[Qemu-devel] [PATCH] initialize struct sigevent before timer_create

[Qemu-devel] [PATCH] initialize struct sigevent before timer_create

[Jean-Christophe Dubois]

When qemu is run under valgrind, valgrind shows the following output
on exit:

==3648== 1 errors in context 2 of 2:                                                                        
==3648== Syscall param timer_create(evp) points to uninitialised byte(s)                                    
==3648==    at 0x54E936A: timer_create (in /lib/librt-2.9.so)                                               
==3648==    by 0x405DCF: dynticks_start_timer (vl.c:1549)                                                   
==3648==    by 0x40A966: main (vl.c:1726)                                                                   
==3648==  Address 0x7fefffb34 is on thread 1's stack                                                        
==3648==  Uninitialised value was created by a stack allocation                                             
==3648==    at 0x405D60: dynticks_start_timer (vl.c:1534)

This patch is a simple fix to remove this potential problem.

Signed-off-by: Jean-Christophe DUBOIS <jcd@tribudubois.net>

--- qemu.org/vl.c	2009-05-16 17:57:27.000000000 +0200
+++ qemu/vl.c	2009-05-16 23:06:52.000000000 +0200
@@ -1542,6 +1542,11 @@
 
     sigaction(SIGALRM, &act, NULL);
 
+    /* 
+     * Initialize ev struct to 0 to avoid valgrind complaining
+     * about uninitialized data in timer_create call
+     */
+    memset(&ev, 0, sizeof(ev));
     ev.sigev_value.sival_int = 0;
     ev.sigev_notify = SIGEV_SIGNAL;
     ev.sigev_signo = SIGALRM;

Re: [Qemu-devel] [PATCH] initialize struct sigevent before timer_create

[Marcelo Tosatti]

Looks good.

On Sun, May 17, 2009 at 06:41:16PM +0200, Jean-Christophe Dubois wrote:
> When qemu is run under valgrind, valgrind shows the following output
> on exit:
> 
> ==3648== 1 errors in context 2 of 2:                                                                        
> ==3648== Syscall param timer_create(evp) points to uninitialised byte(s)                                    
> ==3648==    at 0x54E936A: timer_create (in /lib/librt-2.9.so)                                               
> ==3648==    by 0x405DCF: dynticks_start_timer (vl.c:1549)                                                   
> ==3648==    by 0x40A966: main (vl.c:1726)                                                                   
> ==3648==  Address 0x7fefffb34 is on thread 1's stack                                                        
> ==3648==  Uninitialised value was created by a stack allocation                                             
> ==3648==    at 0x405D60: dynticks_start_timer (vl.c:1534)
> 
> This patch is a simple fix to remove this potential problem.
> 
> Signed-off-by: Jean-Christophe DUBOIS <jcd@tribudubois.net>
> 
> --- qemu.org/vl.c	2009-05-16 17:57:27.000000000 +0200
> +++ qemu/vl.c	2009-05-16 23:06:52.000000000 +0200
> @@ -1542,6 +1542,11 @@
>  
>      sigaction(SIGALRM, &act, NULL);
>  
> +    /* 
> +     * Initialize ev struct to 0 to avoid valgrind complaining
> +     * about uninitialized data in timer_create call
> +     */
> +    memset(&ev, 0, sizeof(ev));
>      ev.sigev_value.sival_int = 0;
>      ev.sigev_notify = SIGEV_SIGNAL;
>      ev.sigev_signo = SIGALRM;
>