From 5651743c908d8c3b1ff0192ce9543a502ec7a206 Mon Sep 17 00:00:00 2001 From: Anthony Xu Date: Tue, 9 May 2017 15:37:12 -0700 Subject: trace: add sanity check If trace backend is set to TRACE_NOP, trace_get_vcpu_event_count returns 0, cause bitmap_new call abort. The abort can be triggered as follows: $ ./configure --enable-trace-backend=nop --target-list=x86_64-softmmu $ gdb ./x86_64-softmmu/qemu-system-x86_64 -M q35,accel=kvm -m 1G (gdb) bt #0 0x00007ffff04e25f7 in raise () from /lib64/libc.so.6 #1 0x00007ffff04e3ce8 in abort () from /lib64/libc.so.6 #2 0x00005555559de905 in bitmap_new (nbits=) at /home/root/git/qemu2.git/include/qemu/bitmap.h:96 #3 cpu_common_initfn (obj=0x555556621d30) at qom/cpu.c:399 #4 0x0000555555a11869 in object_init_with_type (obj=0x555556621d30, ti=0x55555656bbb0) at qom/object.c:341 #5 0x0000555555a11869 in object_init_with_type (obj=0x555556621d30, ti=0x55555656bd30) at qom/object.c:341 #6 0x0000555555a11efc in object_initialize_with_type (data=data@entry=0x555556621d30, size=76560, type=type@entry=0x55555656bd30) at qom/object.c:376 #7 0x0000555555a12061 in object_new_with_type (type=0x55555656bd30) at qom/object.c:484 #8 0x0000555555a121c5 in object_new (typename=typename@entry=0x555556550340 "qemu64-x86_64-cpu") at qom/object.c:494 #9 0x00005555557f6e3d in pc_new_cpu (typename=typename@entry=0x555556550340 "qemu64-x86_64-cpu", apic_id=0, errp=errp@entry=0x5555565391b0 ) at /home/root/git/qemu2.git/hw/i386/pc.c:1101 #10 0x00005555557fa33e in pc_cpus_init (pcms=pcms@entry=0x5555565f9690) at /home/root/git/qemu2.git/hw/i386/pc.c:1184 #11 0x00005555557fe0f6 in pc_q35_init (machine=0x5555565f9690) at /home/root/git/qemu2.git/hw/i386/pc_q35.c:121 #12 0x000055555574fbad in main (argc=, argv=, envp=) at vl.c:4562 Signed-off-by: Anthony Xu Message-id: 1494369432-15418-1-git-send-email-anthony.xu@intel.com Signed-off-by: Stefan Hajnoczi --- qom/cpu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'qom') diff --git a/qom/cpu.c b/qom/cpu.c index f02e9c0fae..f9111a02ba 100644 --- a/qom/cpu.c +++ b/qom/cpu.c @@ -382,6 +382,7 @@ static void cpu_common_unrealizefn(DeviceState *dev, Error **errp) static void cpu_common_initfn(Object *obj) { + uint32_t count; CPUState *cpu = CPU(obj); CPUClass *cc = CPU_GET_CLASS(obj); @@ -396,7 +397,10 @@ static void cpu_common_initfn(Object *obj) QTAILQ_INIT(&cpu->breakpoints); QTAILQ_INIT(&cpu->watchpoints); - cpu->trace_dstate = bitmap_new(trace_get_vcpu_event_count()); + count = trace_get_vcpu_event_count(); + if (count) { + cpu->trace_dstate = bitmap_new(count); + } cpu_exec_initfn(cpu); } -- cgit v1.2.1