59 ` [PATCH bpf-next v4 08/18] bpf: Reuse MAX_BPF_FUNC_ARGS for maximum number of arguments Yonghong Song
2026-04-12 4:59 ` [PATCH bpf-next v4 09/18] bpf: Support stack arguments for bpf functions Yonghong Song
2026-04-12 5:43 ` bot+bpf-ci
2026-04-12 5:00 ` [PATCH bpf-next v4 10/18] bpf: Fix interaction between stack argument PTR_TO_STACK and dead slot poisoning Yonghong Song
2026-04-12 5:43 ` bot+bpf-ci
2026-04-12 5:00 ` Yonghong Song [this message]
2026-04-12 5:00 ` [PATCH bpf-next v4 12/18] bpf: Reject stack arguments if tail call reachable Yonghong Song
2026-04-12 5:43 ` bot+bpf-ci
2026-04-12 5:00 ` [PATCH bpf-next v4 13/18] bpf: Support stack arguments for kfunc calls Yonghong Song
2026-04-12 5:43 ` bot+bpf-ci
2026-04-12 5:00 ` [PATCH bpf-next v4 14/18] bpf: Enable stack argument support for x86_64 Yonghong Song
2026-04-12 5:00 ` [PATCH bpf-next v4 15/18] bpf,x86: Implement JIT support for stack arguments Yonghong Song
2026-04-12 5:43 ` bot+bpf-ci
2026-04-12 5:00 ` [PATCH bpf-next v4 16/18] selftests/bpf: Add tests for BPF function " Yonghong Song
2026-04-12 5:00 ` [PATCH bpf-next v4 17/18] selftests/bpf: Add negative test for greater-than-8-byte kfunc stack argument Yonghong Song
2026-04-12 5:00 ` [PATCH bpf-next v4 18/18] selftests/bpf: Add verifier tests for stack argument validation Yonghong Song
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260412050005.264809-1-yonghong.song@linux.dev \
--to=yonghong.song@linux.dev \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=jose.marchesi@oracle.com \
--cc=kernel-team@fb.com \
--cc=martin.lau@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox