Hi, Thanos, On Mon, Jul 19, 2021 at 02:38:52PM +0000, Thanos Makatos wrote: > I can trivially trigger an assertion with a build where I merged the recent > vfio-user patches > (https://patchew.org/QEMU/cover.1626675354.git.elena.ufimts...@oracle.com/) > to master and then merging the result into your xzpeter/memory-sanity branch, > I've pushed the branch here: > https://github.com/tmakatos/qemu/tree/memory-sanity. I explain the repro > steps below in case you want to take a look: > > Build as follows: > > ./configure --prefix=/opt/qemu-xzpeter --target-list=x86_64-softmmu > --enable-kvm --enable-debug --enable-multiprocess && make -j `nproc` && make > install > > Then build and run the GPIO sample from libvfio-user > (https://github.com/nutanix/libvfio-user): > > libvfio-user/build/dbg/samples/gpio-pci-idio-16 -v /var/run/vfio-user.sock > > And then run QEMU as follows: > > gdb --args /opt/qemu-xzpeter/bin/qemu-system-x86_64 -cpu host -enable-kvm > -smp 4 -m 2G -object > memory-backend-file,id=mem0,size=2G,mem-path=/dev/hugepages,share=on,prealloc=yes > -numa node,memdev=mem0 -kernel bionic-server-cloudimg-amd64-vmlinuz-generic > -initrd bionic-server-cloudimg-amd64-initrd-generic -append 'console=ttyS0 > root=/dev/sda1 single' -hda bionic-server-cloudimg-amd64-0.raw -nic > user,model=virtio-net-pci -machine pc-q35-3.1 -device > vfio-user-pci,socket=/var/run/vfio-user.sock -nographic > > I immediately get the following stack trace: > > Thread 5 "qemu-system-x86" received signal SIGUSR1, User defined signal 1.
This is SIGUSR1. QEMU uses it for general vcpu ipis. > [Switching to Thread 0x7fffe6e82700 (LWP 151973)] > __lll_lock_wait () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:103 > 103 ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: No such file or > directory. > (gdb) bt > #0 0x00007ffff655d29c in __lll_lock_wait () at > ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:103 > #1 0x00007ffff6558642 in __pthread_mutex_cond_lock > (mutex=mutex@entry=0x5555568bb280 <qemu_global_mutex>) at > ../nptl/pthread_mutex_lock.c:80 > #2 0x00007ffff6559ef8 in __pthread_cond_wait_common (abstime=0x0, > mutex=0x5555568bb280 <qemu_global_mutex>, cond=0x555556cecc30) at > pthread_cond_wait.c:645 > #3 0x00007ffff6559ef8 in __pthread_cond_wait (cond=0x555556cecc30, > mutex=0x5555568bb280 <qemu_global_mutex>) at pthread_cond_wait.c:655 > #4 0x000055555604f717 in qemu_cond_wait_impl (cond=0x555556cecc30, > mutex=0x5555568bb280 <qemu_global_mutex>, file=0x5555561ca869 > "../softmmu/cpus.c", line=514) at ../util/qemu-thread-posix.c:194 > #5 0x0000555555d28a4a in qemu_cond_wait_iothread (cond=0x555556cecc30) at > ../softmmu/cpus.c:514 > #6 0x0000555555d28781 in qemu_wait_io_event (cpu=0x555556ce02c0) at > ../softmmu/cpus.c:425 > #7 0x0000555555e5da75 in kvm_vcpu_thread_fn (arg=0x555556ce02c0) at > ../accel/kvm/kvm-accel-ops.c:54 > #8 0x000055555604feed in qemu_thread_start (args=0x555556cecc70) at > ../util/qemu-thread-posix.c:541 > #9 0x00007ffff6553fa3 in start_thread (arg=<optimized out>) at > pthread_create.c:486 > #10 0x00007ffff64824cf in clone () at > ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 Would you please add below to your ~/.gdbinit script? handle SIGUSR1 nostop noprint Or just run without gdb and wait it to crash with SIGABRT. Thanks, -- Peter Xu
