Subject: + ipcshm-shorten-critical-region-for-shmctl.patch added to -mm tree
To: davidlohr.bueso@xxxxxx,manfred@xxxxxxxxxxxxxxxx,riel@xxxxxxxxxx,sedat.dilek@xxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 16 Jul 2013 15:51:49 -0700
The patch titled
Subject: ipc,shm: shorten critical region for shmctl
has been added to the -mm tree. Its filename is
ipcshm-shorten-critical-region-for-shmctl.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ipcshm-shorten-critical-region-for-shmctl.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ipcshm-shorten-critical-region-for-shmctl.patch
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------------------------------------------------------
From: Davidlohr Bueso <davidlohr.bueso@xxxxxx>
Subject: ipc,shm: shorten critical region for shmctl
With the *_INFO, *_STAT, IPC_RMID and IPC_SET commands already optimized,
deal with the remaining SHM_LOCK and SHM_UNLOCK commands. Take the
shm_perm lock after doing the initial auditing and security checks. The
rest of the logic remains unchanged.
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@xxxxxx>
Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/shm.c | 49 +++++++++++++++++++++++++------------------------
1 file changed, 25 insertions(+), 24 deletions(-)
diff -puN ipc/shm.c~ipcshm-shorten-critical-region-for-shmctl ipc/shm.c
--- a/ipc/shm.c~ipcshm-shorten-critical-region-for-shmctl
+++ a/ipc/shm.c
@@ -940,10 +940,8 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int,
int err, version;
struct ipc_namespace *ns;
- if (cmd < 0 || shmid < 0) {
- err = -EINVAL;
- goto out;
- }
+ if (cmd < 0 || shmid < 0)
+ return -EINVAL;
version = ipc_parse_version(&cmd);
ns = current->nsproxy->ipc_ns;
@@ -954,36 +952,40 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int,
case SHM_STAT:
case IPC_STAT:
return shmctl_nolock(ns, shmid, cmd, version, buf);
+ case IPC_RMID:
+ case IPC_SET:
+ return shmctl_down(ns, shmid, cmd, buf, version);
case SHM_LOCK:
case SHM_UNLOCK:
{
struct file *shm_file;
- shp = shm_lock_check(ns, shmid);
+ rcu_read_lock();
+ shp = shm_obtain_object_check(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
- goto out;
+ goto out_unlock1;
}
audit_ipc_obj(&(shp->shm_perm));
+ err = security_shm_shmctl(shp, cmd);
+ if (err)
+ goto out_unlock1;
+ ipc_lock_object(&shp->shm_perm);
if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
kuid_t euid = current_euid();
err = -EPERM;
if (!uid_eq(euid, shp->shm_perm.uid) &&
!uid_eq(euid, shp->shm_perm.cuid))
- goto out_unlock;
+ goto out_unlock0;
if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
- goto out_unlock;
+ goto out_unlock0;
}
- err = security_shm_shmctl(shp, cmd);
- if (err)
- goto out_unlock;
-
shm_file = shp->shm_file;
if (is_file_hugepages(shm_file))
- goto out_unlock;
+ goto out_unlock0;
if (cmd == SHM_LOCK) {
struct user_struct *user = current_user();
@@ -992,32 +994,31 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int,
shp->shm_perm.mode |= SHM_LOCKED;
shp->mlock_user = user;
}
- goto out_unlock;
+ goto out_unlock0;
}
/* SHM_UNLOCK */
if (!(shp->shm_perm.mode & SHM_LOCKED))
- goto out_unlock;
+ goto out_unlock0;
shmem_lock(shm_file, 0, shp->mlock_user);
shp->shm_perm.mode &= ~SHM_LOCKED;
shp->mlock_user = NULL;
get_file(shm_file);
- shm_unlock(shp);
+ ipc_unlock_object(&shp->shm_perm);
+ rcu_read_unlock();
shmem_unlock_mapping(shm_file->f_mapping);
+
fput(shm_file);
- goto out;
- }
- case IPC_RMID:
- case IPC_SET:
- err = shmctl_down(ns, shmid, cmd, buf, version);
return err;
+ }
default:
return -EINVAL;
}
-out_unlock:
- shm_unlock(shp);
-out:
+out_unlock0:
+ ipc_unlock_object(&shp->shm_perm);
+out_unlock1:
+ rcu_read_unlock();
return err;
}
_
Patches currently in -mm which might be from davidlohr.bueso@xxxxxx are
linux-next.patch
ipcshm-introduce-lockless-functions-to-obtain-the-ipc-object.patch
ipcshm-shorten-critical-region-in-shmctl_down.patch
ipc-drop-ipcctl_pre_down.patch
ipc-drop-ipcctl_pre_down-fix.patch
ipcshm-introduce-shmctl_nolock.patch
ipcshm-make-shmctl_nolock-lockless.patch
ipcshm-shorten-critical-region-for-shmctl.patch
ipcshm-cleanup-do_shmat-pasta.patch
ipcshm-shorten-critical-region-for-shmat.patch
ipc-rename-ids-rw_mutex.patch
ipcmsg-drop-msg_unlock.patch
ipc-document-general-ipc-locking-scheme.patch
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