On 2/25/25 12:17 PM, Breno Leitao wrote:
> On Tue, Feb 25, 2025 at 10:19:10AM +0000, Simon Horman wrote:
>> On Fri, Feb 21, 2025 at 05:52:10AM -0800, Breno Leitao wrote:
>>> This is the core patch for this whole patchset. Add support for
>>> including the current task's name in netconsole's extra data output.
>>> This adds a new append_taskname() function that writes the task name
>>> (from current->comm) into the target's extradata buffer, similar to how
>>> CPU numbers are handled.
>>>
>>> The task name is included when the SYSDATA_TASKNAME field is set,
>>> appearing in the format "taskname=<name>" in the output. This additional
>>> context can help with debugging by showing which task generated each
>>> console message.
>>>
>>> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
>>> ---
>>> drivers/net/netconsole.c | 14 +++++++++++++-
>>> 1 file changed, 13 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
>>> index 5a29144ae37ee7b487b1a252b0f2ce8574f9cefa..625f4c0be11d8deb454139b1c526abc842697219 100644
>>> --- a/drivers/net/netconsole.c
>>> +++ b/drivers/net/netconsole.c
>>> @@ -1179,12 +1179,22 @@ static int append_cpu_nr(struct netconsole_target *nt, int offset)
>>> raw_smp_processor_id());
>>> }
>>>
>>> +static int append_taskname(struct netconsole_target *nt, int offset)
>>> +{
>>> + if (WARN_ON_ONCE(!current))
>>> + return 0;
>>
>> Hi Breno,
>>
>> I gather that theoretically this could occur, but it isn't expected
>> to happen in practice. Is that right?
>
> That's correct. `current` isn't expected to be NULL in practice.
> I've been running this code on several servers for days and have never
> encountered this warning.
>
> While the taskname feature isn't enabled during early boot, netconsole
> might be active at that time, which is why I exercised extra caution
> here.
So `current` can't be NULL here. I think it's better to drop such check,
it's presence would be misleading. i.e. like adding checks for UDP stack
being initialized before calling send_msg_fragmented()
Cheers,
Paolo
