Debugging the hypervisor

Debugging the hypervisor

[Matthew Donovan]

I am trying to debug the Xen hypervisor from a second computer over the
serial port, but nothing seems to work.  Using mercurial, I got
xen-3.2-testing.hg.  I followed the steps in crashdb.txt in the docs/misc/
folder:
	set debug=y in Config.mk, crash_debug=y in xen/Rules.mk

I also added -fno-omit-frame-pointer to these file as well.

I compiled with no errors and booted with minicom connected to the
workstation via com1 but when I do Ctrl-A three times to connect, nothing
happens.  The debuggee boots find and gives me the login screen as normal.
Is there a special time to hit the Ctrl-A in minicom?  Should the kernel
wait for a connection from gdb?

I've tried various combinations of using nsplitd and a serial-split patch I
found mentioned on mailing lists and setting the boot flags to com=1H and
com=1.  Nothing seems to work.

Is the gdb stub working with this version of the code?

I have checked the serial connection by connecting minicom to the port and
from the remote machine doing the command "echo test > /dev/ttyS0" and I
receive the text.  I have minicom set for 9600 8n1 and I use the same boot
flags set in the grub config file.

What am I missing?

Thanks
-matthew

Re: Debugging the hypervisor

[Keir Fraser]

I'm rather confused about what you're trying to achieve. A good first step
would be to get Xen console output over the serial line. You achieve this by
specifying com1=115200 (for example) and console=com1,vga on Xen's command
line. If you can get that working then you can move onto the gdbstub. This
requires:
 1. that you add e.g. 'com1=115200 gdb=com1' to Xen's command line
 2. you connect to the gdbstub with gdb, not with minicom!
 3. Xen must crash for the gdbstub to be entered. The stub provides only
post-mortem debugging analysis support

 -- Keir

On 21/5/08 16:10, "Matthew Donovan" <matthew@atc-nycorp.com> wrote:

> I am trying to debug the Xen hypervisor from a second computer over the
> serial port, but nothing seems to work.  Using mercurial, I got
> xen-3.2-testing.hg.  I followed the steps in crashdb.txt in the docs/misc/
> folder:
> set debug=y in Config.mk, crash_debug=y in xen/Rules.mk
> 
> I also added -fno-omit-frame-pointer to these file as well.
> 
> I compiled with no errors and booted with minicom connected to the
> workstation via com1 but when I do Ctrl-A three times to connect, nothing
> happens.  The debuggee boots find and gives me the login screen as normal.
> Is there a special time to hit the Ctrl-A in minicom?  Should the kernel
> wait for a connection from gdb?
> 
> I've tried various combinations of using nsplitd and a serial-split patch I
> found mentioned on mailing lists and setting the boot flags to com=1H and
> com=1.  Nothing seems to work.
> 
> Is the gdb stub working with this version of the code?
> 
> I have checked the serial connection by connecting minicom to the port and
> from the remote machine doing the command "echo test > /dev/ttyS0" and I
> receive the text.  I have minicom set for 9600 8n1 and I use the same boot
> flags set in the grub config file.
> 
> What am I missing?
> 
> Thanks
> -matthew
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel

xen-unstable c/s 18846 build error

[Srinivas Maturi]

We are seeing the following build error with xen-unstable c/s 18846.

make[4]: Entering directory 
`/builddir/build/BUILD/xen-unstable/tools/ioemu-remote/i386-dm'
../xen-hooks.mak:53: *** pciutils-dev package not found - missing 
/usr/include/pci
../xen-hooks.mak:54: *** PCI passthrough capability has been disabled
../xen-hooks.mak:53: *** pciutils-dev package not found - missing 
/usr/include/pci
../xen-hooks.mak:54: *** PCI passthrough capability has been disabled
/builddir/build/BUILD/xen-unstable//tools/cross-install -d -m0755 -p 
"/var/tmp/xen-3.2.0-18846-root//usr/lib/xen/bin"
/builddir/build/BUILD/xen-unstable//tools/cross-install -d -m0755 -p 
"/var/tmp/xen-3.2.0-18846-root//etc/xen"
/builddir/build/BUILD/xen-unstable//tools/cross-install -m0755 -p 
qemu-ifup "/var/tmp/xen-3.2.0-18846-root//etc/xen/"
/builddir/build/BUILD/xen-unstable//tools/cross-install -m 755 -s 
qemu-dm "/var/tmp/xen-3.2.0-18846-root/usr/lib/xen/bin"
make[4]: Leaving directory 
`/builddir/build/BUILD/xen-unstable/tools/ioemu-remote/i386-dm'
make[3]: Leaving directory 
`/builddir/build/BUILD/xen-unstable/tools/ioemu-remote'
make[2]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools'
make[2]: Entering directory `/builddir/build/BUILD/xen-unstable/tools'
make -C xenpmd install
make[3]: Entering directory 
`/builddir/build/BUILD/xen-unstable/tools/xenpmd'
gcc -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions 
-fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 
-mtune=generic -fasynchronous-unwind-tables -O2 -fomit-frame-pointer 
-m32 -march=i686 -fno-strict-aliasing -std=gnu99 -Wall 
-Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement  -O2 
-fomit-frame-pointer -m32 -march=i686 -fno-strict-aliasing -std=gnu99 
-Wall -Wstrict-prototypes -Wno-unused-value 
-Wdeclaration-after-statement  -O2 -fomit-frame-pointer -m32 -march=i686 
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes 
-Wno-unused-value -Wdeclaration-after-statement  -D__XEN_TOOLS__ 
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE 
-D_LARGEFILE64_SOURCE -mno-tls-direct-seg-refs -O2 -fomit-frame-pointer 
-m32 -march=i686 -fno-strict-aliasing -std=gnu99 -Wall 
-Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement  
-D__XEN_TOOLS__ -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 
-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -mno-tls-direct-seg-refs -O2 
-fomit-frame-pointer -m32 -march=i686 -fno-strict-aliasing -std=gnu99 
-Wall -Wstrict-prototypes -Wno-unused-value 
-Wdeclaration-after-statement  -D__XEN_TOOLS__ -D_LARGEFILE_SOURCE 
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE 
-mno-tls-direct-seg-refs -Werror -I../../tools/xenstore 
-I../../tools/include     -L../../tools/xenstore -lxenstore  xenpmd.c   
-o xenpmd
cc1: warnings being treated as errors
xenpmd.c: In function 'write_battery_info_to_xenstore':
xenpmd.c:376: warning: call to __builtin___strncat_chk might overflow 
destination buffer
make[3]: *** [xenpmd] Error 1
make[3]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools/xenpmd'
make[2]: *** [subdir-install-xenpmd] Error 2
make[2]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools'
make[1]: *** [subdirs-install] Error 2
make[1]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools'
make: *** [install-tools] Error 2
error: Bad exit status from /var/tmp/rpm-tmp.69009 (%build)

