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 12/18] bpf: Reject stack arguments if tail call reachable
Date: Sat, 11 Apr 2026 22:00:10 -0700 [thread overview]
Message-ID: <20260412050010.266625-1-yonghong.song@linux.dev> (raw)
In-Reply-To: <20260412045826.254200-1-yonghong.song@linux.dev>
Tailcalls are been deprecated. So reject stack arguments
if tail call is in the way.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
kernel/bpf/verifier.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 20fb53ead728..45987041bb2a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7175,6 +7175,11 @@ static int check_max_stack_depth_subprog(struct bpf_verifier_env *env, int idx,
verbose(env, "cannot tail call within exception cb\n");
return -EINVAL;
}
+ if (subprog[tmp].incoming_stack_arg_depth ||
+ subprog[tmp].outgoing_stack_arg_depth) {
+ verbose(env, "tail_calls are not allowed in programs with stack args\n");
+ return -EINVAL;
+ }
subprog[tmp].tail_call_reachable = true;
}
if (subprog[0].tail_call_reachable)
--
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 ` [PATCH bpf-next v4 11/18] bpf: Reject stack arguments in non-JITed programs Yonghong Song
2026-04-12 5:00 ` Yonghong Song [this message]
2026-04-12 5:43 ` [PATCH bpf-next v4 12/18] bpf: Reject stack arguments if tail call reachable 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=20260412050010.266625-1-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