23 Jan, 2016
1 commit
-
There are many locations that do
if (memory_was_allocated_by_vmalloc)
vfree(ptr);
else
kfree(ptr);but kvfree() can handle both kmalloc()ed memory and vmalloc()ed memory
using is_vmalloc_addr(). Unless callers have special reasons, we can
replace this branch with kvfree(). Please check and reply if you found
problems.Signed-off-by: Tetsuo Handa
Acked-by: Michal Hocko
Acked-by: Jan Kara
Acked-by: Russell King
Reviewed-by: Andreas Dilger
Acked-by: "Rafael J. Wysocki"
Acked-by: David Rientjes
Cc: "Luck, Tony"
Cc: Oleg Drokin
Cc: Boris Petkov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Oct, 2015
1 commit
-
As reported by Dmitry Vyukov, we really shouldn't do ipc_addid() before
having initialized the IPC object state. Yes, we initialize the IPC
object in a locked state, but with all the lockless RCU lookup work,
that IPC object lock no longer means that the state cannot be seen.We already did this for the IPC semaphore code (see commit e8577d1f0329:
"ipc/sem.c: fully initialize sem_array before making it visible") but we
clearly forgot about msg and shm.Reported-by: Dmitry Vyukov
Cc: Manfred Spraul
Cc: Davidlohr Bueso
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds
01 Jul, 2015
4 commits
-
In ipc_obtain_object_check we return -EIDRM when a bogus sequence number
is detected via ipc_checkid, while the ipc manpages state the following
return codes for such errors:EIDRM points to a removed identifier.
EINVAL Invalid value, or unaligned, etc.EIDRM should only be returned upon a RMID call (->deleted check), and thus
return EINVAL for wrong seq. This difference in semantics has also caused
real bugs, ie: https://bugzilla.redhat.com/show_bug.cgi?id=246509Signed-off-by: Davidlohr Bueso
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The ipc_lock helper is used by all forms of sysv ipc to acquire the ipc
object's spinlock. Upon error (bogus identifier), we always return
-EINVAL, whether the problem be in the idr path or because we raced with a
task performing RMID. For the later, however, all ipc related manpages,
state the that for:EIDRM points to a removed identifier.
And return:
EINVAL Invalid value, or unaligned, etc.
Which (EINVAL) should only return once the ipc resource is deleted. For
all types of ipc this is done immediately upon a RMID command. However,
shared memory behaves slightly different as it can merely mark a segment
for deletion, and delay the actual freeing until there are no more active
consumers. Per shmctl(IPC_RMID) manpage:""
Mark the segment to be destroyed. The segment will only actually
be destroyed after the last process detaches it (i.e., when the
shm_nattch member of the associated structure shmid_ds is zero).
""Unlike ipc_lock, paths that behave "correctly", at least per the manpage,
involve controlling the ipc resource via *ctl(), doing the exact same
validity check as ipc_lock after right acquiring the spinlock:if (!ipc_valid_object()) {
err = -EIDRM;
goto out_unlock;
}Thus make ipc_lock consistent with the rest of ipc code and return -EIDRM
in ipc_lock when !ipc_valid_object().Signed-off-by: Davidlohr Bueso
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
... to ipc_obtain_object_idr, which is more meaningful and makes the code
slightly easier to follow.Signed-off-by: Davidlohr Bueso
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use kvfree() instead of open-coding it.
Signed-off-by: Pekka Enberg
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Apr, 2015
1 commit
-
The seq_printf return value, because it's frequently misused,
will eventually be converted to void.See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to
seq_has_overflowed() and make public")Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Dec, 2014
1 commit
-
SysV can be abused to allocate locked kernel memory. For most systems, a
small limit doesn't make sense, see the discussion with regards to SHMMAX.Therefore: increase MSGMNI to the maximum supported.
And: If we ignore the risk of locking too much memory, then an automatic
scaling of MSGMNI doesn't make sense. Therefore the logic can be removed.The code preserves auto_msgmni to avoid breaking any user space applications
that expect that the value exists.Notes:
1) If an administrator must limit the memory allocations, then he can set
MSGMNI as necessary.Or he can disable sysv entirely (as e.g. done by Android).
2) MSGMAX and MSGMNB are intentionally not increased, as these values are used
to control latency vs. throughput:
If MSGMNB is large, then msgsnd() just returns and more messages can be queued
before a task switch to a task that calls msgrcv() is forced.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Manfred Spraul
Cc: Davidlohr Bueso
Cc: Rafael Aquini
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Oct, 2014
1 commit
-
Using __seq_open_private() removes boilerplate code from
sysvipc_proc_open().The resultant code is shorter and easier to follow.
