On Monday, April 04/15/19, 2019 at 21:16:49 +0530, Dave Anderson wrote:
>
>
> ----- Original Message -----
> > Hi Dave,
> >
> > On Saturday, April 04/13/19, 2019 at 00:39:09 +0530, Dave Anderson wrote:
> > >
> > > Hi Surenda,
> > >
> > > Great -- I've been looking forward for this patch set to arrive.
> > >
> > > A couple things...
> > >
> > > First, I'm going to need two sample vmcores (one ELF, one compressed kdump)
> > > along with the associated vmlinux. You can contact me off-list with
> > > details
> > > on how we can arrange a transfer.
> > >
> > > Second, I do not want to add a new command. I rarely do so -- in fact,
> > > the only times since the original crash utility was released was in 2012,
> > > when the "ipcs" and "tree" commands were added in crash-6.0.7 and
> > > crash-6.0.8.
> > > New functionality is typically added as an option to an existing command.
> > > And in this case, the natural location to put it is in the existing "dev"
> > > command, and the devdump_extract() function can be moved into dev.c.
> > > (FWIW, you can add your Chelsio copyright at the top of that file)
> > >
> >
> > Ok, thanks for the suggestion. We will move the logic to dev command,
> > instead.
> >
> > We're thinking along the lines of following sample commands:
> >
> > Display the available device dumps
> > crash> dev -v
> > INDEX NAME OFFSET SIZE
> > 0 cxgb4_0000:02:00.4 0x278 33558464
> > 1 cxgb4_0000:03:00.4 0x2001278 33558464
> >
> > Extract device dump at specified index
> > crash> devdump -v 0 -f device_dump_0.bin
> > 33558464 bytes copied from 0x278 to device_dump_0.bin
> >
> > Let us know your thoughts.
>
> Hi Surenda,
>
> I've got your sample files -- thanks for them, I really appreciate it.
>
> Here are my thoughts...
>
> You probably want to make "-V" display the list of available device dumps in the
> vmcore, and make "-v <index>" select a singular device for dumping.
>
Thanks for the suggestion. We will follow this approach.
> I also have a question re: the note contents. Is it up to the individual device
> as to what format the dump contents are made up of? Are they always binary
> dumps, or could a device dump ASCII log data or something to that effect?
>
They are generally binary in nature. However, it is really up to
the individual device to decide the format on how to save its
dump contents.
> I ask because I see that you are calling display_memory() using these arguments:
>
> void
> display_memory_from_file_offset(ulonglong addr, long count, void *opt)
> {
> display_memory(addr, count, DISPLAY_RAW | ASCII_ENDLINE | HEXADECIMAL,
> FILEADDR, opt);
> }
>
> Since you are using DISPLAY_RAW, display_memory() will simply copy the
> note data unmodified directly to the file, and the ASCII_ENDLINE and
> HEXADECIMAL arguments are ignored. So it's not clear why you added them?
You are correct. It should have been only DISPLAY_RAW. We will fix in
next version.
> But since you did, I'm now wondering whether it would be useful for
> a user to optionally dump a human-readable HEXADECIMAL/ASCII_ENDLINE
> formatted display of the data to the screen? If so, then perhaps if
> the "-v index" option is used alone *without* a file specified,
> why not just do a translated device dump to the screen?
We notice that rd command can manipulate the output using below
options:
rd [-adDxN][-8|-16|-32|-64]
Let us know if it is recommended to duplicate above options from rd to
dev command for manipulating screen output.
We are thinking, dev -v should only be used for doing "full" raw dump
to file. Since dev -V already shows offset and size of dump, rd -f
can be used for more control over manipulating the dump output to
screen or file.
What do you think?
>
> So to summarize, my suggestions would be:
>
> dev -V dump the list of device dumps
> dev -v <index> [ -r file ] select and display one device dump, either in
> human-readable format to the screen by default,
> or optionally copy it raw to a file
>
> Thanks,
> Dave
>
>
Thanks,
Surendra
>
>
> >
> > > Third, there are some aesthetic changes that should be made in order
> > > to have the display use a more traditional output format like those
> > > used by other commands, e.g., with a single header with NAME, OFFSET and
> > > SIZE columns.
> > >
> >
> > Ok, We will fix this in next version.
> >
> > > Other than that, this looks good on paper!
> > >
> > > Thanks,
> > > Dave
> > >
> >
> > Thanks
> > Surendra
> >
> >
> > >
> > > ----- Original Message -----
> > > > When kernel panic happens and kdump crash kernel is loaded, device
> > > > drivers enabled in the kdump crash kernel collect device specific
> > > > snapshot of the hardware/firmware state of their underlying devices.
> > > > These snapshots are exported as ELF notes with note type NT_VMCOREDD
> > > > (i.e., 0x700) in vmcore [1].
> > > >
> > > > This series of patches enhance crash utility to analyze and
> > > > extract these hardware specific device dumps from vmcore using
> > > > a new "devdump" command.
> > > >
> > > > Patches 1 and 2 enhance help -D to parse NT_VMCOREDD ELF notes
> > > > in ELF vmcore and KDUMP vmcore, respectively.
> > > >
> > > > Patches 3 and 4 implement devdump command to analyze and extract
> > > > hardware specific device dumps from ELF vmcore and KDUMP vmcore,
> > > > respectively.
> > > >
> > > > Suggestions and feedback will be much appreciated.
> > > >
> > > > Thanks,
> > > > Surendra
> > > >
> > > > [1] https://lkml.org/lkml/2018/5/2/190
> > > >
> > > > Surendra Mobiya (4):
> > > > parse NT_VMCOREDD ELF notes in ELF vmcore
> > > > parse NT_VMCOREDD ELF notes in KDUMP vmcore
> > > > add devdump command to extract NT_VMCOREDD from ELF vmcore
> > > > enhance devdump command to extract NT_VMCOREDD from KDUMP vmcore
> > > >
> > > > Makefile | 4 +--
> > > > defs.h | 16 +++++++++
> > > > devdump.c | 114
> > > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > > diskdump.c | 71 +++++++++++++++++++++++++++++++++++-
> > > > global_data.c | 1 +
> > > > help.c | 23 ++++++++++++
> > > > memory.c | 7 ++++
> > > > netdump.c | 89 +++++++++++++++++++++++++++++++++++++++++++--
> > > > netdump.h | 3 ++
> > > > vmcore.h | 36 +++++++++++++++++++
> > > > 10 files changed, 359 insertions(+), 5 deletions(-)
> > > > create mode 100644 devdump.c
> > > > create mode 100644 vmcore.h
> > > >
> > > > --
> > > > 1.8.3.1
> > > >
> > > >
> >
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