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* ipc: get rid of ipc_lock_down()Nadia Derbey2008-07-251-18/+3
| | | | | | | | | | | | | | | Remove the ipc_lock_down() routines: they used to call idr_find() locklessly (given that the ipc ids lock was already held), so they are not needed anymore. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Jim Houston <jim.houston@comcast.net> Cc: Pierre Peiffer <peifferp@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: modular state for hugetlb page sizeAndi Kleen2008-07-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | The goal of this patchset is to support multiple hugetlb page sizes. This is achieved by introducing a new struct hstate structure, which encapsulates the important hugetlb state and constants (eg. huge page size, number of huge pages currently allocated, etc). The hstate structure is then passed around the code which requires these fields, they will do the right thing regardless of the exact hstate they are operating on. This patch adds the hstate structure, with a single global instance of it (default_hstate), and does the basic work of converting hugetlb to use the hstate. Future patches will add more hstate structures to allow for different hugetlbfs mounts to have different page sizes. [akpm@linux-foundation.org: coding-style fixes] Acked-by: Adam Litke <agl@us.ibm.com> Acked-by: Nishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* /proc/sysvipc/shm: fix 32-bit truncation of segment sizesPaul Menage2008-06-121-8/+8
| | | | | | | | | | | | | | | | | | | | | sysvipc_shm_proc_show() picks between format strings (based on the expected maximum length of a SHM segment) in a way that prevents gcc from performing format checks on the seq_printf() parameters. This hid two format errors - shp->shm_segsz and shp->shm_nattach are both unsigned long, but were being printed as unsigned int and signed int respectively. This leads to 32-bit truncation of SHM segment sizes reported in /proc/sysvipc/shm. (And for nattach, but that's less of a problem for most users). This patch makes the format string directly visible to gcc's format specifier checker, and fixes the two broken format specifiers. Signed-off-by: Paul Menage <menage@google.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Pierre Peiffer <peifferp@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* shm: Remove silly double assignmentNeil Horman2008-06-101-2/+0
| | | | | | | | Found a silly double assignment of err is do_shmat. Silly, but good to clean up the useless code. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: consolidate all xxxctl_down() functionsPierre Peiffer2008-04-291-38/+4
| | | | | | | | | | | | | | | | | | | semctl_down(), msgctl_down() and shmctl_down() are used to handle the same set of commands for each kind of IPC. They all start to do the same job (they retrieve the ipc and do some permission checks) before handling the commands on their own. This patch proposes to consolidate this by moving these same pieces of code into one common function called ipcctl_pre_down(). It simplifies a little these xxxctl_down() functions and increases a little the maintainability. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: introduce ipc_update_perm()Pierre Peiffer2008-04-291-4/+1
| | | | | | | | | | | | The IPC_SET command performs the same permission setting for all IPCs. This patch introduces a common ipc_update_perm() function to update these permissions and makes use of it for all IPCs. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: get rid of the use *_setbuf structure.Pierre Peiffer2008-04-291-27/+14
| | | | | | | | | | | | | | | | | | All IPCs make use of an intermetiate *_setbuf structure to handle the IPC_SET command. This is not really needed and, moreover, it complicates a little bit the code. This patch gets rid of the use of it and uses directly the semid64_ds/ msgid64_ds/shmid64_ds structure. In addition of removing one struture declaration, it also simplifies and improves a little bit the common 64-bits path. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC/shared memory: introduce shmctl_downPierre Peiffer2008-04-291-88/+72
| | | | | | | | | | | | | | | | | | Currently, the way the different commands are handled in sys_shmctl introduces some duplicated code. This patch introduces the shmctl_down function to handle all the commands requiring the rwmutex to be taken in write mode (ie IPC_SET and IPC_RMID for now). It is the equivalent function of semctl_down for shared memory. This removes some duplicated code for handling these both commands and harmonizes the way they are handled among all IPCs. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: use ipc_buildid() directly from ipc_addid()Pierre Peiffer2008-04-291-9/+1
