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From: Vivek Goyal <vgoyal@redhat.com>
To: "K.Prasad" <prasad@linux.vnet.ibm.com>
Cc: oomichi@mxs.nes.nec.co.jp, "Luck, Tony" <tony.luck@intel.com>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	tachibana@mxm.nes.nec.co.jp, Andi Kleen <andi@firstfloor.org>,
	anderson@redhat.com, "Eric W. Biederman" <ebiederm@xmission.com>,
	Borislav Petkov <bp@alien8.de>,
	crash-utility@redhat.com
Subject: Re: [Patch 1/4][kernel][slimdump] Add new elf-note of type NT_NOCOREDUMP to capture slimdump
Date: Wed, 5 Oct 2011 11:40:11 -0400	[thread overview]
Message-ID: <20111005154011.GD30146@redhat.com> (raw)
In-Reply-To: <20111005074116.GC2235@in.ibm.com>

On Wed, Oct 05, 2011 at 01:11:16PM +0530, K.Prasad wrote:

[..]
> > Again, note_name and desc_msg seem to be only two exports. Frankly desc
> > string seems pretty obivious and we should be able to ignore it. So just
> > exporting PANIC_MCE=true or something like that in case of MCE. 
> >
> 
> Yes, adding a new field to the VMCOREINFO note would have been much
> simpler but there's a second part to the kdump + fatal MCE problem which
> will need a new elf-note to solve.
> 
> On a system containing 'poisoned' pages (generated as a result of
> detecting UC errors which haven't been 'consumed'), if a software bug results
> in crashing the machine, the ensuing kdump operation will read from the
> faulty memory location. This will trigger a new crash within the context
> of the kexec'ed kernel and we want to avoid this.

I think in other mail you mentioned that it is not known what happens
if we try to read pages marked as "poisoned".

> 
> The plan is to pass-down the list of poisoned memory pages to the second
> kernel using an elf-note so that these pages are left untouched during
> dump capture. I'm working on an implementation of the same and should
> have patches soon.

I would say let us first figure out what happens while reading a poisoned
page and is this a problem before working on a solution.

Thanks
Vivek

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WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com>
To: "K.Prasad" <prasad@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, crash-utility@redhat.com,
	kexec@lists.infradead.org, Andi Kleen <andi@firstfloor.org>,
	"Luck, Tony" <tony.luck@intel.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	anderson@redhat.com, tachibana@mxm.nes.nec.co.jp,
	oomichi@mxs.nes.nec.co.jp, Borislav Petkov <bp@alien8.de>
Subject: Re: [Patch 1/4][kernel][slimdump] Add new elf-note of type NT_NOCOREDUMP to capture slimdump
Date: Wed, 5 Oct 2011 11:40:11 -0400	[thread overview]
Message-ID: <20111005154011.GD30146@redhat.com> (raw)
In-Reply-To: <20111005074116.GC2235@in.ibm.com>

On Wed, Oct 05, 2011 at 01:11:16PM +0530, K.Prasad wrote:

[..]
> > Again, note_name and desc_msg seem to be only two exports. Frankly desc
> > string seems pretty obivious and we should be able to ignore it. So just
> > exporting PANIC_MCE=true or something like that in case of MCE. 
> >
> 
> Yes, adding a new field to the VMCOREINFO note would have been much
> simpler but there's a second part to the kdump + fatal MCE problem which
> will need a new elf-note to solve.
> 
> On a system containing 'poisoned' pages (generated as a result of
> detecting UC errors which haven't been 'consumed'), if a software bug results
> in crashing the machine, the ensuing kdump operation will read from the
> faulty memory location. This will trigger a new crash within the context
> of the kexec'ed kernel and we want to avoid this.

I think in other mail you mentioned that it is not known what happens
if we try to read pages marked as "poisoned".

> 
> The plan is to pass-down the list of poisoned memory pages to the second
> kernel using an elf-note so that these pages are left untouched during
> dump capture. I'm working on an implementation of the same and should
> have patches soon.

I would say let us first figure out what happens while reading a poisoned
page and is this a problem before working on a solution.

Thanks
Vivek

  reply	other threads:[~2011-10-05 15:40 UTC|newest]

