RE: which signal is sent to freeze process?

From: Agarwal, Lomesh
Date: Mon Jul 23 2007 - 16:57:48 EST


Why do you need try_to_freeze in below patch? Shouldn't
!freezing(current) checking is enough?

-----Original Message-----
From: Rafael J. Wysocki [mailto:rjw@xxxxxxx]
Sent: Friday, July 20, 2007 3:10 PM
To: Agarwal, Lomesh
Cc: nigel@xxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: which signal is sent to freeze process?

On Friday, 20 July 2007 20:07, Agarwal, Lomesh wrote:
> Can you suggest a way I can debug the issue why I am getting EINTR
error
> for system calls in resuming? What else can cause the system call
> failure with EINTR?

Well, I think I know what the problem is. do_poll checks
signal_pending(current) and breaks when it's set, but that may be caused
by the freezer.

You may try the patch below (untested) and see if that helps.

Greetings,
Rafael


---
fs/select.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

Index: linux-2.6.22-rc6-mm1/fs/select.c
===================================================================
--- linux-2.6.22-rc6-mm1.orig/fs/select.c
+++ linux-2.6.22-rc6-mm1/fs/select.c
@@ -23,6 +23,7 @@
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/rcupdate.h>
+#include <linux/freezer.h>

#include <asm/uaccess.h>

@@ -593,6 +594,8 @@ static int do_poll(unsigned int nfds, s
struct poll_list *walk;
long __timeout;

+ try_to_freeze();
+
set_current_state(TASK_INTERRUPTIBLE);
for (walk = list; walk != NULL; walk = walk->next) {
struct pollfd * pfd, * pfd_end;
@@ -618,7 +621,8 @@ static int do_poll(unsigned int nfds, s
* a poll_table to them on the next loop iteration.
*/
pt = NULL;
- if (count || !*timeout || signal_pending(current))
+ if (count || !*timeout ||
+ (signal_pending(current) && !freezing(current)))
break;
count = wait->error;
if (count)
-
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