Subject: + ipcshm-shorten-critical-region-for-shmat.patch added to -mm tree
To: davidlohr.bueso@xxxxxx,manfred@xxxxxxxxxxxxxxxx,riel@xxxxxxxxxx,sedat.dilek@xxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 16 Jul 2013 15:51:51 -0700
The patch titled
Subject: ipc,shm: shorten critical region for shmat
has been added to the -mm tree. Its filename is
ipcshm-shorten-critical-region-for-shmat.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ipcshm-shorten-critical-region-for-shmat.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ipcshm-shorten-critical-region-for-shmat.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Davidlohr Bueso <davidlohr.bueso@xxxxxx>
Subject: ipc,shm: shorten critical region for shmat
Similar to other system calls, acquire the kern_ipc_perm lock after doing
the initial permission and security checks.
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 | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff -puN ipc/shm.c~ipcshm-shorten-critical-region-for-shmat ipc/shm.c
--- a/ipc/shm.c~ipcshm-shorten-critical-region-for-shmat
+++ a/ipc/shm.c
@@ -19,6 +19,9 @@
* namespaces support
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <xemul@xxxxxxxxxx>
+ *
+ * Better ipc lock (kern_ipc_perm.lock) handling
+ * Davidlohr Bueso <davidlohr.bueso@xxxxxx>, June 2013.
*/
#include <linux/slab.h>
@@ -1086,7 +1089,8 @@ long do_shmat(int shmid, char __user *sh
* additional creator id...
*/
ns = current->nsproxy->ipc_ns;
- 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;
@@ -1100,11 +1104,13 @@ long do_shmat(int shmid, char __user *sh
if (err)
goto out_unlock;
+ ipc_lock_object(&shp->shm_perm);
path = shp->shm_file->f_path;
path_get(&path);
shp->shm_nattch++;
size = i_size_read(path.dentry->d_inode);
- shm_unlock(shp);
+ ipc_unlock_object(&shp->shm_perm);
+ rcu_read_unlock();
err = -ENOMEM;
sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
@@ -1175,7 +1181,7 @@ out_nattch:
return err;
out_unlock:
- shm_unlock(shp);
+ rcu_read_unlock();
out:
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
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
