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Re: [Qemu-devel] R: qemu-nbd segmentation fault
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] R: qemu-nbd segmentation fault |
Date: |
Thu, 19 Sep 2013 12:05:58 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Sep 18, 2013 at 03:35:12PM +0200, Mario DE CHENNO wrote:
> This time crashed just issuing a mount command:
>
> Starting program: /vmstore/vmtools/qemu-nbd-from1.6.0
> /vmstore/playground/archivioweb.img
> [Thread debugging using libthread_db enabled]
> [New Thread 0x7ffff55e3700 (LWP 7626)]
> [New Thread 0x7ffff47dd700 (LWP 7645)]
> [New Thread 0x7ffff3fdc700 (LWP 7646)]
> [New Thread 0x7ffff37db700 (LWP 7647)]
>
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7ffff37db700 (LWP 7647)]
> 0x00007ffff7717249 in ?? () from /usr/lib64/libglib-2.0.so.0
> (gdb) bt
> #0 0x00007ffff7717249 in ?? () from /usr/lib64/libglib-2.0.so.0
> #1 0x00007ffff771759c in ?? () from /usr/lib64/libglib-2.0.so.0
> #2 0x00007ffff7718958 in g_slice_free1 () from /usr/lib64/libglib-2.0.so.0
> #3 0x0000555555591c2d in aio_worker (arg=0x555555c2f6c0) at
> block/raw-posix.c:776
> #4 0x00005555555da094 in worker_thread (opaque=0x555555c31a40) at
> thread-pool.c:109
> #5 0x00007ffff6c2ed6b in start_thread () from /lib64/libpthread.so.0
> #6 0x00007ffff6966abd in clone () from /lib64/libc.so.6
Please try this patch and let us know if it worked.
Older glib versions required the application to call g_thread_init().
Failure to do so results in the single-threaded code path being used.
In a multi-threaded application that means race conditions and I've seen
crashes similar to the backtrace you've posted.
diff --git a/qemu-nbd.c b/qemu-nbd.c
index c26c98e..8ae3868 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -357,6 +357,15 @@ int main(int argc, char **argv)
const char *fmt = NULL;
Error *local_err = NULL;
+ if (!g_thread_supported()) {
+#if !GLIB_CHECK_VERSION(2, 31, 0)
+ g_thread_init(NULL);
+#else
+ fprintf(stderr, "glib threading failed to initialize.\n");
+ exit(1);
+#endif
+ }
+
/* The client thread uses SIGTERM to interrupt the server. A signal
* handler ensures that "qemu-nbd -v -c" exits with a nice status code.
*/