[2.6.20.17 review 40/58] do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY

[Willy Tarreau]

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@xxxxxxxxxx>
Acked-by: Chris Mason <chris.mason@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
 mm/mlock.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 3446b7e..ef8fc94 100644
--- 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;
-- 
1.5.2.5

-- 
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