From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Hgnr4-0000Hs-IC for qemu-devel@nongnu.org; Wed, 25 Apr 2007 16:12:46 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Hgnr4-0000Hc-8Z for qemu-devel@nongnu.org; Wed, 25 Apr 2007 16:12:46 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Hgnr3-0000HZ-VK for qemu-devel@nongnu.org; Wed, 25 Apr 2007 16:12:45 -0400 Received: from fmmailgate01.web.de ([217.72.192.221]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1HgnlO-00029U-E0 for qemu-devel@nongnu.org; Wed, 25 Apr 2007 16:06:54 -0400 Message-ID: <462FB4A1.3020704@web.de> Date: Wed, 25 Apr 2007 22:05:53 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <5d649bdb0704241811s301aa41bg2a93b8b4c923b023@mail.gmail.com> <462EEF7A.5040708@web.de> <5d649bdb0704242329x587bbfc4qe9feefd037e24f60@mail.gmail.com> <462EF6D5.1040504@web.de> <5d649bdb0704250854w3b7f413jae5241e9d229011e@mail.gmail.com> <462F7D45.9000505@web.de> <5d649bdb0704251007q771d7e92o288a4ea9319ced09@mail.gmail.com> In-Reply-To: <5d649bdb0704251007q771d7e92o288a4ea9319ced09@mail.gmail.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigCAD70140422E01715541252F" Sender: jan.kiszka@web.de Subject: [Qemu-devel] Re: How to debug Linux kernel on qemu with kgdb? Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Neo Jia Cc: qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigCAD70140422E01715541252F Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Neo Jia wrote: > On 4/25/07, Jan Kiszka wrote: >> Neo Jia wrote: >> > On 4/25/07, Jan Kiszka wrote: >> >> Neo Jia wrote: >> >> > On 4/25/07, Jan Kiszka wrote: >> >> >> Neo Jia wrote: >> >> >> > hi, >> >> >> > >> >> >> > I am trying to use debug kgdb patched linux kernel on my qemu.= >> Both >> >> >> > the native and target platform are IA32. I am wondering if >> there is >> >> >> > anyone can show me the procedure? >> >> >> >> >> >> Yep, see >> >> https://mail.gna.org/public/xenomai-core/2006-09/msg00202.html >> >> >> >> >> >> (BTW, I think that kgdb bug is still unfixed - I never got a >> >> feedback.) >> >> > >> >> > I can connect gdb through /dev/pts/XX. My qemu is lanuched by >> >> > >> >> > qemu -nographic -hda linux.img -kernel >> >> > ./2.6.15.5-kgdb/vmlinuz-2.6.15.5-kgdb -serial pty -append "kgdbwa= it >> >> > console=3DttyS0 root=3D/dev/hda sb=3D0x220,5,1,5 ide2=3Dnoprobe i= de3=3Dnoprobe >> >> > ide4=3Dnoprobe ide5=3Dnoprobe" >> >> > >> >> > Do you know where can I get the console output? >> >> > >> >> >> >> Use "... -serial stdio -serial pty ..." and attached kgdb to the >> second >> >> serial port (I think to recall that is default anyway). The first >> one is >> >> then used for the kernel console. >> >> >> >> > I would like to work out kgdb + qemu to debug linux kernel. >> >> >> >> ??? So you really want to debug the kernel when kgdb is applied, ie= =2E >> >> actually debug kgdb? If you only intend to debug the kernel itself,= >> qemu >> >> -s + gdb is enough. >> > >> > Jan, >> > >> > I just would like to debug kernel itself. I have tried qemu -s + gdb= >> > but it keeps >> > getting "apic_timer_interrupt" when I am using "n" command. >> > >> > The following is the output: >> > >> >> gdb vmlinux >> > GNU gdb 6.5.50.20060621-cvs >> > Copyright (C) 2006 Free Software Foundation, Inc. >> > GDB is free software, covered by the GNU General Public License, and= >> you >> > are >> > welcome to change it and/or distribute copies of it under certain >> > conditions. >> > Type "show copying" to see the conditions. >> > There is absolutely no warranty for GDB. Type "show warranty" for >> details. >> > This GDB was configured as "i686-pc-linux-gnu"...Using host >> > libthread_db library "/lib/tls/libthread_db.so.1". >> > >> > (gdb) target remote localhost:1234 >> > Remote debugging using localhost:1234 >> > 0x0000fff0 in ?? () >> > warning: shared library handler failed to enable breakpoint >> > (gdb) c >> > Continuing. >> > >> > Program received signal SIGINT, Interrupt. >> > default_idle () at include/asm/bitops.h:252 >> > 252 return ((1UL << (nr & 31)) & (addr[nr >> 5])) !=3D 0= ; >> > (gdb) b sys_ex >> > sys_execve sys_exit sys_exit_group >> > (gdb) b sys_execve >> > Breakpoint 1 at 0xc0101ac1: file arch/i386/kernel/process.c, line 79= 1. >> > (gdb) c >> > Continuing. >> > >> > Breakpoint 1, sys_execve (regs=3D >> > {ebx =3D 135197704, ecx =3D 135197864, edx =3D 135244936, esi =3D= >> > 135197704, edi =3D 135197704, ebp =3D -1079176984, eax =3D 11, xds =3D= 123, >> > xes =3D 123, orig_eax =3D 11, eip =3D -1208835017, xcs =3D 115, efla= gs =3D 582, >> > esp =3D -1079177012, xss =3D 123}) >> > at arch/i386/kernel/process.c:791 >> > 791 filename =3D getname((char __user *) regs.ebx); >> > (gdb) n >> > 0xc0103666 in apic_timer_interrupt () at include/asm/current.h:9 >> > 9 { >> >> That's normal. You stopped the kernel in sys_execve with interrupts >> enabled. When continuing, qemu replays any pending interrupts, here th= e >> timer. Thus your next instruction is not in sys_execve, but in the >> interrupt handler. You can try finish then and hope that you will retu= rn >> to the next line in sys_execve, or you put another breakpoint at the >> next interesting spot and just issue continue. >> >> Jan >> >> >> PS: Using kgdb from inside qemu should work (at least it once did for >> me), but it is really sloooow. >> >=20 > Could you show me the procedure you did? I just want to use this to > learn kernel code. Did you redirect kgdb to ttyS1? Jan --------------enigCAD70140422E01715541252F Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGL7ShniDOoMHTA+kRArLIAJ9y78C568nZxdSZyg2RWU//HRpJhACfS6rX /yogGAEEJrXihBrHmcCZPK4= =dxI0 -----END PGP SIGNATURE----- --------------enigCAD70140422E01715541252F--