| | | | | | | | | | | | | | | By continuing to consolidate a little the IPC code, each id can be built directly in ipc_addid() instead of having it built from each callers of ipc_addid() And I also remove shm_addid() in order to have, as much as possible, the same code for shm/sem/msg. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mempolicy: rework mempolicy Reference Counting [yet again]Lee Schermerhorn2008-04-281-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After further discussion with Christoph Lameter, it has become clear that my earlier attempts to clean up the mempolicy reference counting were a bit of overkill in some areas, resulting in superflous ref/unref in what are usually fast paths. In other areas, further inspection reveals that I botched the unref for interleave policies. A separate patch, suitable for upstream/stable trees, fixes up the known errors in the previous attempt to fix reference counting. This patch reworks the memory policy referencing counting and, one hopes, simplifies the code. Maybe I'll get it right this time. See the update to the numa_memory_policy.txt document for a discussion of memory policy reference counting that motivates this patch. Summary: Lookup of mempolicy, based on (vma, address) need only add a reference for shared policy, and we need only unref the policy when finished for shared policies. So, this patch backs out all of the unneeded extra reference counting added by my previous attempt. It then unrefs only shared policies when we're finished with them, using the mpol_cond_put() [conditional put] helper function introduced by this patch. Note that shmem_swapin() calls read_swap_cache_async() with a dummy vma containing just the policy. read_swap_cache_async() can call alloc_page_vma() multiple times, so we can't let alloc_page_vma() unref the shared policy in this case. To avoid this, we make a copy of any non-null shared policy and remove the MPOL_F_SHARED flag from the copy. This copy occurs before reading a page [or multiple pages] from swap, so the overhead should not be an issue here. I introduced a new static inline function "mpol_cond_copy()" to copy the shared policy to an on-stack policy and remove the flags that would require a conditional free. The current implementation of mpol_cond_copy() assumes that the struct mempolicy contains no pointers to dynamically allocated structures that must be duplicated or reference counted during copy. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mempolicy: fixup Fallback for Default Shmem PolicyLee Schermerhorn2008-04-281-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | get_vma_policy() is not handling fallback to task policy correctly when the get_policy() vm_op returns NULL. The NULL overwrites the 'pol' variable that was holding the fallback task mempolicy. So, it was falling back directly to system default policy. Fix get_vma_policy() to use only non-NULL policy returned from the vma get_policy op. shm_get_policy() was falling back to current task's mempolicy if the "backing file system" [tmpfs vs hugetlbfs] does not support the get_policy vm_op and the vma policy is null. This is incorrect for show_numa_maps() which is likely querying the numa_maps of some task other than current. Remove this fallback. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mempolicy: fix reference counting bugsLee Schermerhorn2008-03-101-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Address 3 known bugs in the current memory policy reference counting method. I have a series of patches to rework the reference counting to reduce overhead in the allocation path. However, that series will require testing in -mm once I repost it. 1) alloc_page_vma() does not release the extra reference taken for vma/shared mempolicy when the mode == MPOL_INTERLEAVE. This can result in leaking mempolicy structures. This is probably occurring, but not being noticed. Fix: add the conditional release of the reference. 2) hugezonelist unconditionally releases a reference on the mempolicy when mode == MPOL_INTERLEAVE. This can result in decrementing the reference count for system default policy [should have no ill effect] or premature freeing of task policy. If this occurred, the next allocation using task mempolicy would use the freed structure and probably BUG out. Fix: add the necessary check to the release. 3) The current reference counting method assumes that vma 'get_policy()' methods automatically add an extra reference a non-NULL returned mempolicy. This is true for shmem_get_policy() used by tmpfs mappings, including regular page shm segments. However, SHM_HUGETLB shm's, backed by hugetlbfs, just use the vma policy without the extra reference. This results in freeing of the vma policy on the first allocation, with reuse of the freed mempolicy structure on subsequent allocations. Fix: Rather than add another condition to the conditional reference release, which occur in the allocation path, just add a reference when returning the vma policy in shm_get_policy() to match the assumptions. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Greg KH <greg@kroah.com> Cc: Andi Kleen <ak@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Rientjes <rientjes@google.com> Cc: <eric.whitney@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: consolidate sem_exit_ns(), msg_exit_ns() and shm_exit_ns()Pierre Peiffer2008-02-081-21/+6
