From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <326364c20807010702w6ebcb4e9m79d9cb16de1ffd83@mail.gmail.com> Date: Tue, 1 Jul 2008 10:02:25 -0400 From: "Tom Lieber" To: "Russ Cox" Subject: Re: [9fans] tip 9vx segfault on Ubuntu in Xen Cc: 9fans@9fans.net In-Reply-To: <20080701125833.8AD771E8C45@holo.morphisms.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <326364c20806301953k7fa2ebf9i1c7f3049a210bf39@mail.gmail.com> <20080701125833.8AD771E8C45@holo.morphisms.net> Topicbox-Message-UUID: d2e23804-ead3-11e9-9d60-3106f5b1d025 On Tue, Jul 1, 2008 at 9:00 AM, Russ Cox wrote: >> I have Ubuntu on a VPS (on Xen) and I'd like to install a Plan 9 >> server using 9vx. 9vx tip compiles, but segfaults after the "256M >> memory" line (as does the precompiled binary, in the same place). I am >> tunneling to local X11 on OS X 10.5.3. >> >> I don't know how to debug this properly, but here is gdb output >> similar to what I saw in another report. > > The seg faults are normal. 9vx handles them and continues. > To run under gdb you need to say > > handle SIGSEGV noprint nostop > > so that gdb will let it keep going. > > What behavior did you see when you weren't running under gdb? > If it was a panic, better to set a break point at panic. No panic: the window appears and two lines print (the command-line arguments and the memory readout), then everything stops. When I use -X, the lines of assembly stop. This looks useless, but if I pause in gdb the backtrace is: #0 0xffffe410 in __kernel_vsyscall () #1 0x401f6647 in poll () from /lib/tls/i686/cmov/libc.so.6 #2 0x40061839 in ?? () from /usr/lib/libX11.so.6 #3 0x08272970 in ?? () #4 0x00000001 in ?? () #5 0xffffffff in ?? () #6 0x40111b2c in ?? () from /usr/lib/libX11.so.6 #7 0x082723c0 in ?? () #8 0x40111b2c in ?? () from /usr/lib/libX11.so.6 #9 0x082723c0 in ?? () #10 0x00000000 in ?? () If I press keys, though, I get output like this, so I guess it's not completely frozen: memdraw 827b780 [4 57] [13 68] 8269da8 [1879113727 -613566757] 8269e60 [918 2] memdraw 827b780 [13 57] [22 68] 8269da8 [1879113727 -613566757] 8269e60 [918 2] memdraw 827b780 [22 60] [31 68] 8269da8 [1879113727 -613566757] 8269e60 [873 5] It never does anything as long as I wait, though. -- Tom Lieber http://AllTom.com/