[PATCH] do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY

Fix a bug in mm/mlock.c on 32-bit architectures that prevents a user from
locking more than 4GB of shared memory, or allocating more than 4GB of
shared memory in hugepages, when rlim[RLIMIT_MEMLOCK] is set to
RLIM_INFINITY.

Signed-off-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/mm/mlock.c b/mm/mlock.c
index 3446b7ef731e6c419cc0cf2656829eeca6fea5a7..ef8fc94b061731d3937b36c52793b7f8b23f23f4 100644 (file)
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -233,9 +233,12 @@ int user_shm_lock(size_t size, struct user_struct *user)
 
        locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
        lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+       if (lock_limit == RLIM_INFINITY)
+               allowed = 1;
        lock_limit >>= PAGE_SHIFT;
        spin_lock(&shmlock_user_lock);
-       if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
+       if (!allowed &&
+           locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
                goto out;
        get_uid(user);
        user->locked_shm += locked;