On 06/05/2018 03:53 PM, Brian Norris wrote:
Hi,
On Tue, Jun 05, 2018 at 03:27:28PM -0700, Ben Greear wrote:
I have been testing ath10k on 4.16, which uses the devcoredump API
to notify about dumps.
I am able to see the binary crash dump at /sys/class/devcoredump/devcd2/data,
for instance, but if I do another crash quickly, I get no new uevent sent
and no new crash.
I see there is a 5 minute timer on the coredump data, but it also seems to indicate
that if I read the crash, the data should be cleared and ready to be
recreated again? How do you notify the system that the crash data has
been read?
I tried 'cat' on the data file, but that did not seem to clear anything.
Try *writing* to it?
https://elixir.bootlin.com/linux/v4.16/source/drivers/base/devcoredump.c#L91
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=833c95456a70826d1384883b73fd23aff24d366f
<quote>
The dumped data will be readable in sysfs in the virtual device's
data file under /sys/class/devcoredump/devcd*/. Writing to it will
free the data and remove the device, as does a 5-minute timeout.
</quote>
e.g.:
# ls -l /sys/class/devcoredump/devcd1
lrwxrwxrwx. 1 root root 0 Jun 5 15:49 /sys/class/devcoredump/devcd1 -> ../../devices/virtual/devcoredump/devcd1
# echo 1 > /sys/class/devcoredump/devcd1/data
# ls -l /sys/class/devcoredump/devcd1
ls: cannot access '/sys/class/devcoredump/devcd1': No such file or directory
Thanks to all who responded. That indeed works just fine.
Just in case you know a quick answer: I opened a netlink socket to listen
to uevents so I would know when FW crashed. It receives the kernel messages,
but also receives 'libudev' events which seem to have some binary header in
them (which I could not google any info about how to decode it). Is there
an easy way to tell the socket to not send the libudev events?
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