| | | | | | | | | | | | | | | | | | | | sem_exit_ns(), msg_exit_ns() and shm_exit_ns() are all called when an ipc_namespace is released to free all ipcs of each type. But in fact, they do the same thing: they loop around all ipcs to free them individually by calling a specific routine. This patch proposes to consolidate this by introducing a common function, free_ipcs(), that do the job. The specific routine to call on each individual ipcs is passed as parameter. For this, these ipc-specific 'free' routines are reworked to take a generic 'struct ipc_perm' as parameter. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: make struct ipc_ids static in ipc_namespacePierre Peiffer2008-02-081-22/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Each ipc_namespace contains a table of 3 pointers to struct ipc_ids (3 for msg, sem and shm, structure used to store all ipcs) These 'struct ipc_ids' are dynamically allocated for each icp_namespace as the ipc_namespace itself (for the init namespace, they are initialized with pointers to static variables instead) It is so for historical reason: in fact, before the use of idr to store the ipcs, the ipcs were stored in tables of variable length, depending of the maximum number of ipc allowed. Now, these 'struct ipc_ids' have a fixed size. As they are allocated in any cases for each new ipc_namespace, there is no gain of memory in having them allocated separately of the struct ipc_namespace. This patch proposes to make this table static in the struct ipc_namespace. Thus, we can allocate all in once and get rid of all the code needed to allocate and free these ipc_ids separately. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Acked-by: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* namespaces: move the IPC namespace under IPC_NS optionPavel Emelyanov2008-02-081-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the IPC namespace management code is spread over the ipc/*.c files. I moved this code into ipc/namespace.c file which is compiled out when needed. The linux/ipc_namespace.h file is used to store the prototypes of the functions in namespace.c and the stubs for NAMESPACES=n case. This is done so, because the stub for copy_ipc_namespace requires the knowledge of the CLONE_NEWIPC flag, which is in sched.h. But the linux/ipc.h file itself in included into many many .c files via the sys.h->sem.h sequence so adding the sched.h into it will make all these .c depend on sched.h which is not that good. On the other hand the knowledge about the namespaces stuff is required in 4 .c files only. Besides, this patch compiles out some auxiliary functions from ipc/sem.c, msg.c and shm.c files. It turned out that moving these functions into namespaces.c is not that easy because they use many other calls and macros from the original file. Moving them would make this patch complicated. On the other hand all these functions can be consolidated, so I will send a separate patch doing this a bit later. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: fix error check in all new xxx_lock() and xxx_exit_ns() functionsPierre Peiffer2008-02-061-3/+17
| | | | | | | | | | | | | | | | | | | | | | | | | In the new implementation of the [sem|shm|msg]_lock[_check]() routines, we use the return value of ipc_lock() in container_of() without any check. But ipc_lock may return a errcode. The use of this errcode in container_of() may alter this errcode, and we don't want this. And in xxx_exit_ns, the pointer return by idr_find is of type 'struct kern_ipc_per'... Today, the code will work as is because the member used in these container_of() is the first member of its container (offset == 0), the errcode isn't changed then. But in the general case, we can't count on this assumption and this may lead later to a real bug if we don't correct this. Again, the proposed solution is simple and correct. But, as pointed by Nadia, with this solution, the same check will be done several times (in all sub-callers...), what is not very funny/optimal... Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* IPC: fix error case when idr-cache is empty in ipcget()Pierre Peiffer2007-10-191-2/+3
| | | | | | | | | | | | | | | With the use of idr to store the ipc, the case where the idr cache is empty, when idr_get_new is called (this may happen even if we call idr_pre_get() before), is not well handled: it lets semget()/shmget()/msgget() return ENOSPC when this cache is empty, what 1. does not reflect the facts and 2. does not conform to the man(s). This patch fixes this by retrying the whole process of allocation in this case. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: remove unneeded parametersNadia Derbey2007-10-191-3/+2
| | | | | | | | | Remvoe the unneeded parameters from ipc_checkid() and ipc_buildid() interfaces. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fix idr_find() lockingNadia Derbey2007-10-191-26/+51
| | | | | | | | | | | | | | | | | | This is a patch that fixes the way idr_find() used to be called in ipc_lock(): in all the paths that don't imply an update of the ipcs idr, it was called without the idr tree being locked. The changes are: . in ipc_ids, the mutex has been changed into a reader/writer semaphore. . ipc_lock() now takes the mutex as a reader during the idr_find(). . a new routine ipc_lock_down() has been defined: it doesn't take the mutex, assuming that it is being held by the caller. This is the routine that is now called in all the update paths. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Acked-by: Jarek Poplawski <jarkao2@o2.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: fix wrong commentsNadia Derbey2007-10-191-13/+26
| | | | | | | | | This patch fixes the wrong / obsolete comments in the ipc code. Also adds a missing lock around ipc_get_maxid() in shm_get_stat(). Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Storing ipcs into IDRsNadia Derbey2007-10-191-6/+17
