On Friday, March 03/16/18, 2018 at 16:42:03 +0530, Rahul Lakkireddy wrote: > 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 /proc/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 /proc/crashdd/ directory containing device specific > hardware/firmware logs. > > The sequence of actions done by device drivers to append their device > specific hardware/firmware logs to /proc/crashdd/ directory are as > follows: > > 1. During probe (before hardware is initialized), device drivers > register to the crashdd module (via crashdd_add_dump()), with > callback function, along with buffer size and log name needed for > firmware/hardware log collection. > > 2. Crashdd creates a driver's directory under /proc/crashdd/<driver>. > Then, it allocates the buffer with requested size and invokes the > device driver's registered callback function. > > 3. Device driver collects all hardware/firmware logs into the buffer > and returns control back to crashdd. > > 4. Crashdd exposes the buffer as a file via > /proc/crashdd/<driver>/<dump_file>. > > 5. User space script (/usr/lib/kdump/kdump-lib-initramfs.sh) copies > the entire /proc/crashdd/ directory to /var/crash/ directory. > > Patch 1 adds crashdd module to allow drivers to register callback to > collect the device specific hardware/firmware logs. The module also > exports /proc/crashdd/ directory containing the hardware/firmware logs. > > Patch 2 shows a cxgb4 driver example using the API to collect > hardware/firmware logs in crash recovery kernel, before hardware is > initialized. The logs for the devices are made available under > /proc/crashdd/cxgb4/ directory. > > Suggestions and feedback will be much appreciated. > > Thanks, > Rahul > > RFC v1: https://www.spinics.net/lists/netdev/msg486562.html > > --- > v2: > - Added new crashdd module that exports /proc/crashdd/ containing > driver's registered hardware/firmware logs in patch 1. > - Replaced the API to allow drivers to register their hardware/firmware > log collect routine in crash recovery kernel in patch 1. > - Updated patch 2 to use the new API in patch 1. > > Rahul Lakkireddy (2): > proc/crashdd: add API to collect hardware dump in second kernel > cxgb4: collect hardware dump in second kernel > > drivers/net/ethernet/chelsio/cxgb4/cxgb4.h | 4 + > drivers/net/ethernet/chelsio/cxgb4/cxgb4_cudbg.c | 25 +++ > drivers/net/ethernet/chelsio/cxgb4/cxgb4_cudbg.h | 3 + > drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c | 12 ++ > fs/proc/Kconfig | 11 + > fs/proc/Makefile | 1 + > fs/proc/crashdd.c | 263 +++++++++++++++++++++++ > include/linux/crashdd.h | 43 ++++ > 8 files changed, 362 insertions(+) > create mode 100644 fs/proc/crashdd.c > create mode 100644 include/linux/crashdd.h > > -- > 2.14.1 > Does anyone have any comments with this approach? If there are no comments, then I'll re-spin this RFC to Patch series. Thanks, Rahul _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