Thread overview: 102+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-03  7:07 [Patch 0/4] Slimdump framework using NT_NOCOREDUMP elf-note K.Prasad
2011-10-03  7:07 ` K.Prasad
2011-10-03  7:32 ` [Patch 1/4][kernel][slimdump] Add new elf-note of type NT_NOCOREDUMP to capture slimdump K.Prasad
2011-10-03  7:32   ` K.Prasad
2011-10-03 10:10   ` Eric W. Biederman
2011-10-03 10:10     ` Eric W. Biederman
2011-10-03 12:03     ` K.Prasad
2011-10-03 12:03       ` K.Prasad
2011-10-04  6:34       ` Borislav Petkov
2011-10-04  6:34         ` Borislav Petkov
2011-10-05  7:07         ` K.Prasad
2011-10-05  7:07           ` K.Prasad
2011-10-05  7:31           ` Borislav Petkov
2011-10-05  7:31             ` Borislav Petkov
2011-10-05  9:47             ` K.Prasad
2011-10-05  9:47               ` K.Prasad
2011-10-05 12:41               ` Borislav Petkov
2011-10-05 12:41                 ` Borislav Petkov
2011-10-05 15:52               ` Vivek Goyal
2011-10-05 15:52                 ` Vivek Goyal
2011-10-05 16:00                 ` Valdis.Kletnieks
2011-10-05 16:16                   ` Borislav Petkov
2011-10-05 16:16                     ` Borislav Petkov
2011-10-05 17:20                     ` Vivek Goyal
2011-10-05 17:20                       ` Vivek Goyal
2011-10-05 17:13                   ` Vivek Goyal
2011-10-05 17:13                     ` Vivek Goyal
2011-10-05 11:55             ` Valdis.Kletnieks
2011-10-05 12:31               ` Borislav Petkov
2011-10-05 12:31                 ` Borislav Petkov
2011-10-05 15:19           ` Vivek Goyal
2011-10-05 15:19             ` Vivek Goyal
2011-10-05 15:30           ` Vivek Goyal
2011-10-05 15:30             ` Vivek Goyal
2011-10-03 22:53     ` Luck, Tony
2011-10-03 22:53       ` Luck, Tony
2011-10-04 14:04   ` Vivek Goyal
2011-10-04 14:04     ` Vivek Goyal
2011-10-05  7:18     ` K.Prasad
2011-10-05  7:18       ` K.Prasad
2011-10-05  7:33       ` Borislav Petkov
2011-10-05  7:33         ` Borislav Petkov
2011-10-05  9:23         ` K.Prasad
2011-10-05  9:23           ` K.Prasad
2011-10-05 15:25       ` Vivek Goyal
2011-10-05 15:25         ` Vivek Goyal
2011-10-07 16:12         ` K.Prasad
2011-10-07 16:12           ` K.Prasad
2011-10-10  7:07           ` Borislav Petkov
2011-10-10  7:07             ` Borislav Petkov
2011-10-11 18:44             ` K.Prasad
2011-10-11 18:44               ` K.Prasad
2011-10-11 18:59               ` Luck, Tony
2011-10-11 18:59                 ` Luck, Tony
2011-10-12  0:20               ` Andi Kleen
2011-10-12  0:20                 ` Andi Kleen
2011-10-12 10:44               ` Borislav Petkov
2011-10-12 10:44                 ` Borislav Petkov
2011-10-12 15:59                 ` Vivek Goyal
2011-10-12 15:59                   ` Vivek Goyal
2011-10-12 15:51               ` Vivek Goyal
2011-10-12 15:51                 ` Vivek Goyal
2011-10-14 11:30                 ` K.Prasad
2011-10-14 11:30                   ` K.Prasad
2011-10-14 14:14                   ` Vivek Goyal
2011-10-14 14:14                     ` Vivek Goyal
2011-10-18 17:41                     ` K.Prasad
2011-10-18 17:41                       ` K.Prasad
2011-10-11 18:55             ` Luck, Tony
2011-10-04 14:30   ` Vivek Goyal
2011-10-04 14:30     ` Vivek Goyal
2011-10-05  7:41     ` K.Prasad
2011-10-05  7:41       ` K.Prasad
2011-10-05 15:40       ` Vivek Goyal [this message]
2011-10-05 15:40         ` Vivek Goyal
2011-10-05 15:58         ` Luck, Tony
2011-10-05 16:25           ` Borislav Petkov
2011-10-05 16:25             ` Borislav Petkov
2011-10-05 17:10           ` Vivek Goyal
2011-10-05 17:10             ` Vivek Goyal
2011-10-05 17:20             ` Borislav Petkov
2011-10-05 17:20               ` Borislav Petkov
2011-10-05 17:29               ` Vivek Goyal
2011-10-05 17:29                 ` Vivek Goyal
2011-10-05 17:43                 ` Borislav Petkov
2011-10-05 17:43                   ` Borislav Petkov
2011-10-05 18:00                 ` Dave Anderson
2011-10-05 18:00                   ` Dave Anderson
2011-10-05 18:09                   ` Vivek Goyal
2011-10-05 18:09                     ` Vivek Goyal
2011-10-04 15:04   ` Nick Bowler
2011-10-04 15:04     ` Nick Bowler
2011-10-07 16:36     ` K.Prasad
2011-10-07 16:36       ` K.Prasad
2011-10-07 18:19       ` Nick Bowler
2011-10-07 18:19         ` Nick Bowler
2011-10-03  7:35 ` [Patch 2/4][kexec-tools] Recognise NT_NOCOREDUMP elf-note type K.Prasad
2011-10-03  7:35   ` K.Prasad
2011-10-03  7:37 ` [Patch 3/4][makedumpfile] Capture slimdump if elf-note NT_NOCOREDUMP present K.Prasad
2011-10-03  7:37   ` K.Prasad
2011-10-03  7:45 ` [Patch 4/4][crash] Recognise elf-note of type NT_NOCOREDUMP before vmcore analysis K.Prasad
2011-10-03  7:45   ` K.Prasad

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