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do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY

PATCH In review Herbert van den Bergh 3 participants 3 messages Jul 10, 2007

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Herbert van den Bergh

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#0 lore raw

PATCH 1/1 do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY

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 <[email protected]>
Acked-by Chris Mason <[email protected]>
mm/mlock.c 2007-07-09 10:19:19.000000000 -0700 renamed from mm/mlock.c.orig 2007-07-09 10:19:31.000000000 -0700 +4 -1
@@ -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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#1 lore raw
Quoted 6 lines · On Mon, 09 Jul 2007 17:26:24 -0700 Herbert van den Bergh…

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.

just curious...why a resouce which can be used longer than a process's lifetime is limited by RLIMIT ?

Thanks,
-Kame

Quoted 26 lines
Signed-off-by Herbert van den Bergh <[email protected]>
Acked-by Chris Mason <[email protected]>
mm/mlock.c 2007-07-09 10:19:19.000000000 -0700 renamed from mm/mlock.c.orig 2007-07-09 10:19:31.000000000 -0700 +4 -2
@@ -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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#2 lore raw
In reply to Herbert van den Bergh
Quoted 5 lines · On Mon, 09 Jul 2007 17:26:24 -0700 Herbert van den Bergh wrote:

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.

Something has converted tabs to spaces in your patch. Ah, thunderbird. Did you use an external editor plugin?

If not, did you use preformat and other instructions from
http://mbligh.org/linuxdocs/Email/Clients/Thunderbird ?

Please send a patch to yourself and make sure that you can apply the received patch cleanly.

Quoted 9 lines
Signed-off-by Herbert van den Bergh <[email protected]>
Acked-by Chris Mason <[email protected]>
mm/mlock.c 2007-07-09 10:19:19.000000000 -0700 renamed from mm/mlock.c.orig 2007-07-09 10:19:31.000000000 -0700 +0 -0
@@ -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;

mm/mlock.c 2007-07-09 10:19:19.000000000 -0700 int user_shm_lock(size_t size, struct us · line 255

Quoted 10 lines
mm/mlock.c 2007-07-09 10:19:19.000000000 -0700 renamed from mm/mlock.c.orig 2007-07-09 10:19:31.000000000 -0700 +4 -1
+    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;

---
~Randy
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