On Saturday, March 03/24/18, 2018 at 20:50:52 +0530, Eric W. Biederman wrote: > > Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx> writes: > > > On production servers running variety of workloads over time, kernel > > panic can happen sporadically after days or even months. It is > > important to collect as much debug logs as possible to root cause > > and fix the problem, that may not be easy to reproduce. Snapshot of > > underlying hardware/firmware state (like register dump, firmware > > logs, adapter memory, etc.), at the time of kernel panic will be very > > helpful while debugging the culprit device driver. > > > > This series of patches add new generic framework that enable device > > drivers to collect device specific snapshot of the hardware/firmware > > state of the underlying device in the crash recovery kernel. In crash > > recovery kernel, the collected logs are exposed via /sys/kernel/crashdd/ > > directory, which is copied by user space scripts for post-analysis. > > > > A kernel module crashdd is newly added. In crash recovery kernel, > > crashdd exposes /sys/kernel/crashdd/ directory containing device > > specific hardware/firmware logs. > > Have you looked at instead of adding a sysfs file adding the dumps > as additional elf notes in /proc/vmcore? > I see the crash recovery kernel's memory is not present in any of the the PT_LOAD headers. So, makedumpfile is not collecting the dumps that are in crash recovery kernel's memory. Also, are you suggesting exporting the dumps themselves as PT_NOTE instead? I'll look into doing it this way. > That should allow existing tools to capture your extended dump > information with no code changes, and it will allow having a single file > core dump for storing the information. > > Both of which should mean something that will integrate better into > existing flows. > > The interface logic of the driver should be essentially the same. > > > Also have you tested this and seen how well your current logic captures > the device information? > Yes, the hardware snapshot is pretty close to the state during kernel panic. It is better than risking not being able to collect anything at all during kernel panic. Thanks, Rahul
