[PATCH] lguest: move process freezing before pending signals check

From: Michal Hocko
Date: Tue Sep 27 2011 - 02:56:03 EST


run_guest tries to freeze the current process after it has handled
pending interrupts and before it calls lguest_arch_run_guest.
This doesn't work nicely if the task has been killed while being frozen
and when we want to handle that signal as soon as possible.
Let's move try_to_freeze before we check for pending signal so that we
can get out of the loop as soon as possible.

Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
---
drivers/lguest/core.c | 14 +++++++-------
1 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index 2535933..e7dda91 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -232,6 +232,13 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
}
}

+ /*
+ * All long-lived kernel loops need to check with this horrible
+ * thing called the freezer. If the Host is trying to suspend,
+ * it stops us.
+ */
+ try_to_freeze();
+
/* Check for signals */
if (signal_pending(current))
return -ERESTARTSYS;
@@ -246,13 +253,6 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
try_deliver_interrupt(cpu, irq, more);

/*
- * All long-lived kernel loops need to check with this horrible
- * thing called the freezer. If the Host is trying to suspend,
- * it stops us.
- */
- try_to_freeze();
-
- /*
* Just make absolutely sure the Guest is still alive. One of
* those hypercalls could have been fatal, for example.
*/
--
1.7.5.4

--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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