Mon, Apr 02, 2018 at 02:30:45PM CEST, rahul.lakkireddy@xxxxxxxxxxx wrote: >On Monday, April 04/02/18, 2018 at 14:41:43 +0530, Jiri Pirko wrote: >> Fri, Mar 30, 2018 at 08:42:00PM CEST, ebiederm@xxxxxxxxxxxx wrote: >> >Rahul Lakkireddy <rahul.lakkireddy@xxxxxxxxxxx> writes: >> > >> >> On Friday, March 03/30/18, 2018 at 16:09:07 +0530, Jiri Pirko wrote: >> >>> Sat, Mar 24, 2018 at 11:56:33AM CET, rahul.lakkireddy@xxxxxxxxxxx wrote: >> >>> >Add a new module crashdd that exports the /sys/kernel/crashdd/ >> >>> >directory in second kernel, containing collected hardware/firmware >> >>> >dumps. >> >>> > >> >>> >The sequence of actions done by device drivers to append their device >> >>> >specific hardware/firmware logs to /sys/kernel/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 >> >>> >/sys/kernel/crashdd/<driver>. Then, it allocates the buffer with >> >>> >> >>> This smells. I need to identify the exact ASIC instance that produced >> >>> the dump. To identify by driver name does not help me if I have multiple >> >>> instances of the same driver. This looks wrong to me. This looks like >> >>> a job for devlink where you have 1 devlink instance per 1 ASIC instance. >> >>> >> >>> Please see: >> >>> http://patchwork.ozlabs.org/project/netdev/list/?series=36524 >> >>> >> >>> I bevieve that the solution in the patchset could be used for >> >>> your usecase too. >> >>> >> >>> >> >> >> >> The sysfs approach proposed here had been dropped in favour exporting >> >> the dumps as ELF notes in /proc/vmcore. >> >> >> >> Will be posting the new patches soon. >> > >> >The concern was actually how you identify which device that came from. >> >Where you read the identifier changes but sysfs or /proc/vmcore the >> >change remains valid. >> >> Yeah. I still don't see how you link the dump and the device. > >In our case, the dump and the device are being identified by the >driver’s name followed by its corresponding pci bus id. I’ve posted an >example in my v3 series: > >https://www.spinics.net/lists/netdev/msg493781.html > >Here’s an extract from the link above: > ># readelf -n /proc/vmcore > >Displaying notes found at file offset 0x00001000 with length 0x04003288: >Owner Data size Description >VMCOREDD_cxgb4_0000:02:00.4 0x02000fd8 Unknown note type:(0x00000700) >VMCOREDD_cxgb4_0000:04:00.4 0x02000fd8 Unknown note type:(0x00000700) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >CORE 0x00000150 NT_PRSTATUS (prstatus structure) >VMCOREINFO 0x0000074f Unknown note type: (0x00000000) > >Here, for my two devices, the dump’s names are >VMCOREDD_cxgb4_0000:02:00.4 and VMCOREDD_cxgb4_0000:04:00.4. > >It’s really up to the callers to write their own unique name for the >dump. The name is appended to “VMCOREDD_” string. > >> Rahul, did you look at the patchset I pointed out? > >For devlink, I think the dump name would be identified by >bus_type/device_name; i.e. “pci/0000:02:00.4” for my example. >Is my understanding correct? Yes. > >Thanks, >Rahul
