On (12/04/18 19:16), Tetsuo Handa wrote:
> On 2018/12/04 11:02, Sergey Senozhatsky wrote:
> > On (12/02/18 20:23), Tetsuo Handa wrote:
> >>
> >> Some examples for console output:
> >>
> >> [ 0.919699]@T1 x86: Booting SMP configuration:
> >> [ 4.152681]@T271 Fusion MPT base driver 3.04.20
> >> [ 5.070470]@C0 random: fast init done
> >> [ 6.587900]@C3 random: crng init done
> >
> > This is hard to read. Let's have a fixed width space for from_id.
>
> Console might be only 80 columns. When we have to check from screen capture of
> crash, triggering needless newlines due to occupying columns more than needed
> will not be nice. Also, syzbot has file size limit for saving console output.
> Wasting with needless spaces increases possibility of loosing past lines.
> Given that said, do you still want to waste precious columns with spaces?
Well, if the feature will be useful for non-syzbot cases as well, as
you mention below, then I'd say let's make the output human readable.
To some extent, at least.
I think we consume much more bytes on pr_fmt prefixes; and not all of them
are very useful all the time.
[..]
[ 1.223872] nouveau 0000:01:00.0: DRM: DCB outp 00: 01000f02 00020030
[ 1.224090] nouveau 0000:01:00.0: DRM: DCB outp 01: 02011f62 00020010
[..]
[ 2.676030] snd_hda_codec_realtek hdaudioC0D0: autoconfig for ALC662 rev3:
line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:line
[ 2.676643] snd_hda_codec_realtek hdaudioC0D0: speaker_outs=0
(0x0/0x0/0x0/0x0/0x0)
[ 2.677258] snd_hda_codec_realtek hdaudioC0D0: hp_outs=1
(0x1b/0x0/0x0/0x0/0x0)
[ 2.677879] snd_hda_codec_realtek hdaudioC0D0: mono: mono_out=0x0
[ 2.678578] snd_hda_codec_realtek hdaudioC0D0: inputs:
[ 2.679150] snd_hda_codec_realtek hdaudioC0D0: Front Mic=0x19
[..]
[ 430.768498] rndis_host 1-1:1.0 enp0s20f0u1: unregister 'rndis_host'
usb-0000:00:14.0-1, RNDIS device
So, to me, PRINTK_FROM probably does not look like a really bad
serial console abuser. How many bytes do we need for PRINTK_FROM?
7-8?
> CONFIG_DEBUG_AID_FOR_SYZBOT is currently linux-next only option.
> This feature will be useful for non-syzbot environments.
-ss