| | | | | | | | | | | | | | This patch converts casts of struct kern_ipc_perm to . struct msg_queue . struct sem_array . struct shmid_kernel into the equivalent container_of() macro. It improves code maintenance because the code need not change if kern_ipc_perm is no longer at the beginning of the containing struct. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: integrate ipc_checkid() into ipc_lock()Nadia Derbey2007-10-191-42/+48
| | | | | | | | | | | | This patch introduces a new ipc_lock_check() routine interface: . each time ipc_checkid() is called, this is done after calling ipc_lock(). ipc_checkid() is now called from inside ipc_lock_check(). [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: fix RCU locking] Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: remove the ipc_get() routineNadia Derbey2007-10-191-3/+13
| | | | | | | | | This is a trivial patch that removes the ipc_get() routine: it is replaced by a call to idr_find(). Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: unify the syscalls codeNadia Derbey2007-10-191-46/+27
| | | | | | | | | | This patch introduces a change into the sys_msgget(), sys_semget() and sys_shmget() routines: they now share a common code, which is better for maintainability. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: store ipcs into IDRsNadia Derbey2007-10-191-47/+69
| | | | | | | | | | | | | | | | | This patch introduces ipcs storage into IDRs. The main changes are: . This ipc_ids structure is changed: the entries array is changed into a root idr structure. . The grow_ary() routine is removed: it is not needed anymore when adding an ipc structure, since we are now using the IDR facility. . The ipc_rmid() routine interface is changed: . there is no need for this routine to return the pointer passed in as argument: it is now declared as a void . since the id is now part of the kern_ipc_perm structure, no need to have it as an argument to the routine Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pid namespaces: changes to show virtual ids to userPavel Emelyanov2007-10-191-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the largest patch in the set. Make all (I hope) the places where the pid is shown to or get from user operate on the virtual pids. The idea is: - all in-kernel data structures must store either struct pid itself or the pid's global nr, obtained with pid_nr() call; - when seeking the task from kernel code with the stored id one should use find_task_by_pid() call that works with global pids; - when showing pid's numerical value to the user the virtual one should be used, but however when one shows task's pid outside this task's namespace the global one is to be used; - when getting the pid from userspace one need to consider this as the virtual one and use appropriate task/pid-searching functions. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: nuther build fix] [akpm@linux-foundation.org: yet nuther build fix] [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* r/o bind mounts: filesystem helpers for custom 'struct file'sDave Hansen2007-10-171-8/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Why do we need r/o bind mounts? This feature allows a read-only view into a read-write filesystem. In the process of doing that, it also provides infrastructure for keeping track of the number of writers to any given mount. This has a number of uses. It allows chroots to have parts of filesystems writable. It will be useful for containers in the future because users may have root inside a container, but should not be allowed to write to somefilesystems. This also replaces patches that vserver has had out of the tree for several years. It allows security enhancement by making sure that parts of your filesystem read-only (such as when you don't trust your FTP server), when you don't want to have entire new filesystems mounted, or when you want atime selectively updated. I've been using the following script to test that the feature is working as desired. It takes a directory and makes a regular bind and a r/o bind mount of it. It then performs some normal filesystem operations on the three directories, including ones that are expected to fail, like creating a file on the r/o mount. This patch: Some filesystems forego the vfs and may_open() and create their own 'struct file's. This patch creates a couple of helper functions which can be used by these filesystems, and will provide a unified place which the r/o bind mount code may patch. Also, rename an existing, static-scope init_file() to a less generic name. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/shm.c: make 2 functions staticAdrian Bunk2007-10-171-2/+3
| | | | | | | | This patch makes two needlessly global functions static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix user struct leakage with locked IPC shem segmentPavel Emelianov2007-07-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When user locks an ipc shmem segmant with SHM_LOCK ctl and the segment is already locked the shmem_lock() function returns 0. After this the subsequent code leaks the existing user struct: == ipc/shm.c: sys_shmctl() == ... err = shmem_lock(shp->shm_file, 1, user); if (!err) { shp->shm_perm.mode |= SHM_LOCKED; shp->mlock_user = user; } ... == Other results of this are: 1. the new shp->mlock_user is not get-ed and will point to freed memory when the task dies. 2. the RLIMIT_MEMLOCK is screwed on both user structs. The exploit looks like this: == id = shmget(...); setresuid(uid, 0, 0); shmctl(id, SHM_LOCK, NULL); setresuid(uid + 1, 0, 0); shmctl(id, SHM_LOCK, NULL); == My solution is to return 0 to the userspace and do not change the segment's user. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* NOMMU: Fix SYSV IPC SHMDavid Howells2007-07-311-0/+2
