On Fri, Mar 02, 2018 at 10:30:57AM -0500, Farhan Ali wrote: > > > On 03/02/2018 04:23 AM, Stefan Hajnoczi wrote: > > On Thu, Mar 01, 2018 at 09:33:35AM -0500, Farhan Ali wrote: > > > Hi, > > > > > > I have been noticing some segfaults for QEMU on s390x, and I have been > > > hitting this issue quite reliably (at least once in 10 runs of a test > > > case). > > > The qemu version is 2.11.50, and I have systemd created coredumps > > > when this happens. > > > > > > Here is a back trace of the segfaulting thread: > > The backtrace looks normal. > > > > Please post the QEMU command-line and the details of the segfault (which > > memory access faulted?). > > > > > I was able to create another crash today and here is the qemu comand line > > /usr/bin/qemu-kvm -name guest=sles,debug-threads=on \ > -S -object > secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-2-sles/master-key.aes > \ > -machine s390-ccw-virtio-2.12,accel=kvm,usb=off,dump-guest-core=off \ > -m 4096 -realtime mlock=off -smp 8,sockets=8,cores=1,threads=1 \ > -object iothread,id=iothread1 -object iothread,id=iothread2 -uuid > b83a596b-3a1a-4ac9-9f3e-d9a4032ee52c \ > -display none -no-user-config -nodefaults -chardev > socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-2-sles/monitor.sock,server,nowait > > -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown > \ > -boot strict=on -drive > file=/dev/mapper/360050763998b0883980000002400002b,format=raw,if=none,id=drive-virtio-disk0,cache=none,aio=native > -device > virtio-blk-ccw,iothread=iothread1,scsi=off,devno=fe.0.0001,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 > -drive > file=/dev/mapper/360050763998b0883980000002800002f,format=raw,if=none,id=drive-virtio-disk1,cache=none,aio=native > -device > virtio-blk-ccw,iothread=iothread2,scsi=off,devno=fe.0.0002,drive=drive-virtio-disk1,id=virtio-disk1 > -netdev tap,fd=24,id=hostnet0,vhost=on,vhostfd=26 -device > virtio-net-ccw,netdev=hostnet0,id=net0,mac=02:38:a6:36:e8:1f,devno=fe.0.0000 > -chardev pty,id=charconsole0 -device > sclpconsole,chardev=charconsole0,id=console0 -device > virtio-balloon-ccw,id=balloon0,devno=fe.3.ffba -msg timestamp=on > > > This the latest back trace on the segfaulting thread, and it seems to > segfault in swapcontext. > > Program terminated with signal SIGSEGV, Segmentation fault. > #0 0x000003ff8595202c in swapcontext () from /lib64/libc.so.6
Please include the following gdb output: (gdb) disas swapcontext (gdb) i r That way it's possible to see which instruction faulted and which registers were being accessed. > This is the remaining back trace: > > #0 0x000003ff8595202c in swapcontext () from /lib64/libc.so.6 > #1 0x000002aa33b45566 in qemu_coroutine_new () at > util/coroutine-ucontext.c:164 > #2 0x000002aa33b43eac in qemu_coroutine_create > (entry=entry@entry=0x2aa33a94c98 <blk_aio_write_entry>, > opaque=opaque@entry=0x3ff74018be0) at util/qemu-coroutine.c:76 > #3 0x000002aa33a954da in blk_aio_prwv (blk=0x2aa4f0efda0, offset=<optimized > out>, bytes=<optimized out>, qiov=0x3ff74019080, > co_entry=co_entry@entry=0x2aa33a94c98 <blk_aio_write_entry>, flags=0, > cb=0x2aa338c62e8 <virtio_blk_rw_complete>, opaque=0x3ff74019020) at > block/block-backend.c:1299 > #4 0x000002aa33a9563e in blk_aio_pwritev (blk=<optimized out>, > offset=<optimized out>, qiov=<optimized out>, flags=<optimized out>, > cb=<optimized out>, opaque=0x3ff74019020) at block/block-backend.c:1400 > #5 0x000002aa338c6a38 in submit_requests (niov=<optimized out>, num_reqs=1, > start=<optimized out>, mrb=0x3ff831fe6e0, blk=<optimized out>) at > /usr/src/debug/qemu-2.11.50/hw/block/virtio-blk.c:369 > #6 virtio_blk_submit_multireq (blk=<optimized out>, > mrb=mrb@entry=0x3ff831fe6e0) at > /usr/src/debug/qemu-2.11.50/hw/block/virtio-blk.c:426 > #7 0x000002aa338c7b78 in virtio_blk_handle_vq (s=0x2aa4f2507c8, > vq=0x3ff869df010) at /usr/src/debug/qemu-2.11.50/hw/block/virtio-blk.c:620 > #8 0x000002aa338ebdf2 in virtio_queue_notify_aio_vq (vq=0x3ff869df010) at > /usr/src/debug/qemu-2.11.50/hw/virtio/virtio.c:1515 > #9 0x000002aa33b2df46 in aio_dispatch_handlers > (ctx=ctx@entry=0x2aa4f0ca050) at util/aio-posix.c:406 > #10 0x000002aa33b2eb50 in aio_poll (ctx=0x2aa4f0ca050, > blocking=blocking@entry=true) at util/aio-posix.c:692 > #11 0x000002aa33957f6a in iothread_run (opaque=0x2aa4f0c9630) at > iothread.c:60 > #12 0x000003ff86987e82 in start_thread () from /lib64/libpthread.so.0 > #13 0x000003ff85a11596 in thread_start () from /lib64/libc.so.6 > Backtrace stopped: previous frame identical to this frame (corrupt stack?) >
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