Re: [Qemu-devel] [PATCH] cpus: fix TCG timer leak

[Marc-André Lureau]

Hi

On Thu, Sep 27, 2018 at 5:57 PM Alex Bennée <address@hidden> wrote:
>
>
> Marc-André Lureau <address@hidden> writes:
>
> > Spotted by ASAN:
> >
> > QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 tests/bios-tables-test  
> > -p /x86_64/acpi/piix4/cpuhp
> > /x86_64/acpi/piix4/cpuhp: Could not access KVM kernel module: No such file 
> > or directory
> > qemu-system-x86_64: failed to initialize KVM: No such file or directory
> > qemu-system-x86_64: Back to tcg accelerator
> > ==21216==WARNING: ASan doesn't fully support makecontext/swapcontext 
> > functions and may produce false positives in some cases!
> >
> > =================================================================
> > ==21216==ERROR: LeakSanitizer: detected memory leaks
> >
> > Direct leak of 48 byte(s) in 1 object(s) allocated from:
> >     #0 0x7f77c0668e50 in calloc (/lib64/libasan.so.5+0xeee50)
> >     #1 0x7f77beb7b41d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5241d)
> >     #2 0x557f756df5bd in timer_new 
> > /home/elmarco/src/qemu/include/qemu/timer.h:561
> >     #3 0x557f756df5ee in timer_new_ns 
> > /home/elmarco/src/qemu/include/qemu/timer.h:584
> >     #4 0x557f756e4690 in start_tcg_kick_timer 
> > /home/elmarco/src/qemu/cpus.c:965
> >     #5 0x557f756e64d7 in qemu_tcg_rr_wait_io_event 
> > /home/elmarco/src/qemu/cpus.c:1210
> >     #6 0x557f756e90ad in qemu_tcg_rr_cpu_thread_fn 
> > /home/elmarco/src/qemu/cpus.c:1536
> >     #7 0x557f76e9f233 in qemu_thread_start 
> > /home/elmarco/src/qemu/util/qemu-thread-posix.c:504
> >     #8 0x7f77b4a11593 in start_thread (/lib64/libpthread.so.0+0x7593)
>
> I'm trying to reproduce to try the alternate approach but I can't get
> the full object backtraces:
>
> 14:56:08 address@hidden:~/l/q/qemu.git] misc/tcg-timer-fix(1) 2 + env 
> QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 tests/bios-tables-test  
> -p /x86_64/acpi/piix4/cpuhp
> /x86_64/acpi/piix4/cpuhp: ==30510==WARNING: ASan doesn't fully support 
> makecontext/swapcontext functions and may produce false positives in some 
> cases!
> /home/alex/lsrc/qemu/qemu.git/include/qemu/rcu.h:78:21: runtime error: member 
> access within null pointer of type 'struct rcu_reader_data'
> /home/alex/lsrc/qemu/qemu.git/include/qemu/rcu.h:93:5: runtime error: member 
> access within null pointer of type 'struct rcu_reader_data'
> /home/alex/lsrc/qemu/qemu.git/include/qemu/rcu.h:94:8: runtime error: member 
> access within null pointer of type 'struct rcu_reader_data'
> /home/alex/lsrc/qemu/qemu.git/include/qemu/rcu.h:93:5: runtime error: member 
> access within null pointer of type 'struct rcu_reader_data'
> OK
>
> What is your configure setup?

It's run in the docker build, where /dev/kvm isn't available (not sure why btw)

"/x86_64/acpi/piix4/cpuhp: Could not access KVM kernel module: No such
file or directory"

>
> --
> Alex Bennée