[PATCH][V2] vmcore-dmesg: Determine correct machine pointer size
horms at verge.net.au
Wed Nov 14 18:19:18 EST 2012
On Wed, Nov 14, 2012 at 03:38:43PM +0800, Dave Young wrote:
> On 11/14/2012 12:38 AM, Vivek Goyal wrote:
> > A 32bit arch can prepare ELF64 headers. For example for PAE case to
> > preresent file offsets 64bit but data size at the offset still remains
> > 32bit. If we just base our decision based on EI_CLASS, then we will try
> > to read 64bit data from file and can run into various issues.
> > We ran into following issue when we tried to run vmcore-dmesg on a 32bit
> > PAE system vmcore which had 64bit elf headers.
> > No program header covering vaddr 0xc0a6a688c0b89100found kexec bug?
> > Basically we try to read value of log_buf variable from address
> > log_buf_vaddr. We read in 64bit value and then pass that value again
> > to vaddr_to_offset() in an attempt to get to actual log_buf start
> > and get error message.
> > So determine the machine pointer size based on ELF class and arch and read
> > the bytes from file accordingly.
> > v2: Fixed the code as per suggestion from Eric.
> > Signed-off-by: Vivek Goyal <vgoyal at redhat.com>
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