However, please note that __seq_open_private() call kzalloc() rather than
kmalloc() which may affect timing due to the memory initialisation
overhead.Signed-off-by: Rob Jones
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 Sep, 2014
1 commit
-
This patch fix spelling typo found in DocBook/kernel-api.xml.
It is because the file is generated from the source comments,
I have to fix the comments in source codes.Signed-off-by: Masanari Iida
Acked-by: Randy Dunlap
Signed-off-by: Jiri Kosina
07 Jun, 2014
2 commits
-
trailing whitespace
Signed-off-by: Paul McQuade
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There is no need to recreate the very same ipc_ops structure on every
kernel entry for msgget/semget/shmget. Just declare it static and be
done with it. While at it, constify it as we don't modify the structure
at runtime.Found in the PaX patch, written by the PaX Team.
Signed-off-by: Mathias Krause
Cc: PaX Team
Cc: Davidlohr Bueso
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Apr, 2014
1 commit
-
... since __initcall is now deprecated.
Signed-off-by: Davidlohr Bueso
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Jan, 2014
7 commits
-
This field is only used to reset the ids seq number if it exceeds the
smaller of INT_MAX/SEQ_MULTIPLIER and USHRT_MAX, and can therefore be
moved out of the structure and into its own macro. Since each
ipc_namespace contains a table of 3 pointers to struct ipc_ids we can
save space in instruction text:text data bss dec hex filename
56232 2348 24 58604 e4ec ipc/built-in.o
56216 2348 24 58588 e4dc ipc/built-in.o-afterSigned-off-by: Davidlohr Bueso
Reviewed-by: Jonathan Gonzalez
Cc: Aswin Chandramouleeswaran
Cc: Rik van Riel
Acked-by: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Get rid of silly/useless label jumping.
Signed-off-by: Davidlohr Bueso
Cc: Aswin Chandramouleeswaran
Cc: Rik van Riel
Acked-by: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Only found in ipc_rmid().
Signed-off-by: Davidlohr Bueso
Cc: Aswin Chandramouleeswaran
Cc: Rik van Riel
Acked-by: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Deal with checkpatch messages:
WARNING: braces {} are not necessary for single statement blocksSigned-off-by: Davidlohr Bueso
Cc: Aswin Chandramouleeswaran
Cc: Rik van Riel
Acked-by: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
IPC commenting style is all over the place, *specially* in util.c. This
patch orders things a bit.Signed-off-by: Davidlohr Bueso
Cc: Aswin Chandramouleeswaran
Cc: Rik van Riel
Acked-by: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The ipc code does not adhere the typical linux coding style.
This patch fixes lots of simple whitespace errors.- mostly autogenerated by
scripts/checkpatch.pl -f --fix \
--types=pointer_location,spacing,space_before_tab
- one manual fixup (keep structure members tab-aligned)
- removal of additional space_before_tab that were not found by --fixTested with some of my msg and sem test apps.
Andrew: Could you include it in -mm and move it towards Linus' tree?
Signed-off-by: Manfred Spraul
Suggested-by: Li Bin
Cc: Joe Perches
Acked-by: Rafael Aquini
Cc: Davidlohr Bueso
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
struct kern_ipc_perm.deleted is meant to be used as a boolean toggle, and
the changes introduced by this patch are just to make the case explicit.Signed-off-by: Rafael Aquini
Reviewed-by: Rik van Riel
Cc: Greg Thelen
Acked-by: Davidlohr Bueso
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Nov, 2013
1 commit
-
Remove unnecessary work pending test before calling schedule_work(). It
has been tested in queue_work_on() already. No functional changed.Signed-off-by: Xie XiuQi
Cc: Tejun Heo
Reviewed-by: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Oct, 2013
1 commit
-
The initial documentation was a bit incomplete, update accordingly.
[akpm@linux-foundation.org: make it more readable in 80 columns]
Signed-off-by: Davidlohr Bueso
Acked-by: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Sep, 2013
1 commit
-
Currently, IPC mechanisms do security and auditing related checks under
RCU. However, since security modules can free the security structure,
for example, through selinux_[sem,msg_queue,shm]_free_security(), we can
race if the structure is freed before other tasks are done with it,
creating a use-after-free condition. Manfred illustrates this nicely,
for instance with shared mem and selinux:-> do_shmat calls rcu_read_lock()
-> do_shmat calls shm_object_check().
Checks that the object is still valid - but doesn't acquire any locks.
Then it returns.
