[ 3.5.y.z extended stable ] Patch "ipc: sysv shared memory limited to 8TiB" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ipc: sysv shared memory limited to 8TiB

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 234019cbd2d49630dde5612a384aa2de3a893015 Mon Sep 17 00:00:00 2001
From: Robin Holt <holt at sgi.com>
Date: Tue, 30 Apr 2013 19:15:54 -0700
Subject: [PATCH] ipc: sysv shared memory limited to 8TiB

commit d69f3bad4675ac519d41ca2b11e1c00ca115cecd upstream.

Trying to run an application which was trying to put data into half of
memory using shmget(), we found that having a shmall value below 8EiB-8TiB
would prevent us from using anything more than 8TiB.  By setting
kernel.shmall greater than 8EiB-8TiB would make the job work.

In the newseg() function, ns->shm_tot which, at 8TiB is INT_MAX.

ipc/shm.c:
 458 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 459 {
...
 465         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
...
 474         if (ns->shm_tot + numpages > ns->shm_ctlall)
 475                 return -ENOSPC;

[akpm at linux-foundation.org: make ipc/shm.c:newseg()'s numpages size_t, not int]
Signed-off-by: Robin Holt <holt at sgi.com>
Reported-by: Alex Thorlton <athorlton at sgi.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 include/linux/ipc_namespace.h | 2 +-
 ipc/shm.c                     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 5499c92..c731973 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -42,8 +42,8 @@ struct ipc_namespace {

 	size_t		shm_ctlmax;
 	size_t		shm_ctlall;
+	unsigned long	shm_tot;
 	int		shm_ctlmni;
-	int		shm_tot;
 	/*
 	 * Defines whether IPC_RMID is forced for _all_ shm segments regardless
 	 * of shmctl()
diff --git a/ipc/shm.c b/ipc/shm.c
index 41c1285..f5ba6ac 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -462,7 +462,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 	size_t size = params->u.size;
 	int error;
 	struct shmid_kernel *shp;
-	int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
+	size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	struct file * file;
 	char name[13];
 	int id;
--
1.8.1.2