Re: [PATCH 1/2 v6] kdump: add the vmcoreinfo documentation

Borislav Petkov
2019-01-14T19:21:53Z

On Mon, Jan 14, 2019 at 01:58:32PM -0500, Dave Anderson wrote:
> Preferably it would be left as-is. The crash utility has a "crash --osrelease vmcore"
> option that only looks at the dumpfile header, and just dump the string. With respect
> to compressed kdumps, crash could alternatively look at the utsname data that is stored
> in the diskdump_header.utsname field, but with ELF vmcores, there is no such back-up.

Well, there is:

00000000 4f 53 52 45 4c 45 41 53 45 3d 35 2e 30 2e 30 2d |OSRELEASE=5.0.0-|
00000010 72 63 32 2b 0a 50 41 47 45 53 49 5a 45 3d 34 30 |rc2+.PAGESIZE=40|
00000020 39 36 0a 53 59 4d 42 4f 4c 28 6d 65 6d 5f 73 65 |96.SYMBOL(mem_se|
00000030 63 74 69 6f 6e 29 3d 66 66 66 66 66 66 66 66 38 |ction)=ffffffff8|
00000040 34 35 31 61 31 61 38 0a 53 59 4d 42 4f 4c 28 69 |451a1a8.SYMBOL(i|
00000050 6e 69 74 5f 75 74 73 5f 6e 73 29 3d 66 66 66 66 |nit_uts_ns)=ffff|
^^^^
00000060 66 66 66 66 38 32 30 31 33 35 34 30 0a 53 59 4d |ffff82013540
^^^^^^^^^^^^

This address has it.

> What's the problem with leaving it alone?

The problem is that I'd like to get all those vmcoreinfo exports under
control and to not have people frivolously export whatever they feel
like, for obvious reasons, and to get rid of the duplicate/unused pieces
being part of vmcoreinfo.

I'm guessing removing OSRELEASE would simplify the kernel a bit by
getting rid of the VMCOREINFO_OSRELEASE define and export, and userspace
can read out the kernel version from init_uts_ns which is also exported.

--
Regards/Gruss,
Boris.

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