Re: udev blkid check on mmcblk0boot0 and boot1

[Lennart Poettering <lennart@xxxxxxxxxxxxxx>]

On Di, 02.02.21 11:46, Alan Perry (alanp@xxxxxxxxxxxxx) wrote:

>
> On 2/2/21 1:55 AM, Lennart Poettering wrote:
> > On Mo, 01.02.21 16:36, Alan Perry (alanp@xxxxxxxxxxxxx) wrote:
> > > Hi, Per the udev rules, the blkid builtin is run on mmcblk*boot*
> > > devices to look for partition and filesystem. Those devices contain
> > > hardware-specific boot information and are unlikely to have anything
> > > on them that blkid would identify. Why isn't there a rule to exclude
> > > them from blkid? Is there some case that I am missing?
> > Probably noone who cares about MMC enough prepped a patch for this so
> > far. Also it probably doesn't matter too much... I mean, if blkid
> > doesn't find anything it doesn't find anything, so not much bad
> > happened? If this matters to you, and it's really clear that there is
> > unlikely anything blkid-recognizable on it, then by all means, please
> > send a PR!
>
> I have been looking into a problem that we occasionally see with hangs at
> boot time during the probe of
> mmcblk0boot0. Doing some searching, I have seen reports of similar hangs
> over the years, so I see a
> potential benefit of not doing the probe.
>
> Is the blkid/libblkid code robust enough that it could sanely handle
> whatever hardware-specific collection of bits representing the boot
> configuration that happens to be there?

Well, the idea is that blkid tries to recognize what it can recognize
and is careful enough to not be fooled too easily. So far we didn't
really have any reports that media was rubbish on it was misdetected somehow.

Lennart

--
Lennart Poettering, Berlin
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