On Fri, Aug 9, 2013 at 10:43 PM, Richard W.M. Jones <rjo...@redhat.com> wrote: > Today I wrote some patches (for libguestfs) which add an experimental > UML backend: > > https://www.redhat.com/archives/libguestfs/2013-August/msg00005.html > > There are some observations from this. > > * 'ubd<N>=cow,original' is not parsed correctly. This was reported a > while back and I'm seeing the same thing with the latest kernel from > git: > > http://thread.gmane.org/gmane.linux.uml.devel/13556 > > If I have some time I'll have a go at fixing this since it seems like > a simple regression.
Patches are very welcome! > * I'm trying to use a serial port to communicate between guest and > host, using ssl3=fd:<N>. This causes the Linux process to crash soon > (but not immediately) after the guest has opened /dev/ttyS3: > > spurious interrupt in ubd_handler, err = -4 > > I've put the full call trace at the end of the email because it's > quite long[1]. This was also reported before, although the suggested > patch did not fix it: > > http://marc.info/?l=linux-kernel&m=123242364211797&w=2 > > I wonder if anyone has used the fd:<N> option in anger? I will try > using a Unix domain socket and see if it makes a difference. Hmmm. I *should* work. Which fd are you using? Can you also try pts? > * UML is pretty fast! It's certainly faster (by a factor of > 5) than > spinning up a lightweight KVM VM. Wow! Does it only boot faster or is it also faster with reading data from a filesystem? Maybe it's time to exhume the libLinux project (UML as a normal userspace library). http://user-mode-linux.sourceforge.net/old/projects.html Thanks, //richard > Rich. > > [1] Call trace > > spurious interrupt in ubd_handler, err = -4 > > Modules linked in: > Pid: 1614169860, comm: Not tainted 3.11.0-rc4-00103-g6c2580c > RIP: 0033:[<000000006001db74>] Can you please decode that address using addr2line? > RSP: 0000000080ca9f98 EFLAGS: 00010206 > RAX: 0000000000000008 RBX: 0000000000000008 RCX: 0000003f2cae6970 > RDX: 0000000000000000 RSI: 0000000080ca9fb0 RDI: 0000000000000005 > RBP: 0000000080ca9fe8 R08: 0000000080ca9ed8 R09: 0000000080ca9e40 > R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000001000 > R13: 0000000080e867c4 R14: 0000000000000001 R15: 68c00000000080ea > Call Trace: > 80ca9538: [<600151ac>]------------[ cut here ]------------ > WARNING: CPU: 0 PID: 6 at block/blk.h:210 > generic_make_request_checks+0x1aa/0x234() > BUG: recent printk recursion! > 80ca9648: [<60022207>] sig_handler_common+0x8c/0xa2 > 80ca96d0: [<6001db74>] io_thread+0x63/0x243 > 80ca9988: [<600222c2>] sig_handler+0x2e/0x39 > 80ca99a8: [<60021f33>] hard_handler+0x83/0xab > 80ca9aa8: [<6001db74>] io_thread+0x63/0x243 > 80ca9d88: [<60021eb0>] hard_handler+0x0/0xab > 80ca9f70: [<60020308>] os_seek_file+0x11/0x27 > 80ca9f80: [<6002032a>] os_read_file+0xc/0x1f > 80ca9f90: [<6001db3b>] io_thread+0x2a/0x243 > > Kernel panic - not syncing: Segfault with no mm > CPU: 0 PID: 1614169860 Comm: Not tainted 3.11.0-rc4-00103-g6c2580c #3 > > Modules linked in: > Pid: 1614169860, comm: Not tainted 3.11.0-rc4-00103-g6c2580c > RIP: 0033:[<0000000060026715>] Ditto. > RSP: 0000000080ca9328 EFLAGS: 00010246 > RAX: 0000000080ca9398 RBX: 00000000602d2460 RCX: 0000000080ca8000 > RDX: 0000000000000008 RSI: 636f6c6e6f6e5f88 RDI: 0000000080ca9398 > RBP: 0000000080ca9350 R08: 636f6c6e6f6e5f70 R09: 636f6c6e6f6e5f70 > R10: 0000003f2ca892da R11: 0000003f2ca892da R12: 000000006026b27c > R13: 000000006001db74 R14: 0000000000000004 R15: 0000000000000000 > Call Trace: > 80ca88b8: [<600151ac>] segv+0x66/0x241 > 80ca8988: [<600153e9>] segv_handler+0x62/0x6c > 80ca89c8: [<60022207>] sig_handler_common+0x8c/0xa2 > 80ca89e0: [<6001db74>] io_thread+0x63/0x243 > 80ca8a50: [<60026715>] memcpy+0xb5/0x140 > 80ca8d08: [<600222c2>] sig_handler+0x2e/0x39 > 80ca8d28: [<60021f33>] hard_handler+0x83/0xab > 80ca8d58: [<6001db74>] io_thread+0x63/0x243 > 80ca8dd0: [<6001db74>] io_thread+0x63/0x243 > 80ca8e28: [<60026715>] memcpy+0xb5/0x140 > 80ca90e8: [<60017226>] generic_write+0xf/0x38 > 80ca9108: [<600172f9>] generic_console_write+0x3e/0x165 > 80ca9288: [<6004c396>] vprintk_emit+0x2dd/0x2ee > 80ca92d8: [<6001db74>] io_thread+0x63/0x243 > 80ca92f8: [<601edf38>] printk+0x97/0x99 > 80ca9308: [<60015eff>] copy_from_user+0x36/0x8a > 80ca9328: [<60015eff>] copy_from_user+0x36/0x8a > 80ca9358: [<600699d4>] __probe_kernel_read+0x3c/0x6d > 80ca9368: [<6003f2ac>] probe_kthread_data+0x29/0x2f > 80ca9388: [<6003becc>] print_worker_info+0x66/0x124 > 80ca93f8: [<6004d204>] dump_stack_print_info+0xa6/0xaf > 80ca9428: [<601efbeb>] dump_stack+0xe/0x19 > 80ca9438: [<601ed8b7>] panic+0xf7/0x1e4 > 80ca9490: [<60056982>] __module_text_address+0xd/0x4d > 80ca94a8: [<6005a007>] is_module_text_address+0x9/0x11 > 80ca94b8: [<6003cd40>] __kernel_text_address+0x26/0x49 > 80ca94d8: [<60014146>] show_trace+0x8e/0x95 > 80ca9508: [<60026491>] show_regs+0x27/0x2a > 80ca9520: [<6001db74>] io_thread+0x63/0x243 > 80ca9538: [<6001524f>] segv+0x109/0x241 > 80ca9608: [<600153e9>] segv_handler+0x62/0x6c > 80ca9628: [<60022169>] unblock_signals+0x4a/0x5c > 80ca9648: [<60022207>] sig_handler_common+0x8c/0xa2 > 80ca96d0: [<6001db74>] io_thread+0x63/0x243 > 80ca9988: [<600222c2>] sig_handler+0x2e/0x39 > 80ca99a8: [<60021f33>] hard_handler+0x83/0xab > 80ca9aa8: [<6001db74>] io_thread+0x63/0x243 > 80ca9d88: [<60021eb0>] hard_handler+0x0/0xab > 80ca9f70: [<60020308>] os_seek_file+0x11/0x27 > 80ca9f80: [<6002032a>] os_read_file+0xc/0x1f > 80ca9f90: [<6001db3b>] io_thread+0x2a/0x243 > > Kernel panic - not syncing: Segfault with no mm > > Modules linked in: > Pid: 1614169860, comm: Not tainted 3.11.0-rc4-00103-g6c2580c > RIP: 0000:[<000001a400000004>] > RSP: 0000000000000000 EFLAGS: 6002e720 > RAX: 000000006002e770 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000602706ae > RBP: 0000000000000000 R08: 0000000000000000 R09: 000001a400000004 > R10: 00000000602d04ac R11: 000000006027069b R12: 0000000000000000 > R13: 000000006002e720 R14: 0000000000000000 R15: 000001a400000004 > Call Trace: > 80ca8748: [<6001564c>] panic_exit+0x2b/0x41 > 80ca8758: [<6015a3ac>] vsnprintf+0xd0/0x431 > 80ca8768: [<600427c7>] notifier_call_chain+0x39/0x5c > 80ca8790: [<60026715>] memcpy+0xb5/0x140 > 80ca87a8: [<60042804>] atomic_notifier_call_chain+0xf/0x11 > 80ca87b8: [<601ed8d2>] panic+0x112/0x1e4 > 80ca8810: [<60056982>] __module_text_address+0xd/0x4d > 80ca8828: [<6005a007>] is_module_text_address+0x9/0x11 > 80ca8838: [<6003cd40>] __kernel_text_address+0x26/0x49 > 80ca8858: [<60014146>] show_trace+0x8e/0x95 > 80ca8888: [<60026491>] show_regs+0x27/0x2a > 80ca88a0: [<60026715>] memcpy+0xb5/0x140 > 80ca88b8: [<6001524f>] segv+0x109/0x241 > 80ca8988: [<600153e9>] segv_handler+0x62/0x6c > 80ca89c8: [<60022207>] sig_handler_common+0x8c/0xa2 > 80ca89e0: [<6001db74>] io_thread+0x63/0x243 > > -- > Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones > virt-p2v converts physical machines to virtual machines. Boot with a > live CD or over the network (PXE) and turn machines into KVM guests. > http://libguestfs.org/virt-v2v > > ------------------------------------------------------------------------------ > Get 100% visibility into Java/.NET code with AppDynamics Lite! > It's a free troubleshooting tool designed for production. > Get down to code-level detail for bottlenecks, with <2% overhead. > Download for free and get started troubleshooting in minutes. > http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk > _______________________________________________ > User-mode-linux-devel mailing list > User-mode-linux-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel -- Thanks, //richard ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
