[PATCH] cpuset - fix return without releasing semaphore

[PATCH] cpuset - fix return without releasing semaphore

[bob.picco]

It seems wrong to acquire the semaphore and then return from 
cpuset_zone_allowed without releasing it.  This was only compile tested.

bob

Signed-off-by: Bob Picco <bob.picco@hp.com>

 kernel/cpuset.c |    5 +++--

 1 files changed, 3 insertions(+), 2 deletions(-)

Index: linux-2.6.14-mm1/kernel/cpuset.c
===================================================================
--- linux-2.6.14-mm1.orig/kernel/cpuset.c	2005-11-07 07:00:13.000000000 -0500
+++ linux-2.6.14-mm1/kernel/cpuset.c	2005-11-09 17:56:28.000000000 -0500
@@ -2036,11 +2036,12 @@ int cpuset_zone_allowed(struct zone *z, 
 	if (gfp_mask & __GFP_HARDWALL)	/* If hardwall request, stop here */
 		return 0;
 
+	if (current->flags & PF_EXITING) /* Let dying task have memory */
+		return 1;
+
 	/* Not hardwall and node outside mems_allowed: scan up cpusets */
 	down(&callback_sem);
 
-	if (current->flags & PF_EXITING) /* Let dying task have memory */
-		return 1;
 	task_lock(current);
 	cs = nearest_exclusive_ancestor(current->cpuset);
 	task_unlock(current);

Re: [PATCH] cpuset - fix return without releasing semaphore

[Paul Jackson]

Bob wrote:
> It seems wrong to acquire the semaphore and then return from 
> cpuset_zone_allowed without releasing it.  This was only compile tested.

Acked-by: Paul Jackson <pj@sgi.com>

Nice catch, Bob.  Thanks.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

Re: [PATCH] cpuset - fix return without releasing semaphore

[Paul Jackson]

> This was only compile tested.

I boot, function and stress tested it on an ia64 SN2 system.
As expected, works fine, just as it did before.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401