From: Dave Anderson <anderson@xxxxxxxxxx> Subject: Re: [PATCH] kmem, snap: iomem/ioport display and vmcore snapshot support Date: Tue, 13 Mar 2012 10:17:20 -0400 (EDT) > > > ----- Original Message ----- >> Some days ago I was in a situation that I had to convert vmcore in >> kvmdump format into ELF since some extension module we have locally >> can be used only on relatively old crash utility, around version 4, >> but such old crash utility cannot handle kvmdump format. > > That's a pretty weak argument -- what did crash version ~4 have > that the latest version does not? I don't recall ever removing > any functionality w/respect to extension module without replacing > it with a better interface. In other words, why can't you fix your > local extension module? I need a better reason for modifying > the snap module other than that. > I don't know the detail of the local extension module. The man who requested a help to me explained that his module gets information of vmcore using crash (gdb) scripts and retrives values from the scripts' output via pipe. While old crash behaves well, recent ones appear to hang in the situation where both reading and writing sides wait each other. Is there any difference of behaviour on communication with gdb? Anyway it's natural that we should modify the extension module, and we'll do that soon. The patch for snap command was a workaround, but there's merit to the patch that it makes it possible to use it as handy vmcore conversion tool, not just as live kernel dump command, so I've posted this here. By this, snap command will become able to convert all the format currently crash supports into ELF. Though I have yet to test this, this can convert lkcd foramt into ELF, for example. Someone might want to use this for vmcore not suppoted by Makedumpfile. > > Why reinvent the wheel? The "dev -i" command does all of the above, plus > gives you the resource structure address: > > crash> dev -i > RESOURCE RANGE NAME > ffffffff80312080 0000-ffff PCI IO <cut> I myself thought it's strange if it's not present. Before making my patch, I did minimum check by searching crash source code for related symbols such as ``resource'', but I didn't find anything. Now I see some symbols found with the same keyword. I think I did something wrong at that time. Thanks. HATAYAMA, Daisuke -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
