Hi

On Fri, Oct 10, 2014 at 3:45 PM, Tom Gundersen [off-list ref] wrote:

On Fri, Oct 10, 2014 at 11:54 PM, Anatol Pomozov
[off-list ref] wrote:

quoted

1) Why not to make the timeout configurable through config file? There
is already udev.conf you can put config option there. Thus people with
modprobe issues can easily "fix" the problem. And then decrease
default timeout back to 30 seconds. I agree that long module loading
(more than 30 secs) is abnormal and should be investigated by driver
authors.

We can already configure this either on the udev or kernel
commandline, is that not sufficient (I don't object to also adding it
to the config file, just asking)?

I did not know that udev timeout can be configured via kernel cmd. And
because other people ask about changing timeout they most like did not
know about it neither. Actually looking at
http://www.freedesktop.org/software/systemd/man/kernel-command-line.html
I do not see where it mentions udev timeout.

I think adding configuration to the right place (udev config file) and
adding documentation to make the option more discoverable will solve
the topic starter issue. Now anyone can easily set timeout they want.
The default timeout can go back to 30 sec in this case.

quoted

2) Could you add 'echo w > /proc/sysrq-trigger' to udev code right
before killing the "modprobe" thread? sysrq will print information
about stuck threads (including modprobe itself) this will make
debugging easier. e.g. dmesg here
https://bugs.archlinux.org/task/40454 says nothing where the threads
were stuck.

Are the current warnings (in udev git) sufficient (should tell you
which module is taking long, but still won't tell you which kernel
thread of course)?

True. module name should be enough. In this case to debug the issue user needs:
 - disable failing udev rule (or blacklist module?)
 - reboot, it will let the user get into shell
 - modprobe the failing module
 - use sysrq-trigger to get more information about stuck process

So it is more matter of easier problem debugging. Not critical but it
will be useful imho. This feature can be configured via udev.conf