Re: Bad core files with 2.6.19-rc2

From: Petr Vandrovec
Date: Sun Oct 15 2006 - 15:25:07 EST


Adrian Bunk wrote:
On Sun, Oct 15, 2006 at 12:53:41PM +1000, Steve Youngs wrote:


gdb doesn't like any core dump file generated while running
2.6.19-rc2. If I `kill -SIGSEGV $some_app_pid' and then...

gdb some_app core

I get...

warning: Couldn't find general-purpose registers in core file.
#0 0x00000000 in ?? ()

But if I gdb attach to a running process and then kill -SIGSEGV
the process, it produces a normal trace without problem.


It seems this issue should be fixed in Linus' tree now.

Can you confirm it's fixed?

It should be fixed now (i.e. 26 minutes ago). Before my first fix core dump contained only some phdrs and notes, nothing else. After first fix core dump contained everything, but pieces after notes were shifted down by couple of bytes. After second fix I believe that cores are written out correctly - readelf still says that there is some zeroed note, but it seems to me like feature - older core files have this as well:

$ readelf -a core
...
Notes at offset 0x00035608 with length 0x00000018:
Owner Data size Description
Linux 0x00000004 Unknown note type: (0x00000000)

Petr Vandrovec
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