----- Original Message ----- > Hello Dave, > > Thanks for your reply. > > We can use two methods to indicate that the incomplete vmcore is a "fixed" one, > 1. Use a flag in elf/kdump dumpfile(like "e_flags" in ELF header and "status" > in disk_dump_header) to indicate it has been "fixed". But actually the > kdump-compressed file needn't to use such a flag, for we just change the > data write order of this format. I don't understand. First, let's stop using the "fixed" description. It is definitely *not* fixed, but rather it is still a bogus, incomplete, dumpfile, and the user should be made aware of that fact. For compressed kdumps, the disk_dump_header.status field currently uses these three bits: #define DUMP_DH_COMPRESSED_ZLIB 0x1 /* page is compressed with zlib */ #define DUMP_DH_COMPRESSED_LZO 0x2 /* page is compressed with lzo */ #define DUMP_DH_COMPRESSED_SNAPPY 0x4 /* page is compressed with snappy */ Can you please simply add a DUMP_DH_COMPRESSED_INCOMPLETE flag? With respect to ELF vmcores, the processor-specific e_flags field is unused by the crash utility, and it appears that makedumpfile always sets it to zero. But I'm not sure what the kernel does when /proc/vmcore is created? Could there be e_flags bits set there that a direct-copy of /proc/vmcore might contain? That's why I suggested a unique ELF note. Then, if the flag is set, the crash utility can display "[INCOMPLETE]" next to the dumpfile file name in the initial system banner and by the "sys" command. And in the highly-likely event where the vmcore fails to initialize -- in that case "crash -d1" can display the header contents immediately during invocation. That way, instead of users complaining about the crash utility, the blame can be placed where it belongs. > 2. We can just let makedumpfile change the "fixed" dumpfile's filename automatically. > Such as add a "-truncated" flag after those dumpfiles. You probably should do that -- in *addition* to setting a flag in the header. Since there's no way to prevent a user from re-naming the file, without a flag, there would be no way of confirming that it was a bogus dumpfile to begin with. Thanks, Dave
