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From: Dave Anderson <anderson@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Kazuhito Hagio <k-hagio@ab.jp.nec.com>,
	Lianbo Jiang <lijiang@redhat.com>,
	linux-kernel@vger.kernel.org, kexec@lists.infradead.org,
	tglx@linutronix.de, mingo@redhat.com, x86@kernel.org,
	akpm@linux-foundation.org, bhe@redhat.com, dyoung@redhat.com,
	linux-doc@vger.kernel.org
Subject: Re: [PATCH 1/2 v6] kdump: add the vmcoreinfo documentation
Date: Mon, 14 Jan 2019 15:26:32 -0500 (EST)	[thread overview]
Message-ID: <221183717.69773903.1547497592624.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <20190114201812.GT2773@zn.tnic>



----- Original Message -----
> On Mon, Jan 14, 2019 at 03:07:33PM -0500, Dave Anderson wrote:
> > That's what it *does* utilize -- it takes a standalone vmcore dumpfile, and
> > pulls out the OSRELEASE string from it, so that a user can determine what
> > vmlinux file should be used with that vmcore for normal crash analysis.
> 
> And the vmcoreinfo is part of the vmcore, right?

Correct.

> 
> So it can just as well read out the address of init_uts_ns and get the
> kernel version from there.

No.  It needs *both* the vmlinux file and the vmcore file in order to read kernel
virtual memory, so just having a kernel virtual address is insufficient.

So it's a chicken-and-egg situation.  This particular --osrelease option is used
to determine *what* vmlinux file would be required for an actual crash analysis 
session.

Dave

 

WARNING: multiple messages have this Message-ID (diff)
From: Dave Anderson <anderson@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Kazuhito Hagio <k-hagio@ab.jp.nec.com>,
	Lianbo Jiang <lijiang@redhat.com>,
	bhe@redhat.com, linux-doc@vger.kernel.org, x86@kernel.org,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	mingo@redhat.com, tglx@linutronix.de, dyoung@redhat.com,
	akpm@linux-foundation.org
Subject: Re: [PATCH 1/2 v6] kdump: add the vmcoreinfo documentation
Date: Mon, 14 Jan 2019 15:26:32 -0500 (EST)	[thread overview]
Message-ID: <221183717.69773903.1547497592624.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <20190114201812.GT2773@zn.tnic>



----- Original Message -----
> On Mon, Jan 14, 2019 at 03:07:33PM -0500, Dave Anderson wrote:
> > That's what it *does* utilize -- it takes a standalone vmcore dumpfile, and
> > pulls out the OSRELEASE string from it, so that a user can determine what
> > vmlinux file should be used with that vmcore for normal crash analysis.
> 
> And the vmcoreinfo is part of the vmcore, right?

Correct.

> 
> So it can just as well read out the address of init_uts_ns and get the
> kernel version from there.

No.  It needs *both* the vmlinux file and the vmcore file in order to read kernel
virtual memory, so just having a kernel virtual address is insufficient.

So it's a chicken-and-egg situation.  This particular --osrelease option is used
to determine *what* vmlinux file would be required for an actual crash analysis 
session.

Dave

 

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  reply	other threads:[~2019-01-14 20:26 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-10 12:19 [PATCH 0/2 v6] kdump,vmcoreinfo: Export the value of sme mask to vmcoreinfo Lianbo Jiang
2019-01-10 12:19 ` [PATCH 0/2 v6] kdump, vmcoreinfo: " Lianbo Jiang
2019-01-10 12:19 ` [PATCH 1/2 v6] kdump: add the vmcoreinfo documentation Lianbo Jiang
2019-01-10 12:19   ` Lianbo Jiang
2019-01-11 12:33   ` Borislav Petkov
2019-01-11 12:33     ` Borislav Petkov
2019-01-14  1:52     ` lijiang
2019-01-14  1:52       ` lijiang
2019-01-14  9:10       ` Borislav Petkov
2019-01-14  9:10         ` Borislav Petkov
2019-01-14 17:48     ` Kazuhito Hagio
2019-01-14 17:48       ` Kazuhito Hagio
2019-01-14 18:01       ` Borislav Petkov
2019-01-14 18:01         ` Borislav Petkov
2019-01-14 18:58         ` Dave Anderson
2019-01-14 18:58           ` Dave Anderson
2019-01-14 19:21           ` Borislav Petkov
2019-01-14 19:21             ` Borislav Petkov
2019-01-14 19:36             ` Dave Anderson
2019-01-14 19:36               ` Dave Anderson
2019-01-14 19:59               ` Borislav Petkov
2019-01-14 19:59                 ` Borislav Petkov
2019-01-14 20:07                 ` Dave Anderson
2019-01-14 20:07                   ` Dave Anderson
2019-01-14 20:18                   ` Borislav Petkov
2019-01-14 20:18                     ` Borislav Petkov
2019-01-14 20:26                     ` Dave Anderson [this message]
2019-01-14 20:26                       ` Dave Anderson
2019-01-14 20:35                       ` Borislav Petkov
2019-01-14 20:35                         ` Borislav Petkov
2019-01-14 20:49                         ` Dave Anderson
2019-01-14 20:49                           ` Dave Anderson
2019-01-15 10:06                           ` Borislav Petkov
2019-01-15 10:06                             ` Borislav Petkov
2019-01-15 11:00                           ` lijiang
2019-01-15 11:00                             ` lijiang
2019-01-11 14:56   ` Borislav Petkov
2019-01-11 14:56     ` Borislav Petkov
2019-01-14  5:30     ` lijiang
2019-01-14  5:30       ` lijiang
2019-01-14  9:15       ` Borislav Petkov
2019-01-14  9:15         ` Borislav Petkov
2019-01-15  9:41         ` lijiang
2019-01-15  9:41           ` lijiang
2019-01-15 10:09   ` [tip:x86/kdump] kdump: Document kernel data exported in the vmcoreinfo note tip-bot for Lianbo Jiang
2019-01-10 12:19 ` [PATCH 2/2 v6] kdump,vmcoreinfo: Export the value of sme mask to vmcoreinfo Lianbo Jiang
2019-01-10 12:19   ` [PATCH 2/2 v6] kdump, vmcoreinfo: " Lianbo Jiang
2019-01-11 15:15   ` [tip:x86/kdump] x86/kdump: Export the SME " tip-bot for Lianbo Jiang

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