github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

Merge branch 'bpf-fix-builds-broken-by-fatal-resolve_btfids-warnings'

Browse Source 
Sasha Levin says:

====================
bpf: Fix builds broken by fatal resolve_btfids warnings

Commit 201a454df9 ("resolve_btfids: Fix the --fatal_warnings exit
status") makes resolve_btfids warnings fail the build again with
CONFIG_WERROR=y. That exposed BTF ID references to functions some
configs don't build. KernelCI has been seeing i386
i386_defconfig+kselftest builds fail on linux-next since next-20261015:

  WARN: resolve_btfids: unresolved symbol bpf_arena_reserve_pages
  WARN: resolve_btfids: unresolved symbol bpf_arena_free_pages
  WARN: resolve_btfids: unresolved symbol bpf_arena_alloc_pages
  Failed to generate BTF for vmlinux
  Try to disable CONFIG_DEBUG_INFO_BTF

https://files.kernelci.org/kbuild-gcc-14-i386-kselftest-6ad2315ca3f195e1aa930c8a/build.log.gz

Patch 1 drops three special_kfunc_list entries that have no users,
bpf_arena_reserve_pages among them. Patch 2 makes the remaining arena
entries depend on the condition arena.o is built with. Patch 3 fixes the
same problem for bpf_lsm_socket_sendmsg in bpf_ksock.c, which breaks
x86_64 builds with CONFIG_BPF_LSM=y and CONFIG_SECURITY_NETWORK=n.

The entries left in special_kfunc_list resolve to the same IDs as
before, and the IDs that become BTF_ID_UNUSED were already zero.

Tested by building vmlinux with CONFIG_DEBUG_INFO_BTF=y and
CONFIG_WERROR=y for i386, x86_64, and x86_64 with CONFIG_BPF_LSM=y and
both CONFIG_SECURITY_NETWORK=n and =y, and comparing special_kfunc_list
and bpf_lsm_socket_sendmsg_id before and after the series.
====================

Link: https://patch.msgid.link/20261019211006.2574350-1-sashal@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Alexei Starovoitov 2026-10-20 00:14:28 +00:00
commit b2914fb67f
No known key found for this signature in database
2 changed files with 11 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
kernel/bpf/verifier.c
View File

@ -13612,10 +13612,7 @@ enum special_kfunc_type {
KF_bpf_call_rcu_tasks_trace,
KF_bpf_arena_alloc_pages,
KF_bpf_arena_free_pages,
KF_bpf_arena_reserve_pages,
KF_bpf_session_is_return,
KF_bpf_stream_vprintk,
KF_bpf_stream_print_stack,
};
BTF_ID_LIST(special_kfunc_list)
@ -13705,16 +13702,18 @@ BTF_ID(func, bpf_task_work_schedule_signal)
BTF_ID(func, bpf_task_work_schedule_resume)
BTF_ID(func, bpf_call_rcu)
BTF_ID(func, bpf_call_rcu_tasks_trace)
#if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
BTF_ID(func, bpf_arena_alloc_pages)
BTF_ID(func, bpf_arena_free_pages)
BTF_ID(func, bpf_arena_reserve_pages)
#else
BTF_ID_UNUSED
BTF_ID_UNUSED
#endif
#ifdef CONFIG_BPF_EVENTS
BTF_ID(func, bpf_session_is_return)
#else
BTF_ID_UNUSED
#endif
BTF_ID(func, bpf_stream_vprintk)
BTF_ID(func, bpf_stream_print_stack)
static bool is_bpf_cast_to_kern_ctx_kfunc(const struct bpf_call_arg_meta *meta)
{

7
net/core/bpf_ksock.c
View File

@ -258,7 +258,12 @@ BTF_ID_FLAGS(func, bpf_ksock_send, KF_SLEEPABLE)
BTF_KFUNCS_END(ksock_kfunc_btf_ids)
#ifdef CONFIG_BPF_LSM
BTF_ID_LIST_SINGLE(bpf_lsm_socket_sendmsg_id, func, bpf_lsm_socket_sendmsg)
BTF_ID_LIST(bpf_lsm_socket_sendmsg_id)
#ifdef CONFIG_SECURITY_NETWORK
BTF_ID(func, bpf_lsm_socket_sendmsg)
#else
BTF_ID_UNUSED
#endif
#endif
static int bpf_ksock_kfunc_filter(const struct bpf_prog *prog, u32 kfunc_id)