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[Qemu-devel] [PULL for-2.9 1/1] trace: add sanity check
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL for-2.9 1/1] trace: add sanity check |
Date: |
Fri, 12 May 2017 10:38:12 -0400 |
From: Anthony Xu <address@hidden>
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=<optimized out>)
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 (address@hidden,
size=76560,
address@hidden) at qom/object.c:376
#7 0x0000555555a12061 in object_new_with_type (type=0x55555656bd30) at
qom/object.c:484
#8 0x0000555555a121c5 in object_new (address@hidden "qemu64-x86_64-cpu")
at qom/object.c:494
#9 0x00005555557f6e3d in pc_new_cpu (address@hidden "qemu64-x86_64-cpu",
apic_id=0,
address@hidden <error_fatal>) at
/home/root/git/qemu2.git/hw/i386/pc.c:1101
#10 0x00005555557fa33e in pc_cpus_init (address@hidden)
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=<optimized out>, argv=<optimized out>,
envp=<optimized out>) at vl.c:4562
Signed-off-by: Anthony Xu <address@hidden>
Message-id: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
qom/cpu.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/qom/cpu.c b/qom/cpu.c
index f02e9c0..f9111a0 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);
}
--
2.9.3