From: Eduard Zingerman <eddyz87@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>, bpf@vger.kernel.org
Cc: daniel@iogearbox.net, andrii@kernel.org, memxor@gmail.com
Subject: Re: [PATCH bpf-next v2 06/17] bpf: Add callx calls to the call graph
Date: Wed, 23 Sep 2026 22:00:51 -0700 [thread overview]
Message-ID: <bad0996bd4b9850e2889c2fc09ca102e0bb24ffd.camel@gmail.com> (raw)
In-Reply-To: <20260924031042.1690890-7-alexei.starovoitov@gmail.com>
On Thu, 2026-09-24 at 03:10 +0000, Alexei Starovoitov wrote:
...
> /*
> * Sort subprogs in topological order so that leaf subprogs come first and
> * their callers come later. This is a DFS post-order traversal of the call
> * graph. Scan only reachable instructions (those in the computed postorder) of
> * the current subprog to discover callees (direct subprogs and sync
> * callbacks).
> + *
> + * The callees of callx are not known before the main verification pass.
> + * When callx is used the sort is repeated after it with the recorded callx
> + * edges added to the call graph to reject recursion through indirect calls.
> */
> static int sort_subprogs_topo(struct bpf_verifier_env *env)
> {
Changes to sort_subprogs_topo() and the second sort call are unnecessary.
After changes to check_max_stack_depth_subprog() in patch #1 of this
series the recursion will be detected there.
...
> @@ -21978,6 +22069,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr,
> ret = do_check_main(env);
> ret = ret ?: do_check_subprogs(env);
>
> + /* reject recursion through the callx edges found by the main pass */
> + if (ret == 0 && env->callx_edges)
> + ret = sort_subprogs_topo(env);
> +
> if (ret == 0 && bpf_prog_is_offloaded(env->prog->aux))
> ret = bpf_prog_offload_finalize(env);
next prev parent reply other threads:[~2026-09-24 5:00 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-24 3:10 [PATCH bpf-next v2 00/17] bpf: Indirect calls of bpf subprogs (callx) Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 01/17] bpf: Fix infinite loop in check_max_stack_depth() Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 02/17] selftests/bpf: Test recursion through a global function and a callback Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 03/17] bpf: Keep functions with address taken when removing dead code Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 04/17] bpf: Prepare static analysis passes for callx instruction Alexei Starovoitov
2026-09-24 3:56 ` bot+bpf-ci
2026-09-24 4:18 ` Eduard Zingerman
2026-09-24 3:10 ` [PATCH bpf-next v2 05/17] bpf: Add callx instruction to call bpf subprogs indirectly Alexei Starovoitov
2026-09-24 3:28 ` sashiko-bot
2026-09-24 3:10 ` [PATCH bpf-next v2 06/17] bpf: Add callx calls to the call graph Alexei Starovoitov
2026-09-24 3:26 ` sashiko-bot
2026-09-24 3:56 ` bot+bpf-ci
2026-09-24 5:00 ` Eduard Zingerman [this message]
2026-09-24 3:10 ` [PATCH bpf-next v2 07/17] bpf, x86: Add JIT support for callx Alexei Starovoitov
2026-09-24 5:33 ` Eduard Zingerman
2026-09-24 3:10 ` [PATCH bpf-next v2 08/17] bpf, arm64: " Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 09/17] bpf: Discover subprogs described by func_info Alexei Starovoitov
2026-09-24 5:42 ` Eduard Zingerman
2026-09-24 3:10 ` [PATCH bpf-next v2 10/17] bpf: Recognize pointers to functions in read-only maps Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 11/17] libbpf: Support pointers to static functions in data when linking Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 12/17] libbpf: Resolve pointers to functions in read-only data Alexei Starovoitov
2026-09-24 3:27 ` sashiko-bot
2026-09-24 3:10 ` [PATCH bpf-next v2 13/17] libbpf: Treat .data.rel.ro as " Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 14/17] libbpf: Support pointers to functions in read-only data in light skeleton Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 15/17] selftests/bpf: Add tests for callx Alexei Starovoitov
2026-09-24 3:56 ` bot+bpf-ci
2026-09-24 3:10 ` [PATCH bpf-next v2 16/17] selftests/bpf: Add tests for callx through pointers in read-only data Alexei Starovoitov
2026-09-24 3:10 ` [PATCH bpf-next v2 17/17] bpf, docs: Document callx instruction Alexei Starovoitov
2026-09-24 5:50 ` [PATCH bpf-next v2 00/17] bpf: Indirect calls of bpf subprogs (callx) patchwork-bot+netdevbpf
2026-09-24 5:55 ` Eduard Zingerman
2026-09-24 6:00 ` Alexei Starovoitov
2026-09-24 17:50 ` Ihor Solodrai
2026-09-24 18:09 ` Alexei Starovoitov
2026-09-28 23:13 ` Ihor Solodrai
2026-09-29 6:04 ` Alexei Starovoitov
2026-09-29 16:40 ` Ihor Solodrai
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=bad0996bd4b9850e2889c2fc09ca102e0bb24ffd.camel@gmail.com \
--to=eddyz87@gmail.com \
--cc=alexei.starovoitov@gmail.com \
--cc=andrii@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=memxor@gmail.com \
/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