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 Unfortunately, devcoredump is a bit lacking in documentation. Arend was writing a bit for the new trigger mechanism at least. Brian
