On 03/21/2013 05:53 AM, Han wrote: > Hi Richard, > > I hit other issues after moving to a recent kernel UML (i.e. cannot > fully bring up the UML). Now I am back and trying to debug UML > itself. However, when I started GDB with UML, I would hit a crash > like the following. > > I was wondering if I used the GDB in wrong way. I couldn't find > detailed info about GDB UML kernel. Any pointers? Note, this is host > GDB x86_64, the UML kernel is built as 32-bit (SUBARCH=i386). Is > that a problem? http://uml.devloop.org.uk/faq.html#gdb handle SIGSEGV pass nostop noprint
Antoine > > host#/usr/bin/gdb ./linux > GNU gdb (GDB) Red Hat Enterprise Linux (7.0.1-32.el5_6.2) > Copyright (C) 2009 Free Software Foundation, Inc. > License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> > This is free software: you are free to change and redistribute it. > There is NO WARRANTY, to the extent permitted by law. Type "show copying" > and "show warranty" for details. > This GDB was configured as "x86_64-redhat-linux-gnu". > For bug reporting instructions, please see: > <http://www.gnu.org/software/gdb/bugs/>... > Reading symbols from linux...(no debugging symbols found)...done. > (gdb) run mem=128M ubda=cow1,Debian-Squeeze-x86-root_fs umid=debian1 > Starting program: linux mem=128M ubda=cow1,Debian-Squeeze-x86-root_fs > umid=debian1 > Locating the bottom of the address space ... > Program received signal SIGSEGV, Segmentation fault. > 0x080662fb in page_ok (page=<value optimized out>) at > arch/um/os-Linux/sys-i386/task_size.c:31 > 31 n = *address; > (gdb) bt > #0 0x080662fb in page_ok (page=<value optimized out>) at > arch/um/os-Linux/sys-i386/task_size.c:31 > #1 0x08066403 in os_get_top_address () at > arch/um/os-Linux/sys-i386/task_size.c:100 > #2 0x0804a271 in linux_main (argc=4, argv=0xffff8ac4) at > arch/um/kernel/um_arch.c:277 > #3 0x0804ad3d in main (argc=4, argv=0xffff8ac4, envp=0xffff8ad8) at > arch/um/os-Linux/main.c:150 > (gdb) > > > On Fri, Mar 15, 2013 at 11:36 AM, Han <keepsim...@gmail.com> wrote: >> On Fri, Mar 15, 2013 at 11:11 AM, Han <keepsim...@gmail.com> wrote: >>> On Fri, Mar 15, 2013 at 10:50 AM, richard -rw- weinberger >>> <richard.weinber...@gmail.com> wrote: >>>> On Fri, Mar 15, 2013 at 6:01 PM, Han <keepsim...@gmail.com> wrote: >>>>> I started UML with "mem=128M", the module init only kmalloc 8 bytes: >>>>> >>>>> kmalloc(size, GFP_KERNEL); >>>>> >>>>> where "size" is 8. >>>> >>>> This has to work. Just in case, please retry with a more recent kernel. >>> >>> I will retry to a more recent kernel. On another front, I suspect >>> that I might be using incorrect compiling/linking for the module. >>> Because of certain constraints, I was modifying the build command from >>> existing builds of the module code. The existing build were for x86 >>> linux, and I modified them to use x86 UML. >>> >>> I modified the options for "gcc", and I think the compile is ok. But >>> I did not modify "ld" command. Is there anything I should do for >>> "ld" making sure linking was ok for the UML ? Here is example of my >>> current ld: >>> >>> /usr/bin/ld -nostdlib -m elf_i386 -r -o <my_uml_module_name> >>> <my_c_obj1> <my_c_obj2> >>> >>> the "ld" was successful but now I suspect it was only for the host, >>> not good for UML. Note: my host linux uses different kernel version >>> from the UML tree. The host kernel version is 2.6.18. >> >> Btw, the UML kernel Changes file states the following requirements: >> >> o Gnu C 3.2 # gcc --version >> o Gnu make 3.79.1 # make --version >> o binutils 2.12 # ld -v >> >> and I am using the following versions: >> >> gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-50) >> GNU Make 3.80 >> GNU ld version 2.17.50.0.6-14.el5 20061020 >> >> Thanks >> Han >> >>> >>> Thanks >>> Han >>> >>>> >>>> -- >>>> Thanks, >>>> //richard > > ------------------------------------------------------------------------------ > Everyone hates slow websites. So do we. > Make your web apps faster with AppDynamics > Download AppDynamics Lite for free today: > http://p.sf.net/sfu/appdyn_d2d_mar > _______________________________________________ > User-mode-linux-user mailing list > User-mode-linux-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user > ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_mar _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
