linux-kernel - [PATCH] do not limit locked memory when RLIMIT_MEMLOCK is RLIM

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Date:	Mon, 09 Jul 2007 17:59:12 -0700
From:	Herbert van den Bergh <Herbert.van.den.Bergh@...cle.com>
To:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
CC:	akpm@...ux-foundation.org,
	Dave McCracken <dave.mccracken@...cle.com>,
	Chris Mason <chris.mason@...cle.com>
Subject: [PATCH] do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY


[resending, since my previous message had tabs converted to spaces]

This patch fixes 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@...cle.com>
Acked-by: Chris Mason <chris.mason@...cle.com>

--- linux-2.6.22/mm/mlock.c.orig	2007-07-09 10:19:31.000000000 -0700
+++ linux-2.6.22/mm/mlock.c	2007-07-09 10:19:19.000000000 -0700
@@ -244,9 +244,12 @@ int user_shm_lock(size_t size, struct us
 
 	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;
-
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