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From: Ingo Molnar <mingo@kernel.org>
To: Baoquan He <bhe@redhat.com>
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86/boot/KASLR: Skip relocation handling in no kaslr case
Date: Mon, 26 Jun 2017 11:47:38 +0200	[thread overview]
Message-ID: <20170626094737.d2pzetkhe2sorn6m@gmail.com> (raw)
In-Reply-To: <1498314309-18502-1-git-send-email-bhe@redhat.com>


* Baoquan He <bhe@redhat.com> wrote:

> Kdump kernel will reset to firmware after crash is trigered when
> crashkernel=xxM,high is added to kernel command line. Kexec has the
> same phenomenon. This only happened on system with kaslr code
> compiled in and kernel option 'nokaslr'is added. Both of them works
> well when kaslr is enabled.
> 
> When crashkernel high is set or kexec case, kexec/kdump kernel will be
> put above 4G. Since we assign the original loading address of kernel to
> virt_addr as initial value, the virt_addr will be larger than 1G if kaslr
> is disabled, it exceeds the kernel mapping size which is only 1G. Then
> it will cause relocation handling error in handle_relocations().

So instead of whacking yet another kexec mole, how could we turn this into a more 
debuggable warning (either during build or during the failed bootup) instead of a 
crash and reset (triple fault?) back to the BIOS screen?

If kexec/kdump wants to do crazy things they should at least be _debuggable_ in a 
straightforward manner.

Thanks,

	Ingo

       reply	other threads:[~2017-06-26  9:47 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1498314309-18502-1-git-send-email-bhe@redhat.com>
2017-06-26  9:47 ` Ingo Molnar [this message]
2017-06-26 10:43   ` Baoquan He
2017-06-27  8:34     ` Ingo Molnar
2017-06-27  8:55       ` Baoquan He
2017-06-27 22:42 ` Kees Cook
2017-06-27 23:24   ` Baoquan He
2017-06-27 23:33     ` Baoquan He
2017-07-05 19:06     ` Kees Cook
2017-07-06 13:28       ` Baoquan He
2017-07-06 13:54         ` Baoquan He
2017-06-24 14:16 Baoquan He
2017-06-24 14:23 ` Baoquan He

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