| | | | | | | | | | Fix the SYSV IPC SHM to work with the changes applied by the new fault handler patches when CONFIG_MMU=n. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fault feedback #1Nick Piggin2007-07-191-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | Change ->fault prototype. We now return an int, which contains VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte. FAULT_RET_ code tells the VM whether a page was found, whether it has been locked, and potentially other things. This is not quite the way he wanted it yet, but that's changed in the next patch (which requires changes to arch code). This means we no longer set VM_CAN_INVALIDATE in the vma in order to say that a page is locked which requires filemap_nopage to go away (because we can no longer remain backward compatible without that flag), but we were going to do that anyway. struct fault_data is renamed to struct vm_fault as Linus asked. address is now a void __user * that we should firmly encourage drivers not to use without really good reason. The page is now returned via a page pointer in the vm_fault struct. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: merge populate and nopage into fault (fixes nonlinear)Nick Piggin2007-07-191-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes the virtual address -> file offset differently from linear mappings. ->populate is a layering violation because the filesystem/pagecache code should need to know anything about the virtual memory mapping. The hitch here is that the ->nopage handler didn't pass down enough information (ie. pgoff). But it is more logical to pass pgoff rather than have the ->nopage function calculate it itself anyway (because that's a similar layering violation). Having the populate handler install the pte itself is likewise a nasty thing to be doing. This patch introduces a new fault handler that replaces ->nopage and ->populate and (later) ->nopfn. Most of the old mechanism is still in place so there is a lot of duplication and nice cleanups that can be removed if everyone switches over. The rationale for doing this in the first place is that nonlinear mappings are subject to the pagefault vs invalidate/truncate race too, and it seemed stupid to duplicate the synchronisation logic rather than just consolidate the two. After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in pagecache. Seems like a fringe functionality anyway. NOPAGE_REFAULT is removed. This should be implemented with ->fault, and no users have hit mainline yet. [akpm@linux-foundation.org: cleanup] [randy.dunlap@oracle.com: doc. fixes for readahead] [akpm@linux-foundation.org: build fix] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove CONFIG_UTS_NS and CONFIG_IPC_NSCedric Le Goater2007-07-161-3/+1
| | | | | | | | | | | | | | CONFIG_UTS_NS and CONFIG_IPC_NS have very little value as they only deactivate the unshare of the uts and ipc namespaces and do not improve performance. Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Acked-by: "Serge E. Hallyn" <serue@us.ibm.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* shm: fix the filename of hugetlb sysv shared memoryEric W. Biederman2007-06-161-3/+3
| | | | | | | | | | | | | | | | | | | | | | Some user space tools need to identify SYSV shared memory when examining /proc/<pid>/maps. To do so they look for a block device with major zero, a dentry named SYSV<sysv key>, and having the minor of the internal sysv shared memory kernel mount. To help these tools and to make it easier for people just browsing /proc/<pid>/maps this patch modifies hugetlb sysv shared memory to use the SYSV<key> dentry naming convention. User space tools will still have to be aware that hugetlb sysv shared memory lives on a different internal kernel mount and so has a different block device minor number from the rest of sysv shared memory. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Albert Cahalan <acahalan@gmail.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: fix get_policy for stacked shared memory filesAdam Litke2007-06-161-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here's another breakage as a result of shared memory stacked files :( The NUMA policy for a VMA is determined by checking the following (in the order given): 1) vma->vm_ops->get_policy() (if defined) 2) vma->vm_policy (if defined) 3) task->mempolicy (if defined) 4) Fall back to default_policy By switching to stacked files for shared memory, get_policy() is now always set to shm_get_policy which is a wrapper function. This causes us to stop at step 1, which yields NULL for hugetlb instead of task->mempolicy which was the previous (and correct) result. This patch modifies the shm_get_policy() wrapper to maintain steps 1-3 for the wrapped vm_ops. (akpm: the refcounting of mempolicies is busted and this patch does nothing to improve it) Signed-off-by: Adam Litke <agl@us.ibm.com> Acked-by: William Irwin <bill.irwin@oracle.com> Cc: dean gaudet <dean@arctic.org> Cc: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Restore shmid as inode# to fix /proc/pid/maps ABI breakageBadari Pulavarty2007-06-161-0/+5
