projects/linux·commit d69f3bad

ipc: sysv shared memory limited to 8TiB

d69f3bad · Robin Holt <[email protected]> · 2013-04-30 19:15:54 -07:00

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;

[[email protected]: make ipc/shm.c:newseg()'s numpages size_t, not int]
Signed-off-by: Robin Holt <[email protected]>
Reported-by: Alex Thorlton <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Commit
d69f3bad4675ac519d41ca2b11e1c00ca115cecd
Parents
41239fe8

Changes

2 files changed · +2 −2

FileStatusAddDelContent
include/linux/ipc_namespace.hmodified+1−1View file
ipc/shm.cmodified+1−1View file

include/linux/ipc_namespace.h

View file
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index ae221a7..c4d870b 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -43,8 +43,8 @@ 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()

ipc/shm.c

View file
diff --git a/ipc/shm.c b/ipc/shm.c
index cb858df..8247c49 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;