Re: [PATCH linux-next] bpf: fix warning for crash_kexec

From: Yonghong Song <yonghong.song@linux.dev>
To: Hari Bathini <hbathini@linux.ibm.com>, bpf@vger.kernel.org
Cc: Kexec-ml <kexec@lists.infradead.org>, Baoquan He <bhe@redhat.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH linux-next] bpf: fix warning for crash_kexec
Date: Mon, 18 Mar 2024 09:13:11 -0700	[thread overview]
Message-ID: <4bcdd9cc-6149-490e-b3df-a39346e5035b@linux.dev> (raw)
In-Reply-To: <6a1d94f7-b4bf-4315-b862-4e278abbaa73@linux.ibm.com>

On 3/17/24 11:52 PM, Hari Bathini wrote:
> Just checking on whether this will go via bpf or mm tree?

Sending to bpf-next should be okay.
Could you resubmit the patch as CONFIG_CRASH_DUMP probably not
available to bpf-next when you initially submitted the patch.

>
> On 09/02/24 6:05 pm, Hari Bathini wrote:
>> With [1], CONFIG_KEXEC & !CONFIG_CRASH_DUMP is supported but that led
>> to the below warning:
>>
>>    "WARN: resolve_btfids: unresolved symbol crash_kexec"
>>
>> Fix it by using the appropriate #ifdef.
>>
>> [1] https://lore.kernel.org/all/20240124051254.67105-1-bhe@redhat.com/
>>
>> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
>> ---
>>   kernel/bpf/helpers.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
>> index 4db1c658254c..e408d1115e26 100644
>> --- a/kernel/bpf/helpers.c
>> +++ b/kernel/bpf/helpers.c
>> @@ -2545,7 +2545,7 @@ __bpf_kfunc void bpf_throw(u64 cookie)
>>   __bpf_kfunc_end_defs();
>>     BTF_KFUNCS_START(generic_btf_ids)
>> -#ifdef CONFIG_KEXEC_CORE
>> +#ifdef CONFIG_CRASH_DUMP
>>   BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
>>   #endif
>>   BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
>