-> do_shmat calls security_shm_shmat (e.g. selinux_shm_shmat)
-> selinux_shm_shmat calls ipc_has_perm()
-> ipc_has_perm accesses ipc_perms->securityshm_close()
-> shm_close acquires rw_mutex & shm_lock
-> shm_close calls shm_destroy
-> shm_destroy calls security_shm_free (e.g. selinux_shm_free_security)
-> selinux_shm_free_security calls ipc_free_security(&shp->shm_perm)
-> ipc_free_security calls kfree(ipc_perms->security)This patch delays the freeing of the security structures after all RCU
readers are done. Furthermore it aligns the security life cycle with
that of the rest of IPC - freeing them based on the reference counter.
For situations where we need not free security, the current behavior is
kept. Linus states:"... the old behavior was suspect for another reason too: having the
security blob go away from under a user sounds like it could cause
various other problems anyway, so I think the old code was at least
_prone_ to bugs even if it didn't have catastrophic behavior."I have tested this patch with IPC testcases from LTP on both my
quad-core laptop and on a 64 core NUMA server. In both cases selinux is
enabled, and tests pass for both voluntary and forced preemption models.
While the mentioned races are theoretical (at least no one as reported
them), I wanted to make sure that this new logic doesn't break anything
we weren't aware of.Suggested-by: Linus Torvalds
Signed-off-by: Davidlohr Bueso
Acked-by: Manfred Spraul
Signed-off-by: Linus Torvalds
12 Sep, 2013
5 commits
-
No remaining users, we now use ipc_obtain_object_check().
Signed-off-by: Davidlohr Bueso
Cc: Sedat Dilek
Cc: Rik van Riel
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
After previous cleanups and optimizations, this function is no longer
heavily used and we don't have a good reason to keep it. Update the few
remaining callers and get rid of it.Signed-off-by: Davidlohr Bueso
Cc: Sedat Dilek
Cc: Rik van Riel
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
As suggested by Andrew, add a generic initial locking scheme used
throughout all sysv ipc mechanisms. Documenting the ids rwsem, how rcu
can be enough to do the initial checks and when to actually acquire the
kern_ipc_perm.lock spinlock.I found that adding it to util.c was generic enough.
Signed-off-by: Davidlohr Bueso
Tested-by: Sedat Dilek
Cc: Rik van Riel
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Since in some situations the lock can be shared for readers, we shouldn't
be calling it a mutex, rename it to rwsem.Signed-off-by: Davidlohr Bueso
Tested-by: Sedat Dilek
Cc: Rik van Riel
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that sem, msgque and shm, through *_down(), all use the lockless
variant of ipcctl_pre_down(), go ahead and delete it.[akpm@linux-foundation.org: fix function name in kerneldoc, cleanups]
Signed-off-by: Davidlohr Bueso
Tested-by: Sedat Dilek
Cc: Rik van Riel
Cc: Manfred Spraul
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Jul, 2013
3 commits
-
Enforce that ipc_rcu_alloc returns a cacheline aligned pointer on SMP.
Rationale:
The SysV sem code tries to move the main spinlock into a seperate
cacheline (____cacheline_aligned_in_smp). This works only if
ipc_rcu_alloc returns cacheline aligned pointers. vmalloc and kmalloc
return cacheline algined pointers, the implementation of ipc_rcu_alloc
breaks that.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Manfred Spraul
Cc: Rik van Riel
Cc: Davidlohr Bueso
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This function currently acquires both the rw_mutex and the rcu lock on
successful lookups, leaving the callers to explicitly unlock them,
creating another two level locking situation.Make the callers (including those that still use ipcctl_pre_down())
explicitly lock and unlock the rwsem and rcu lock.Signed-off-by: Davidlohr Bueso
Cc: Andi Kleen
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patchset continues the work that began in the sysv ipc semaphore
scaling series, seehttps://lkml.org/lkml/2013/3/20/546
Just like semaphores used to be, sysv shared memory and msg queues also
abuse the ipc lock, unnecessarily holding it for operations such as
permission and security checks.This patchset mostly deals with mqueues, and while shared mem can be
done in a very similar way, I want to get these patches out in the open
first. It also does some pending cleanups, mostly focused on the two
level locking we have in ipc code, taking care of ipc_addid() and
ipcctl_pre_down_nolock() - yes there are still functions that need to be
updated as well.This patch:
Make all callers explicitly take and release the RCU read lock.
