[PATCH bpf-next v4 00/12] bpf: make the vmlinux BTF an on-demand loadable module (CONFIG_DEBUG_INFO_BTF=m) to save ~5.4 MB memory · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 01/12] bpf: pass the vmlinux BTF to btf_parse_module() and let it adopt the data · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 02/12] bpf: split the kfunc, dtor kfunc and struct_ops registration bodies · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 03/12] bpf: fetch the vmlinux BTF where kernel types enter a program · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 04/12] bpf: take the vmlinux BTF from the btf_vmlinux module · Jay Wang <hidden> · 2026-10-01
Re: [PATCH bpf-next v4 04/12] bpf: take the vmlinux BTF from the btf_vmlinux module · bot+bpf-ci@kernel.org · 2026-10-01
[PATCH bpf-next v4 05/12] bpf, tracing: load the vmlinux BTF where tracefs and bpffs requests start · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 06/12] bpf: defer vmlinux kfunc and struct_ops registrations · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 07/12] bpf: keep module BTF until the vmlinux BTF is available · Jay Wang <hidden> · 2026-10-01
Re: [PATCH bpf-next v4 07/12] bpf: keep module BTF until the vmlinux BTF is available · bot+bpf-ci@kernel.org · 2026-10-01
[PATCH bpf-next v4 08/12] bpf: expose deferred .BTF.base module BTF in sysfs from module load · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 09/12] bpf, trace, net: prepare CONFIG_DEBUG_INFO_BTF checks for a tristate · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 10/12] resolve_btfids: add --btf_link to fill in .BTF.link records · Jay Wang <hidden> · 2026-10-01
Re: [PATCH bpf-next v4 10/12] resolve_btfids: add --btf_link to fill in .BTF.link records · bot+bpf-ci@kernel.org · 2026-10-01
[PATCH bpf-next v4 11/12] tools, samples: take the vmlinux BTF from vmlinux.unstripped first · Jay Wang <hidden> · 2026-10-01
[PATCH bpf-next v4 12/12] kbuild, bpf: allow building the vmlinux BTF as a module · Jay Wang <hidden> · 2026-10-01

Re: [PATCH bpf-next v4 07/12] bpf: keep module BTF until the vmlinux BTF is available

From: bot+bpf-ci@kernel.org
Date: 2026-10-01 23:46:01
Also in: bpf, linux-doc, linux-kbuild, linux-kselftest, linux-modules, linux-perf-users, linux-trace-kernel, lkml, rust-for-linux, sched-ext

bpf: keep module BTF until the vmlinux BTF is available

TL;DR: Nits only: in kernel/bpf/btf.c, btf_drop_deferred_vmlinux_regs() could
reuse the new btf_free_deferred_regs() helper, and the module and vmlinux
apply loops look duplicated. No bug.

quoted hunk ↗ jump to hunk

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 96241dc62dc3..4d51fb212218 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c

[ ... ]

quoted hunk ↗ jump to hunk

@@ -10967,6 +11252,16 @@ static void btf_apply_deferred_regs(struct btf *btf, struct list_head *regs)
 	}
 }

+static void btf_free_deferred_regs(struct list_head *regs)
+{
+	struct btf_deferred_reg *reg, *tmp;
+
+	list_for_each_entry_safe(reg, tmp, regs, list) {
+		list_del(&reg->list);
+		btf_free_deferred_reg(reg);
+	}
+}
+

This isn't a bug, but could btf_drop_deferred_vmlinux_regs() call the new
btf_free_deferred_regs(&regs) instead of keeping its own copy of the loop?

The tail of btf_drop_deferred_vmlinux_regs() still open-codes the same
thing on its local list:

    list_for_each_entry_safe(reg, tmp, &regs, list) {
        list_del(&reg->list);
        btf_free_deferred_reg(reg);
    }

The splice / unlock / apply / relock loop in btf_module_apply_regs() is
also the same as the one in btf_apply_deferred_vmlinux_regs(), just with a
different mutex.


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/36938681172

`h`	back out one level
`j`	next message in thread
`k`	previous message in thread
`l`	drill in
`Esc`	close help / fold thread tree
`?`	toggle this help