| | | | | | | | | | | | | shmid used to be stored as inode# for shared memory segments. Some of the proc-ps tools use this from /proc/pid/maps. Recent cleanups to newseg() changed it. This patch sets inode number back to shared memory id to fix breakage. Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Cc: "Albert Cahalan" <acahalan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Fix get_unmapped_area and fsync for hugetlb shm segmentsAdam Litke2007-03-011-6/+26
| | | | | | | | | | | | | | | | | | | | This patch provides the following hugetlb-related fixes to the recent stacked shm files changes: - Update is_file_hugepages() so it will reconize hugetlb shm segments. - get_unmapped_area must be called with the nested file struct to handle the sfd->file->f_ops->get_unmapped_area == NULL case. - The fsync f_op must be wrapped since it is specified in the hugetlbfs f_ops. This is based on proposed fixes from Eric Biederman that were debugged and tested by me. Without it, attempting to use hugetlb shared memory segments on powerpc (and likely ia64) will kill your box. Signed-off-by: Adam Litke <agl@us.ibm.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: William Irwin <bill.irwin@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] make ipc/shm.c:shm_nopage() staticAdrian Bunk2007-03-011-2/+2
| | | | | | | | | shm_nopage() can become static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] shm: make sysv ipc shared memory use stacked filesEric W. Biederman2007-02-201-85/+155
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current ipc shared memory code runs into several problems because it does not quite use files like the rest of the kernel. With the option of backing ipc shared memory with either hugetlbfs or ordinary shared memory the problems got worse. With the added support for ipc namespaces things behaved so unexpected that we now have several bad namespace reference counting bugs when using what appears at first glance to be a reasonable idiom. So to attack these problems and hopefully make the code more maintainable this patch simply uses the files provided by other parts of the kernel and builds it's own files out of them. The shm files are allocated in do_shmat and freed when their reference count drops to zero with their last unmap. The file and vm operations that we don't want to implement or we don't implement completely we just delegate to the operations of our backing file. This means that we now get an accurate shm_nattch count for we have a hugetlbfs inode for backing store, and the shm accounting of last attach and last detach time work as well. This means that getting a reference to the ipc namespace when we create the file and dropping the referenece in the release method is now safe and correct. This means we no longer need a special case for clearing VM_MAYWRITE as our file descriptor now only has write permissions when we have requested write access when calling shmat. Although VM_SHARED is now cleared as well which I believe is harmless and is mostly likely a minor bug fix. By using the same set of operations for both the hugetlb case and regular shared memory case shmdt is not simplified and made slightly more correct as now the test "vma->vm_ops == &shm_vm_ops" is 100% accurate in spotting all shared memory regions generated from sysvipc shared memory. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] mark struct file_operations const 7Arjan van de Ven2007-02-121-2/+2
| | | | | | | | | | | Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] correct sys_shmget allocation checkGuy Streeter2007-01-231-1/+1
| | | | | | | | | As written, sys_shmget will return ENOSPC when one page is still available for allocation. This patch corrects the test. Signed-off-by: Guy Streeter <guy.streeter+lkml@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --
* [PATCH] struct path: convert ipcJosef Sipek2006-12-081-8/+8
| | | | | | Signed-off-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix ipc entries removalPavel Emelianov2006-11-031-0/+1
| | | | | | | | | | | | | | | | | | | | Fix two issuses related to ipc_ids->entries freeing. 1. When freeing ipc namespace we need to free entries allocated with ipc_init_ids(). 2. When removing old entries in grow_ary() ipc_rcu_putref() may be called on entries set to &ids->nullentry earlier in ipc_init_ids(). This is almost impossible without namespaces, but with them this situation becomes possible. Found during OpenVZ testing after obvious leaks in beancounters. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Cc: Kirill Korotaev <dev@openvz.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] IPC namespace - shmKirill Korotaev2006-10-021-86/+168
| | | | | | | | | IPC namespace support for IPC shm code. Signed-off-by: Pavel Emelianiov <xemul@openvz.org> Signed-off-by: Kirill Korotaev <dev@openvz.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-301-1/+0
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] remove unused o_flags from do_shmatHugh Dickins2006-06-231-3/+0
