Re: [PATCH v9 tip 6/9] samples: bpf: simple non-portable kprobe filter example

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 3/23/15 12:29 AM, Ingo Molnar wrote:

**                                                      **
** This means that this is a DEBUG kernel and it is     **
** unsafe for production use.                           **

But I think printing that it's unsafe for production use is over the
top: it's up to the admin whether it's safe or unsafe, just like
inserting a kprobe can be safe or unsafe.

Informing that something happened is enough.

Well that is Steven's banner and I agree that it's a bit extreme.
I think it's done on purpose to scary people away from using
trace_printk() for anything other than debug.
It applies to both native trace_printk() for kernel debugging and
for bpf_trace_printk() for debugging of bpf programs.
I don't have a strong opinion about native case, but for bpf I do want
this banner to be scary. Otherwise it's too easy to start using
bpf_trace_printk() to pass event notifications to user space.
bpf_trace_printk and trace_pipe parsing shouldn't be used as a way
to communicate between programs and user space.
At the end, in actual production use, bpf programs won't be using it
and no banner will be seen.
Anyway, I don't think I can change this banner in this patch set.
If we decide to relax it, it should be done via Steven's tree.
--
To unsubscribe from this list: send the line "unsubscribe linux-api" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux