28 Apr, 2008
2 commits
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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
Cc: Christoph Lameter
Cc: David Rientjes
Cc: Mel Gorman
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Cc: Christoph Lameter
Cc: David Rientjes
Cc: Mel Gorman
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Apr, 2008
2 commits
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This is the first really tricky patch in the series. It elevates the writer
count on a mount each time a non-special file is opened for write.We used to do this in may_open(), but Miklos pointed out that __dentry_open()
is used as well to create filps. This will cover even those cases, while a
call in may_open() would not have.There is also an elevated count around the vfs_create() call in open_namei().
See the comments for more details, but we need this to fix a 'create, remount,
fail r/w open()' race.Some filesystems forego the use of normal vfs calls to create
struct files. Make sure that these users elevate the mnt
writer count because they will get __fput(), and we need
to make sure they're balanced.Acked-by: Al Viro
Signed-off-by: Christoph Hellwig
Signed-off-by: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro -
Elevate the write count during the vfs_rmdir() and vfs_unlink().
[AV: merged rmdir and unlink parts, added missing pieces in nfsd]
Acked-by: Serge Hallyn
Acked-by: Al Viro
Signed-off-by: Christoph Hellwig
Signed-off-by: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Al Viro
11 Mar, 2008
1 commit
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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
Cc: Greg KH
Cc: Andi Kleen
Cc: Christoph Lameter
Cc: Mel Gorman
Cc: David Rientjes
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 Feb, 2008
7 commits
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When sending the pid namespaces patches I wrongly converted the tsk->tgid into
task_pid_vnr(tsk) in mqueue-s (the git id of this patch is
b488893a390edfe027bae7a46e9af8083e740668).The proper behavior is to get the task_tgid_vnr(tsk).
This seem to be the only mistake of that kind.
Signed-off-by: Pavel Emelyanov
Cc: "Eric W. Biederman"
Cc: Oleg Nesterov
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Some time ago the xxx_vnr() calls (e.g. pid_vnr or find_task_by_vpid) were
_all_ converted to operate on the current pid namespace. After this each call
like xxx_nr_ns(foo, current->nsproxy->pid_ns) is nothing but a xxx_vnr(foo)
one.Switch all the xxx_nr_ns() callers to use the xxx_vnr() calls where
appropriate.Signed-off-by: Pavel Emelyanov
Reviewed-by: Oleg Nesterov
Cc: "Eric W. Biederman"
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Cc: Cedric Le Goater
Cc: Pavel Emelyanov
Cc: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Acked-by: Cedric Le Goater
Cc: Pavel Emelyanov
Cc: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
These commands (SEM_STAT and IPC_STAT) are rather doing the same things
(only the meaning of the id given as input and the return value differ).
However, for the semaphores, they are handled in two different places (two
different functions).This patch consolidates this for clarification by handling these both
commands in the same place in semctl_nolock(). It also removes one unused
parameter for this function.Signed-off-by: Pierre Peiffer
Cc: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
ipc_lock_check_down(), ipc_lock_check() and ipcget() seem too large to be
inline. Besides, they give no optimization being inline as they perform
calls inside in any case.Moving them into ipc/util.c saves 500 bytes of vmlinux and shortens IPC
internal API.$ ./scripts/bloat-o-meter vmlinux-orig vmlinux
add/remove: 3/2 grow/shrink: 0/10 up/down: 490/-989 (-499)
function old new delta
ipcget - 392 +392
ipc_lock_check_down - 49 +49
ipc_lock_check - 49 +49
sys_semget 119 105 -14
sys_shmget 108 86 -22
sys_msgget 100 78 -22
do_msgsnd 665 631 -34
do_msgrcv 680 644 -36
do_shmat 771 733 -38
sys_msgctl 1302 1229 -73
ipcget_new 80 - -80
sys_semtimedop 1534 1452 -82
sys_semctl 2034 1922 -112
sys_shmctl 1919 1765 -154
ipcget_public 322 - -322The ipcget() growth is the result of gcc inlining of currently static
ipcget_new/_public.Signed-off-by: Pavel Emelyanov
Cc: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Acked-by: Serge Hallyn
Cc: Cedric Le Goater
Cc: "Eric W. Biederman"
Cc: Herbert Poetzl
Cc: Kirill Korotaev
Cc: Sukadev Bhattiprolu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 Feb, 2008
2 commits
-
sysvipc_find_ipc() can become static.
Signed-off-by: Adrian Bunk
Acked-by: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Cc: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Nov, 2007
1 commit
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The error path in sys_mq_getsetattr() after the call to
audit_mq_getsetattr() is wrong - the info->lock is not unlocked and the
struct file *filp is not put.Fix them both.
Signed-off-by: Pavel Emelyanov
Cc: Pierre Peiffer
Cc: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 Nov, 2007
1 commit
-
Commit ed6dcf4a in the history.git tree broke netlink_unicast timeouts
by moving the schedule_timeout() call to a new function that doesn't
propagate the remaining timeout back to the caller. This means on each
retry we start with the full timeout again.ipc/mqueue.c seems to actually want to wait indefinitely so this
behaviour is retained.Signed-off-by: Patrick McHardy
Signed-off-by: David S. Miller
21 Oct, 2007
1 commit
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makes caller simpler *and* allows to scan ancestors
Signed-off-by: Al Viro
20 Oct, 2007
14 commits
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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
Cc: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Virtualization of sysv msg queues is incomplete: msg_hdrs and msg_bytes
variables visible from userspace are global. Let's make them
per-namespace.Signed-off-by: Alexey Kuznetsov
Signed-off-by: Kirill Korotaev
Cc: Pierre Peiffer
Cc: Nadia Derbey
Cc: Serge Hallyn
Acked-by: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Some comments about sem_undo_list seem wrong.
About the comment above unlock_semundo:
"... If task2 now exits before task1 releases the lock (by calling
unlock_semundo()), then task1 will never call spin_unlock(). ..."This is just wrong, I see no reason for which task1 will not call
spin_unlock... The rest of this comment is also wrong... Unless I
miss something (of course).Finally, (un)lock_semundo functions are useless, so remove them
for simplification. (this avoids an useless if statement)Signed-off-by: Pierre Peiffer
Cc: Nadia Derbey
Acked-by: Serge Hallyn
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remvoe the unneeded parameters from ipc_checkid() and ipc_buildid()
interfaces.Signed-off-by: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Acked-by: Jarek Poplawski
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This is a trivial patch that changes the ipc_buildid() routine into a static
inline.Signed-off-by: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This is a trivial patch that changes all the (id % SEQ_MULTIPLIER) into a call
to the ipcid_to_idx(id) macro.Signed-off-by: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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 routineSigned-off-by: Nadia Derbey
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Signed-off-by: Alexey Dobriyan
Cc: Sukadev Bhattiprolu
Cc: Oleg Nesterov
Cc: Paul Menage
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Oct, 2007
1 commit
-
Because of a conflict with FS_INODE_NR none of the binary sysctl numbers use
by mqueue, were available to user space. So just remove them.Signed-off-by: Eric W. Biederman
Cc: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Oct, 2007
4 commits
-
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
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Finish the work : kill all #ifdef CONFIG_IPC_NS.
Thanks Robert !
Signed-off-by: Cedric Le Goater
Cc: Eric Biederman
Cc: Robert P. J. Day
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch makes two needlessly global functions static.
Signed-off-by: Adrian Bunk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Slab constructors currently have a flags parameter that is never used. And
the order of the arguments is opposite to other slab functions. The object
pointer is placed before the kmem_cache pointer.Convert
ctor(void *object, struct kmem_cache *s, unsigned long flags)
to
ctor(struct kmem_cache *s, void *object)
throughout the kernel
[akpm@linux-foundation.org: coupla fixes]
Signed-off-by: Christoph Lameter
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Oct, 2007
1 commit
-
netlink_sendskb does not use third argument. Clean it and save a couple of
bytes.Signed-off-by: Denis V. Lunev
Acked-by: Alexey Kuznetsov
Signed-off-by: David S. Miller
01 Aug, 2007
2 commits
-
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
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
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
Cc: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Jul, 2007
1 commit
-
Slab destructors were no longer supported after Christoph's
c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been
BUGs for both slab and slub, and slob never supported them
either.This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).Signed-off-by: Paul Mundt
