When a normal user is trying to allocate huge pages using shmget(), the
user is not able to get the memory even if the gid is present in
/proc/sys/vm/hugetlb_shm_group. The function user_shm_lock() is not
successful. The user does not have the capability to perform a
CAP_IPC_LOCK. A check is added here to see whether the gid is present in
hugetlb_shm_group. Please review the patch.
Signed-off-by: Ciju Rajan (ciju@linux.vnet.ibm.com)
---
--- linux-2.6.23/mm/mlock.c.orig 2007-11-14 17:35:02.000000000 +0530
+++ linux-2.6.23/mm/mlock.c 2007-11-14 17:50:31.000000000 +0530
@@ -8,6 +8,7 @@
#include <linux/capability.h>
#include <linux/mman.h>
#include <linux/mm.h>
+#include <linux/hugetlb.h>
#include <linux/mempolicy.h>
#include <linux/syscalls.h>
#include <linux/sched.h>
@@ -248,8 +249,14 @@ int user_shm_lock(size_t size, struct us
allowed = 1;
lock_limit >>= PAGE_SHIFT;
spin_lock(&shmlock_user_lock);
+#ifdef CONFIG_HUGETLB_PAGE
+ if (!allowed &&
+ locked + user->locked_shm > lock_limit &&
+ (!(capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group))))
+#else
if (!allowed &&
locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
+#endif
goto out;
get_uid(user);
user->locked_shm += locked;
-
