linux-kernel - Re: 2.6.19-rc1: kexec broken on x86

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Message-ID: <20061005142400.GC20551@in.ibm.com>
Date:	Thu, 5 Oct 2006 10:24:00 -0400
From:	Vivek Goyal <vgoyal@...ibm.com>
To:	Magnus Damm <magnus.damm@...il.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	fastboot@...ts.osdl.org,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Horms <horms@...ge.net.au>, Magnus Damm <magnus@...inux.co.jp>,
	Andi Kleen <ak@....de>
Subject: Re: 2.6.19-rc1: kexec broken on x86_64

On Thu, Oct 05, 2006 at 10:56:51PM +0900, Magnus Damm wrote:
> Hi Vivek,
> 
> On 10/5/06, Vivek Goyal <vgoyal@...ibm.com> wrote:
> >On Thu, Oct 05, 2006 at 07:28:35PM +0900, Magnus Damm wrote:
> >> Kexec is broken on x86_64 under 2.6.19-rc1.
> >>
> >> Or rather - kexec works ok under 2.6.19-rc1, but something related to
> >> the vmlinux format has probably changed and kexec-tools fails to load
> >> a vmlinux from 2.6.19-rc1.
> >>
> >> Loading bzImage works as usual, but vmlinux does not load properly.
> >>
> >> The kexec binary fails with the following message:
> >>
> >> Overlapping memory segments at 0x351000
> >> sort_segments failed
> >> / #
> >>
> >
> >Hi Magnus,
> >
> >Can you please post the readelf -l output of the vmlinux you are trying
> >to load. That's will give some indication if the segments are really
> >overlapping in vmlinux or is it some processing bug at kexec-tools part.
> 
> Elf file type is EXEC (Executable file)
> Entry point 0x100100
> There are 4 program headers, starting at offset 64
> 
> Program Headers:
>  Type           Offset             VirtAddr           PhysAddr
>                 FileSiz            MemSiz              Flags  Align
>  LOAD           0x0000000000100000 0xffffffff80100000 0x0000000000100000
>                 0x00000000001a4888 0x00000000001a4888  R E    100000
>  LOAD           0x00000000002a5000 0xffffffff802a5000 0x00000000002a5000
>                 0x000000000008e086 0x00000000000c1504  RWE    100000
>  LOAD           0x0000000000400000 0xffffffffff600000 0x00000000002fd000
>                 0x0000000000000c08 0x0000000000000c08  RWE    100000
>  NOTE           0x0000000000000000 0x0000000000000000 0x0000000000000000
>                 0x0000000000000000 0x0000000000000000  R      8
> 
> Section to Segment mapping:
>  Segment Sections...
>   00     .text __ex_table .rodata .pci_fixup __ksymtab __ksymtab_gpl
> __ksymtab_unused __ksymtab_strings __param
>   01     .data .data.cacheline_aligned .data.read_mostly
> .data.init_task .data.page_aligned .init.text .init.data .init.setup
> .initcall.init .con_initcall.init .altinstructions
> .altinstr_replacement .exit.text .init.ramfs .bss
>   02     .vsyscall_0 .xtime_lock .vxtime .vgetcpu_mode .sys_tz
> .sysctl_vsyscall .xtime .jiffies .vsyscall_1 .vsyscall_2 .vsyscall_3
>   03
> 

Ok. So second and third program header are overlapping in physical
address space and that's why kexec-tools is cribbing.

Looking at these headers, it looks like program header 02 which contains
will overwrite some of the data of program header 01 and I think that's
wrong. Will look more into it.

Thanks
Vivek
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