From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryan Harper Subject: gdbserver-xen x86_64 paravirt guest debugging Date: Wed, 19 Apr 2006 17:09:51 -0500 Message-ID: <20060419220951.GS16776@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org I've attempted to debug live x86_64 domU domains with little success. gdbserver-xen segfaults and I've starting running gdb on gdbserver-xen to see where things are going south. I kick off the server under gdb, and then run gdb client and remote attach. This appears to succeed, and gives me: [New Thread 0] [Switching to Thread 0] 0xffffffff8014e258 in softlockup_tick (regs=0xffff880026c6fcd8) at kernel/softlockup.c:50 50 unsigned long timestamp = per_cpu(timestamp, this_cpu); But when I ask for a backtrace: (gdb) bt #0 0xffffffff8014e258 in softlockup_tick (regs=0xffff880026c6fcd8) at kernel/softlockup.c:50 Ignoring packet error, continuing... Reply contains invalid hex digit 116 On the other side (gdbserver-xen) I see: (gdb) run The program being debugged has been started already. Start it from the beginning? (y or n) y Starting program: /home/rharper/work/openhype/xen/unstable/hg/d/tools/debugger/gdb/gdb-6.2.1-linux-x86_64-xen/gdb/gdbserver/gdbserver-xen 127.0.0.1:9999 --attach 1 domain currently paused Attached; pid = 1 Listening on port 9999 Remote debugging from host 127.0.0.1 Program received signal SIGSEGV, Segmentation fault. 0x00002b2611bf410a in map_domain_va_64 (xc_handle=7, cpu=0, guest_va=0xffffffff80364ed0, perm=1) at xc_ptrace.c:295 295 l3p = page_array[l3p]; Some inspection: (gdb) p l3p $4 = 796261 (gdb) p nr_pages $5 = 196608 page_array only has 196k entries AFAICT, so this seems problematic. Anyone have x86_64 paravirt guest debugging working on latest unstable? -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx (512) 838-9253 T/L: 678-9253 ryanh@us.ibm.com