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From: Yinghai Lu <yinghai@kernel.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org, Rob Landley <rob@landley.net>,
	Matt Fleming <matt.fleming@intel.com>
Subject: Re: [PATCH v3 11/12] x86, boot: add fields to support load bzImage and ramdisk high
Date: Sat, 24 Nov 2012 13:30:41 -0800	[thread overview]
Message-ID: <CAE9FiQWKzH+BLwak5-n2px1Yhti872o=Qte-v_8N_5X3YSJ=5A@mail.gmail.com> (raw)
In-Reply-To: <50B124E9.400@zytor.com>

On Sat, Nov 24, 2012 at 11:50 AM, H. Peter Anvin <hpa@zytor.com> wrote:
> On 11/24/2012 09:32 AM, H. Peter Anvin wrote:
>>
>> On 11/24/2012 04:37 AM, Eric W. Biederman wrote:
>>>
>>>
>>> Certainly /sbin/kexec isn't bothering to calculate the end of the setup
>>> header and just being far more conservative and using all of the 16bit
>>> real mode code as it's initializer.
>>>
>>
>> That's not conservative... that's just plain wrong.  It means you're
>> initializing the fields in struct boot_params with garbage instead of a
>> predictable value (zero).
>>
>> We could work around it with a sentinel hack... except you *also*
>> probably modify *some* fields and now we have a horrid mix of
>> initialized and uninitialized fields to sort out... and there really
>> isn't any sane way for the kernel to sort that out.
>>
>> We have a huge problem on our hands now because of it.
>>
>
> So, given the mess we now have on our hands... any suggestions how to best
> solve it?  There is the option of simply declaring old kexec binaries
> broken; they will then not work reliably with newer kernels, if they even
> work reliably now -- it is hard to know for certain.

yes, if the user updates kernel to be kexeced, then would be
reasonable to ask them to
update kexec-tools.

  reply	other threads:[~2012-11-24 21:30 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-21  7:15 [PATCH v3 00/12] x86, boot, 64bit: Add support for loading ramdisk and bzImage high Yinghai Lu
2012-11-21  7:15 ` [PATCH v3 01/12] x86, boot: move verify_cpu.S after 0x200 Yinghai Lu
2012-11-21 17:23   ` H. Peter Anvin
2012-11-21 19:45     ` Yinghai Lu
2012-11-21 19:50       ` H. Peter Anvin
2012-11-21 20:15         ` Yinghai Lu
2012-11-22  5:48           ` Eric W. Biederman
     [not found]             ` <3178cb29-0e9e-44d2-b21f-45c53f38980a@email.android.com>
2012-11-22 11:27               ` Eric W. Biederman
2012-11-24  7:00                 ` Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 02/12] x86, boot: Move lldt/ltr out of 64bit code section Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 03/12] x86, 64bit: set extra ident page table for whole kernel range Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 04/12] x86, 64bit: add support for loading kernel above 512G Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 05/12] x86: Merge early_reserve_initrd for 32bit and 64bit Yinghai Lu
2012-11-21  7:40   ` Pekka Enberg
2012-11-21  7:16 ` [PATCH v3 06/12] x86: add get_ramdisk_image/size Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 07/12] x86, boot: add get_cmd_line_ptr() Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 08/12] x86, boot: Don't check if cmd_line_ptr is accessible in misc/decompressor() Yinghai Lu
2012-11-21 17:21   ` H. Peter Anvin
2012-11-21 19:18     ` Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 09/12] x86, boot: update cmd_line_ptr to unsigned long Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 10/12] x86: use io_remap to access real_mode_data Yinghai Lu
2012-11-21  7:16 ` [PATCH v3 11/12] x86, boot: add fields to support load bzImage and ramdisk high Yinghai Lu
2012-11-21 17:17   ` H. Peter Anvin
2012-11-21 18:59     ` Yinghai Lu
2012-11-21 19:18       ` H. Peter Anvin
2012-11-22  5:56         ` Yinghai Lu
     [not found]           ` <a1ca794a-09d4-4d36-8c8c-67100cb3696e@email.android.com>
2012-11-22  6:47             ` Yinghai Lu
2012-11-22  6:58               ` Yinghai Lu
2012-11-22 15:59                 ` H. Peter Anvin
2012-11-22 18:28                   ` Yinghai Lu
2012-11-22 18:37                     ` H. Peter Anvin
2012-11-22 18:50                       ` Yinghai Lu
2012-11-22 18:51                         ` H. Peter Anvin
2012-11-22 20:18                           ` Yinghai Lu
2012-11-22 20:20                             ` H. Peter Anvin
2012-11-22 20:29                               ` Yinghai Lu
2012-11-22 20:50                             ` H. Peter Anvin
2012-11-22 21:02                               ` H. Peter Anvin
2012-11-22 22:13                                 ` Yinghai Lu
2012-11-24 12:37                       ` Eric W. Biederman
2012-11-24 17:32                         ` H. Peter Anvin
     [not found]                           ` <CAE9FiQV0Q0fi7TrNjihdsUt0ueT4LLON4o+JEmX6ry9S6AU-ug@mail.gmail.com>
2012-11-24 18:24                             ` H. Peter Anvin
2012-11-24 19:50                           ` H. Peter Anvin
2012-11-24 21:30                             ` Yinghai Lu [this message]
2012-11-24 21:38                               ` H. Peter Anvin
2012-11-24 22:18                                 ` Yinghai Lu
2012-11-24 22:32                                   ` H. Peter Anvin
2012-11-24 23:24                                     ` Yinghai Lu
2012-11-24 23:50                             ` Eric W. Biederman
2012-11-25  0:04                               ` H. Peter Anvin
2012-11-25  0:11                                 ` Yinghai Lu
2012-11-25  5:50                                   ` Yinghai Lu
2012-11-25  5:52                                     ` H. Peter Anvin
2012-11-25  6:09                                       ` Yinghai Lu
2012-11-25  0:04                               ` Yinghai Lu
2012-11-25  0:06                                 ` H. Peter Anvin
2012-11-21  7:16 ` [PATCH v3 12/12] x86: remove 1024g limitation for kexec buffer on 64bit Yinghai Lu

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