On Tue, Mar 20, 2018 at 11:25 AM +0100, Marc Hartmayer <mhartmay@xxxxxxxxxxxxxxxxxx> wrote: > Hi, > > there is a race condition between 'qemuDomainCreate' and > 'qemuDomainDestroy' causing a NULL pointer segmentation fault when > accessing priv->monConfig. The race condition can be easily reproduced > using gdb. > > (gdb) set non-stop on > # set breakpoint on line 'mon = qemuMonitorOpen(vm, …)' > (gdb) b qemu_process.c:1799 > # Actually, this second breakpoint is optional but it’s good to see > where priv->monConfig is set to NULL > # set breakpoint on line priv->monConfig = NULL; > (gdb) b qemu_process.c:6589 > (gdb) run > # continue all threads - just for the case we hit a breakpoint already > (gdb) c -a > > Now start a domain (that is using QEMU) > > $ virsh start domain > > The first breakpoint will be hit. Now run in a second shell > > $ virsh destroy domain > > The second breakpoint will be hit. Continue the thread where the second > breakpoint was hit (for this example this is thread 4) > > (gdb) thread apply 4 continue > > Now continue the thread where the first breakpoint was hit. > > => Segmentation fault because of a NULL pointer dereference at > config->value > > Since I'm not very familiar with that part of the code, I wanted to ask > for your advice. > > Thanks in advance. > > Beste Grüße / Kind regards > Marc Hartmayer > > IBM Deutschland Research & Development GmbH > Vorsitzende des Aufsichtsrats: Martina Koederitz > Geschäftsführung: Dirk Wittkopp > Sitz der Gesellschaft: Böblingen > Registergericht: Amtsgericht Stuttgart, HRB 243294 Any ideas? --- Beste Grüße / Kind regards Marc Hartmayer IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