Thanks,
Maturi

Re: xen-unstable c/s 18846 build error

[Keir Fraser]

Thanks. Fixed as c/s 18849.

 -- Keir

On 02/12/2008 20:01, "Srinivas Maturi" <srinivas.maturi@oracle.com> wrote:

> 
> We are seeing the following build error with xen-unstable c/s 18846.
> 
> make[4]: Entering directory
> `/builddir/build/BUILD/xen-unstable/tools/ioemu-remote/i386-dm'
> ../xen-hooks.mak:53: *** pciutils-dev package not found - missing
> /usr/include/pci
> ../xen-hooks.mak:54: *** PCI passthrough capability has been disabled
> ../xen-hooks.mak:53: *** pciutils-dev package not found - missing
> /usr/include/pci
> ../xen-hooks.mak:54: *** PCI passthrough capability has been disabled
> /builddir/build/BUILD/xen-unstable//tools/cross-install -d -m0755 -p
> "/var/tmp/xen-3.2.0-18846-root//usr/lib/xen/bin"
> /builddir/build/BUILD/xen-unstable//tools/cross-install -d -m0755 -p
> "/var/tmp/xen-3.2.0-18846-root//etc/xen"
> /builddir/build/BUILD/xen-unstable//tools/cross-install -m0755 -p
> qemu-ifup "/var/tmp/xen-3.2.0-18846-root//etc/xen/"
> /builddir/build/BUILD/xen-unstable//tools/cross-install -m 755 -s
> qemu-dm "/var/tmp/xen-3.2.0-18846-root/usr/lib/xen/bin"
> make[4]: Leaving directory
> `/builddir/build/BUILD/xen-unstable/tools/ioemu-remote/i386-dm'
> make[3]: Leaving directory
> `/builddir/build/BUILD/xen-unstable/tools/ioemu-remote'
> make[2]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools'
> make[2]: Entering directory `/builddir/build/BUILD/xen-unstable/tools'
> make -C xenpmd install
> make[3]: Entering directory
> `/builddir/build/BUILD/xen-unstable/tools/xenpmd'
> gcc -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
> -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386
> -mtune=generic -fasynchronous-unwind-tables -O2 -fomit-frame-pointer
> -m32 -march=i686 -fno-strict-aliasing -std=gnu99 -Wall
> -Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement  -O2
> -fomit-frame-pointer -m32 -march=i686 -fno-strict-aliasing -std=gnu99
> -Wall -Wstrict-prototypes -Wno-unused-value
> -Wdeclaration-after-statement  -O2 -fomit-frame-pointer -m32 -march=i686
> -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
> -Wno-unused-value -Wdeclaration-after-statement  -D__XEN_TOOLS__
> -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
> -D_LARGEFILE64_SOURCE -mno-tls-direct-seg-refs -O2 -fomit-frame-pointer
> -m32 -march=i686 -fno-strict-aliasing -std=gnu99 -Wall
> -Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement
> -D__XEN_TOOLS__ -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64
> -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -mno-tls-direct-seg-refs -O2
> -fomit-frame-pointer -m32 -march=i686 -fno-strict-aliasing -std=gnu99
> -Wall -Wstrict-prototypes -Wno-unused-value
> -Wdeclaration-after-statement  -D__XEN_TOOLS__ -D_LARGEFILE_SOURCE
> -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
> -mno-tls-direct-seg-refs -Werror -I../../tools/xenstore
> -I../../tools/include     -L../../tools/xenstore -lxenstore  xenpmd.c
> -o xenpmd
> cc1: warnings being treated as errors
> xenpmd.c: In function 'write_battery_info_to_xenstore':
> xenpmd.c:376: warning: call to __builtin___strncat_chk might overflow
> destination buffer
> make[3]: *** [xenpmd] Error 1
> make[3]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools/xenpmd'
> make[2]: *** [subdir-install-xenpmd] Error 2
> make[2]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools'
> make[1]: *** [subdirs-install] Error 2
> make[1]: Leaving directory `/builddir/build/BUILD/xen-unstable/tools'
> make: *** [install-tools] Error 2
> error: Bad exit status from /var/tmp/rpm-tmp.69009 (%build)
> 
> Thanks,
> Maturi
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel