diff options
authorPaolo Bonzini <>2012-09-03 17:34:32 +0200
committerMichael Roth <>2012-09-05 10:38:39 -0500
commitf965d237b567389661bccb1701a6c94e964d7818 (patch)
parenttarget-xtensa: return ENOSYS for unimplemented simcalls (diff)
qemu-timer: properly arm alarm timer for timers set by device initialization
QEMU will hang when fed the following command-line qemu-system-mips -kernel vmlinux-2.6.32-5-4kc-malta -append "console=ttyS0" -nographic -net none The -net none is important otherwise it seems some events are generated causing the things to work. When it doesn't work, the guest hangs when measuring the CPU frequency, after the following line: [ 0.000000] NR_IRQS:256 Pressing a key on the serial port unblocks it, hinting that the problem is due to the recent elimination of the 1 second timeout in the main loop. The problem is that because init_timer_alarm sets the timer's pending flag to true, the alarm timer is never armed until after the first time through the main loop. Thus the bug started when QEMU started testing the pending flag in qemu_mod_timer (commit 1828be3, more alarm timer cleanup, 2010-03-10). But actually, it isn't true at all that a timer is pending when the alarm timer is created, and the real bug has been latent forever: the fix is to remove the bogus setting of pending flag. Reported-by: Aurelien Jarno <> Signed-off-by: Paolo Bonzini <> Reviewed-by: Jan Kiszka <> Tested-by: Aurelien Jarno <> Tested-by: Michael Tokarev <> Signed-off-by: Aurelien Jarno <> (cherry picked from commit de188751da8db3c77a681bf903035a0e5218c463) Signed-off-by: Michael Roth <>
1 files changed, 0 insertions, 3 deletions
diff --git a/qemu-timer.c b/qemu-timer.c
index d37a97839..91e4c1455 100644
--- a/qemu-timer.c
+++ b/qemu-timer.c
@@ -759,11 +759,8 @@ int init_timer_alarm(void)
goto fail;
- /* first event is at time 0 */
- t->pending = true;
alarm_timer = t;
return 0;