On Tue, 2007-03-20 at 11:18 +0900, Ken'ichi Ohmichi wrote: > Hi Bob, > > Thank you for the great report. You are welcome. Before continuing the discussion of issues with proposed changes to ELF dumpfile generation, I'd like to recap where we are and suggest a couple of actions. 1) Makedumpfile patch: Ken'ichi Ohmichi's email of Wed, 7 Mar 2007 10:43:38 +0900 contained the patch "point_same_zero_page.patch". That patch contains the nice solution to remove redundant zero page images from the diskdump dump file by pointing the page descriptors of zero pages to a common zero image. I suggest that this patch should be applied to makedumpfile as soon as possible, without waiting on a possible solution to the ELF situation. As described in my report, ELF and diskdump dump files have not shown identical behavior in the past. This patch makes diskdump dump files more accurate, and leaves ELF dump files at the same level of accuracy that they have always had. 2) Crash patch: Ken'ichi Ohmichi's crash patch in the email of Tue, 20 Mar 2007 11:18:02 +0900 should be submitted to crash as soon as possible. The error message is a bit wordy, and could be reduced to prevent wrap on 80 column windows, as suggested below, but that is a minor issue, since the output is already a bit unwieldy: Current patch prints on 80-column screen (three levels of crash are now reporting the problem): crash> x/xg 0xffff810000005ff0 0xffff810000005ff0: gdb: diskdump: cannot access paddr(5ff0) due to the excl uded page gdb: seek error: kernel virtual address: ffff810000005ff0 type: "gdb_readmem_ca llback" Cannot access memory at address 0xffff810000005ff0 crash> With a shortened message in diskdump.c: crash> x/xg 0xffff810000005ff0 0xffff810000005ff0: gdb: diskdump: paddr(5ff0) excluded from dump gdb: seek error: kernel virtual address: ffff810000005ff0 type: "gdb_readmem_ca llback" Cannot access memory at address 0xffff810000005ff0 crash> With these two patches, crash reports the contents of diskdump dump files produced by makedumpfile correctly. Zero content pages that have not been excluded for other reasons remain accessible, and pages that have really been excluded become inaccessible, instead of showing 0x0 contents. Crash should continue to read old dump files as before, because of the change in version number in the dumpfiles. Bob Montgomery -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