| | | | | | | | Remove the unused variable o_flags from do_shmat. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] update of IPC audit record cleanupLinda Knippers2006-06-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following patch addresses most of the issues with the IPC_SET_PERM records as described in: https://www.redhat.com/archives/linux-audit/2006-May/msg00010.html and addresses the comments I received on the record field names. To summarize, I made the following changes: 1. Changed sys_msgctl() and semctl_down() so that an IPC_SET_PERM record is emitted in the failure case as well as the success case. This matches the behavior in sys_shmctl(). I could simplify the code in sys_msgctl() and semctl_down() slightly but it would mean that in some error cases we could get an IPC_SET_PERM record without an IPC record and that seemed odd. 2. No change to the IPC record type, given no feedback on the backward compatibility question. 3. Removed the qbytes field from the IPC record. It wasn't being set and when audit_ipc_obj() is called from ipcperms(), the information isn't available. If we want the information in the IPC record, more extensive changes will be necessary. Since it only applies to message queues and it isn't really permission related, it doesn't seem worth it. 4. Removed the obj field from the IPC_SET_PERM record. This means that the kern_ipc_perm argument is no longer needed. 5. Removed the spaces and renamed the IPC_SET_PERM field names. Replaced iuid and igid fields with ouid and ogid in the IPC record. I tested this with the lspp.22 kernel on an x86_64 box. I believe it applies cleanly on the latest kernel. -- ljk Signed-off-by: Linda Knippers <linda.knippers@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] Rework of IPC auditingSteve Grubb2006-05-011-3/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1) The audit_ipc_perms() function has been split into two different functions: - audit_ipc_obj() - audit_ipc_set_perm() There's a key shift here... The audit_ipc_obj() collects the uid, gid, mode, and SElinux context label of the current ipc object. This audit_ipc_obj() hook is now found in several places. Most notably, it is hooked in ipcperms(), which is called in various places around the ipc code permforming a MAC check. Additionally there are several places where *checkid() is used to validate that an operation is being performed on a valid object while not necessarily having a nearby ipcperms() call. In these locations, audit_ipc_obj() is called to ensure that the information is captured by the audit system. The audit_set_new_perm() function is called any time the permissions on the ipc object changes. In this case, the NEW permissions are recorded (and note that an audit_ipc_obj() call exists just a few lines before each instance). 2) Support for an AUDIT_IPC_SET_PERM audit message type. This allows for separate auxiliary audit records for normal operations on an IPC object and permissions changes. Note that the same struct audit_aux_data_ipcctl is used and populated, however there are separate audit_log_format statements based on the type of the message. Finally, the AUDIT_IPC block of code in audit_free_aux() was extended to handle aux messages of this new type. No more mem leaks I hope ;-) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] shmat: stop mprotect from giving write permission to a readonly ↵Hugh Dickins2006-04-171-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | attachment (CVE-2006-1524) I found that all of 2.4 and 2.6 have been letting mprotect give write permission to a readonly attachment of shared memory, whether or not IPC would give the caller that permission. SUS says "The behaviour of this function [mprotect] is unspecified if the mapping was not established by a call to mmap", but I don't think we can interpret that as allowing it to subvert IPC permissions. I haven't tried 2.2, but the 2.2.26 source looks like it gets it right; and the patch below reproduces that behaviour - mprotect cannot be used to add write permission to a shared memory segment attached readonly. This patch is simple, and I'm sure it's what we should have done in 2.4.0: if you want to go on to switch write permission on and off with mprotect, just don't attach the segment readonly in the first place. However, we could have accumulated apps which attach readonly (even though they would be permitted to attach read/write), and which subsequently use mprotect to switch write permission on and off: it's not unreasonable. I was going to add a second ipcperms check in do_shmat, to check for writable when readonly, and if not writable find_vma and clear VM_MAYWRITE. But security_ipc_permission might do auditing, and it seems wrong to report an attempt for write permission when there has been none. Or we could flag the vma as SHM, note the shmid or shp in vm_private_data, and then get mprotect to check. But the patch below is a lot simpler: I'd rather stick with it, if we can convince ourselves somehow that it'll be safe. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* BUG_ON() Conversion in ipc/shm.cEric Sesterhenn2006-04-021-8/+7
| | | | | | | | this changes if() BUG(); constructs to BUG_ON() which is cleaner, contains unlikely() and can better optimized away. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
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