linux/ipc, branch v2.6.30.6

mm: fix hugetlb bug due to user_shm_unlock call

2009-09-09T03:33:20Z

commit 353d5c30c666580347515da609dd74a2b8e9b828 upstream. 2.6.30's commit 8a0bdec194c21c8fdef840989d0d7b742bb5d4bc removed user_shm_lock() calls in hugetlb_file_setup() but left the user_shm_unlock call in shm_destroy(). In detail: Assume that can_do_hugetlb_shm() returns true and hence user_shm_lock() is not called in hugetlb_file_setup(). However, user_shm_unlock() is called in any case in shm_destroy() and in the following atomic_dec_and_lock(&up->__count) in free_uid() is executed and if up->__count gets zero, also cleanup_user_struct() is scheduled. Note that sched_destroy_user() is empty if CONFIG_USER_SCHED is not set. However, the ref counter up->__count gets unexpectedly non-positive and the corresponding structs are freed even though there are live references to them, resulting in a kernel oops after a lots of shmget(SHM_HUGETLB)/shmctl(IPC_RMID) cycles and CONFIG_USER_SCHED set. Hugh changed Stefan's suggested patch: can_do_hugetlb_shm() at the time of shm_destroy() may give a different answer from at the time of hugetlb_file_setup(). And fixed newseg()'s no_id error path, which has missed user_shm_unlock() ever since it came in 2.6.9. Reported-by: Stefan Huber Signed-off-by: Hugh Dickins Tested-by: Stefan Huber Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

shm: fix unused warnings on nommu

2009-06-09T23:59:03Z

The massive nommu update (8feae131) resulted in these warnings: ipc/shm.c: In function `sys_shmdt': ipc/shm.c:974: warning: unused variable `size' ipc/shm.c:972: warning: unused variable `next' Signed-off-by: Mike Frysinger Cc: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

namespaces: move get_mq() inside #ifdef CONFIG_SYSCTL

2009-04-13T22:04:29Z

| ipc/mq_sysctl.c:26: warning: 'get_mq' defined but not used Signed-off-by: Geert Uytterhoeven Acked-by: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

namespaces: mqueue namespace: adapt sysctl

2009-04-07T15:31:09Z

Largely inspired from ipc/ipc_sysctl.c. This patch isolates the mqueue sysctl stuff in its own file. [akpm@linux-foundation.org: build fix] Signed-off-by: Cedric Le Goater Signed-off-by: Nadia Derbey Signed-off-by: Serge E. Hallyn Cc: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

namespaces: ipc namespaces: implement support for posix msqueues

2009-04-07T15:31:09Z

Implement multiple mounts of the mqueue file system, and link it to usage of CLONE_NEWIPC. Each ipc ns has a corresponding mqueuefs superblock. When a user does clone(CLONE_NEWIPC) or unshare(CLONE_NEWIPC), the unshare will cause an internal mount of a new mqueuefs sb linked to the new ipc ns. When a user does 'mount -t mqueue mqueue /dev/mqueue', he mounts the mqueuefs superblock. Posix message queues can be worked with both through the mq_* system calls (see mq_overview(7)), and through the VFS through the mqueue mount. Any usage of mq_open() and friends will work with the acting task's ipc namespace. Any actions through the VFS will work with the mqueuefs in which the file was created. So if a user doesn't remount mqueuefs after unshare(CLONE_NEWIPC), mq_open("/ab") will not be reflected in "ls /dev/mqueue". If task a mounts mqueue for ipc_ns:1, then clones task b with a new ipcns, ipcns:2, and then task a is the last task in ipc_ns:1 to exit, then (1) ipc_ns:1 will be freed, (2) it's superblock will live on until task b umounts the corresponding mqueuefs, and vfs actions will continue to succeed, but (3) sb->s_fs_info will be NULL for the sb corresponding to the deceased ipc_ns:1. To make this happen, we must protect the ipc reference count when a) a task exits and drops its ipcns->count, since it might be dropping it to 0 and freeing the ipcns b) a task accesses the ipcns through its mqueuefs interface, since it bumps the ipcns refcount and might race with the last task in the ipcns exiting. So the kref is changed to an atomic_t so we can use atomic_dec_and_lock(&ns->count,mq_lock), and every access to the ipcns through ns = mqueuefs_sb->s_fs_info is protected by the same lock. Signed-off-by: Cedric Le Goater Signed-off-by: Serge E. Hallyn Cc: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

namespaces: mqueue ns: move mqueue_mnt into struct ipc_namespace

2009-04-07T15:31:09Z

Move mqueue vfsmount plus a few tunables into the ipc_namespace struct. The CONFIG_IPC_NS boolean and the ipc_namespace struct will serve both the posix message queue namespaces and the SYSV ipc namespaces. The sysctl code will be fixed separately in patch 3. After just this patch, making a change to posix mqueue tunables always changes the values in the initial ipc namespace. Signed-off-by: Cedric Le Goater Signed-off-by: Serge E. Hallyn Cc: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

2009-04-03T04:09:10Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: Remove two unneeded exports and make two symbols static in fs/mpage.c Cleanup after commit 585d3bc06f4ca57f975a5a1f698f65a45ea66225 Trim includes of fdtable.h Don't crap into descriptor table in binfmt_som Trim includes in binfmt_elf Don't mess with descriptor table in load_elf_binary() Get rid of indirect include of fs_struct.h New helper - current_umask() check_unsafe_exec() doesn't care about signal handlers sharing New locking/refcounting for fs_struct Take fs_struct handling to new file (fs/fs_struct.c) Get rid of bumping fs_struct refcount in pivot_root(2) Kill unsharing fs_struct in __set_personality()

proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers

2009-04-03T02:05:01Z

As pointed out by Cedric Le Goater (in response to Alexey's original comment wrt mqns), ipc_sysctl.c and utsname_sysctl.c are using CONFIG_PROC_FS, not CONFIG_PROC_SYSCTL, to determine whether to define the proc_handlers. Change that. Signed-off-by: Serge E. Hallyn Cc: Cedric Le Goater Acked-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: make shm_get_stat() more robust

2009-04-03T02:05:01Z

shm_get_stat() assumes idr_find(&shm_ids(ns).ipcs_idr) returns "struct shmid_kernel *"; all other callers assume that it returns "struct kern_ipc_perm *". This works because "struct kern_ipc_perm" is currently the first member of "struct shmid_kernel", but it would be better to use container_of() to prevent future breakage. Signed-off-by: Tony Battersby Cc: Jiri Olsa Cc: Jiri Kosina Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

New helper - current_umask()

2009-04-01T03:00:26Z

current->fs->umask is what most of fs_struct users are doing. Put that into a helper function. Signed-off-by: Al Viro