From 5a6af9724369b321f0ae4459403ef76e4a7bd507 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 27 Oct 2014 14:05:10 +0000 Subject: [PATCH] Make qemu_shutdown_requested signal-safe qemu_shutdown_requested may be interrupted by qemu_system_killed. If the latter sets shutdown_requested after qemu_shutdown_requested has read it but before it was cleared, the shutdown event is lost. Fix this by using atomic_xchg. This provides a different fix for the problem which commit 15124e142 attempts to deal with. That commit breaks use of ^C to drop into gdb, and so this approach is better (and 15124e142 can be reverted). Signed-off-by: Jan Kiszka Reviewed-by: Gonglei Reviewed-by: Paolo Bonzini [PMM: commit message tweak] Signed-off-by: Peter Maydell (cherry picked from commit 817ef04db2cfa2df04daffd6917f4ea7605f6403) Signed-off-by: Michael Roth --- vl.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/vl.c b/vl.c index 7f8bd39c7069..3650f4fb74e4 100644 --- a/vl.c +++ b/vl.c @@ -1745,9 +1745,7 @@ int qemu_reset_requested_get(void) static int qemu_shutdown_requested(void) { - int r = shutdown_requested; - shutdown_requested = 0; - return r; + return atomic_xchg(&shutdown_requested, 0); } static void qemu_kill_report(void)