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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>,
	kernel-team@fb.com, Martin KaFai Lau <martin.lau@kernel.org>
Subject: [PATCH bpf-next 1/2] bpf: Remove a WARN_ON_ONCE warning related to local kptr
Date: Wed, 23 Aug 2023 15:55:56 -0700	[thread overview]
Message-ID: <20230823225556.1292811-1-yonghong.song@linux.dev> (raw)

Currently, in function bpf_obj_free_fields(), for local kptr,
a warning will be issued if the struct does not contain any
special fields. But actually the kernel seems totally okay
with a local kptr without any special fields. Permitting
no special fields also aligns with future percpu kptr which
also allows no special fields.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 kernel/bpf/syscall.c | 1 -
 1 file changed, 1 deletion(-)

NOTE: I didn't put a fix tag since except the warning
there is no correctness issue here.

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 10666d17b9e3..ebeb0695305a 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -657,7 +657,6 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj)
 			if (!btf_is_kernel(field->kptr.btf)) {
 				pointee_struct_meta = btf_find_struct_meta(field->kptr.btf,
 									   field->kptr.btf_id);
-				WARN_ON_ONCE(!pointee_struct_meta);
 				migrate_disable();
 				__bpf_obj_drop_impl(xchgd_field, pointee_struct_meta ?
 								 pointee_struct_meta->record :
-- 
2.34.1


             reply	other threads:[~2023-08-23 22:56 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-23 22:55 Yonghong Song [this message]
2023-08-23 22:56 ` [PATCH bpf-next 2/2] selftests/bpf: Add a local kptr test with no special fields Yonghong Song
2023-08-24  5:31   ` David Marchevsky
2023-08-24  5:56     ` Yonghong Song
2023-08-24  5:16 ` [PATCH bpf-next 1/2] bpf: Remove a WARN_ON_ONCE warning related to local kptr David Marchevsky

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