From: Chen Hu <hu1.chen@intel.com>
To: unlisted-recipients:; (no To-header on input)
Cc: hu1.chen@intel.com, jpoimboe@kernel.org, memxor@gmail.com,
bpf@vger.kernel.org, Pengfei Xu <pengfei.xu@intel.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH bpf] selftests/bpf: Fix "missing ENDBR" BUG for destructor kfunc
Date: Mon, 21 Nov 2022 00:51:13 -0800 [thread overview]
Message-ID: <20221121085113.611504-1-hu1.chen@intel.com> (raw)
With CONFIG_X86_KERNEL_IBT enabled, the test_verifier triggers the
following BUG:
traps: Missing ENDBR: bpf_kfunc_call_test_release+0x0/0x30
------------[ cut here ]------------
kernel BUG at arch/x86/kernel/traps.c:254!
invalid opcode: 0000 [#1] PREEMPT SMP
<TASK>
asm_exc_control_protection+0x26/0x50
RIP: 0010:bpf_kfunc_call_test_release+0x0/0x30
Code: 00 48 c7 c7 18 f2 e1 b4 e8 0d ca 8c ff 48 c7 c0 00 f2 e1 b4 c3
0f 1f 44 00 00 66 0f 1f 00 0f 1f 44 00 00 0f 0b 31 c0 c3 66 90
<66> 0f 1f 00 0f 1f 44 00 00 48 85 ff 74 13 4c 8d 47 18 b8 ff ff ff
bpf_map_free_kptrs+0x2e/0x70
array_map_free+0x57/0x140
process_one_work+0x194/0x3a0
worker_thread+0x54/0x3a0
? rescuer_thread+0x390/0x390
kthread+0xe9/0x110
? kthread_complete_and_exit+0x20/0x20
This is because there are no compile-time references to the destructor
kfuncs, bpf_kfunc_call_test_release() for example. So objtool marked
them sealable and ENDBR in the functions were sealed (converted to NOP)
by apply_ibt_endbr().
This fix creates dummy compile-time references to destructor kfuncs so
ENDBR stay there.
Signed-off-by: Chen Hu <hu1.chen@intel.com>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
---
include/linux/btf_ids.h | 7 +++++++
net/bpf/test_run.c | 2 ++
2 files changed, 9 insertions(+)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 2aea877d644f..6c6b520ea58f 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -266,4 +266,11 @@ MAX_BTF_TRACING_TYPE,
extern u32 btf_tracing_ids[];
+#if defined(CONFIG_X86_KERNEL_IBT) && !defined(__DISABLE_EXPORTS)
+#define BTF_IBT_NOSEAL(name) \
+ asm(IBT_NOSEAL(#name));
+#else
+#define BTF_IBT_NOSEAL(name)
+#endif /* CONFIG_X86_KERNEL_IBT */
+
#endif
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 13d578ce2a09..465952e5de11 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -1653,6 +1653,8 @@ BTF_ID(struct, prog_test_ref_kfunc)
BTF_ID(func, bpf_kfunc_call_test_release)
BTF_ID(struct, prog_test_member)
BTF_ID(func, bpf_kfunc_call_memb_release)
+BTF_IBT_NOSEAL(bpf_kfunc_call_test_release)
+BTF_IBT_NOSEAL(bpf_kfunc_call_memb_release)
static int __init bpf_prog_test_run_init(void)
{
--
2.34.1
next reply other threads:[~2022-11-21 8:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 8:51 Chen Hu [this message]
2022-11-21 14:32 ` [PATCH bpf] selftests/bpf: Fix "missing ENDBR" BUG for destructor kfunc Jiri Olsa
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