This addresses the two level locking seen in newary(), newseg() and
newqueue(). For the last two, explicitly unlock the ipc object and the
rcu lock, instead of calling the custom shm_unlock and msg_unlock
functions. The next patch will deal with the open coded locking for
->perm.lockSigned-off-by: Davidlohr Bueso
Cc: Andi Kleen
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 May, 2013
2 commits
-
Commit 32fcfd40715e ("make vfree() safe to call from interrupt
contexts") made it safe to do vfree directly from the RCU callback,
which allows us to simplify ipc/util.c a lot by getting rid of the
differences between vmalloc/kmalloc memory.Signed-off-by: Al Viro
Signed-off-by: Linus Torvalds -
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
01 May, 2013
3 commits
-
Introduce finer grained locking for semtimedop, to handle the common case
of a program wanting to manipulate one semaphore from an array with
multiple semaphores.If the call is a semop manipulating just one semaphore in an array with
multiple semaphores, only take the lock for that semaphore itself.If the call needs to manipulate multiple semaphores, or another caller is
in a transaction that manipulates multiple semaphores, the sem_array lock
is taken, as well as all the locks for the individual semaphores.On a 24 CPU system, performance numbers with the semop-multi
test with N threads and N semaphores, look like this:vanilla Davidlohr's Davidlohr's + Davidlohr's +
threads patches rwlock patches v3 patches
10 610652 726325 1783589 2142206
20 341570 365699 1520453 1977878
30 288102 307037 1498167 2037995
40 290714 305955 1612665 2256484
50 288620 312890 1733453 2650292
60 289987 306043 1649360 2388008
70 291298 306347 1723167 2717486
80 290948 305662 1729545 2763582
90 290996 306680 1736021 2757524
100 292243 306700 1773700 3059159[davidlohr.bueso@hp.com: do not call sem_lock when bogus sma]
[davidlohr.bueso@hp.com: make refcounter atomic]
Signed-off-by: Rik van Riel
Suggested-by: Linus Torvalds
Acked-by: Davidlohr Bueso
Cc: Chegu Vinod
Cc: Jason Low
Reviewed-by: Michel Lespinasse
Cc: Peter Hurley
Cc: Stanislav Kinsbursky
Tested-by: Emmanuel Benisty
Tested-by: Sedat Dilek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Various forms of ipc use ipcctl_pre_down() to retrieve an ipc object and
check permissions, mostly for IPC_RMID and IPC_SET commands.Introduce ipcctl_pre_down_nolock(), a lockless version of this function.
The locking version is retained, yet modified to call the nolock version
without affecting its semantics, thus transparent to all ipc callers.Signed-off-by: Davidlohr Bueso
Signed-off-by: Rik van Riel
Suggested-by: Linus Torvalds
Cc: Chegu Vinod
Cc: Emmanuel Benisty
Cc: Jason Low
Cc: Michel Lespinasse
Cc: Peter Hurley
Cc: Stanislav Kinsbursky
Tested-by: Sedat Dilek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Through ipc_lock() and therefore ipc_lock_check() we currently return the
locked ipc object. This is not necessary for all situations and can,
therefore, cause unnecessary ipc lock contention.Introduce analogous ipc_obtain_object() and ipc_obtain_object_check()
functions that only lookup and return the ipc object.Both these functions must be called within the RCU read critical section.
[akpm@linux-foundation.org: propagate the ipc_obtain_object() errno from ipc_lock()]
Signed-off-by: Davidlohr Bueso
Signed-off-by: Rik van Riel
Reviewed-by: Chegu Vinod
Acked-by: Michel Lespinasse
Cc: Emmanuel Benisty
Cc: Jason Low
Cc: Peter Hurley
Cc: Stanislav Kinsbursky
Tested-by: Sedat Dilek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Apr, 2013
1 commit
-
Squishes a statement-with-no-effect warning, removes some ifdefs and
shrinks .text by one byte!Note that this code fails to check for blocking_notifier_chain_register()
failures.Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Apr, 2013
1 commit
-
The only part of proc_dir_entry the code outside of fs/proc
really cares about is PDE(inode)->data. Provide a helper
for that; static inline for now, eventually will be moved
to fs/proc, along with the knowledge of struct proc_dir_entry
layout.Signed-off-by: Al Viro
28 Feb, 2013
1 commit
-
Convert to the much saner new idr interface.
The new interface doesn't directly translate to the way idr_pre_get()
was used around ipc_addid() as preloading disables preemption. From
my cursory reading, it seems like we should be able to do all
allocation from ipc_addid(), so I moved it there. Can you please
check whether this would be okay? If this is wrong and ipc_addid()
should be allowed to be called from non-sleepable context, I'd suggest
allocating id itself in the outer functions and later install the
pointer using idr_replace().Signed-off-by: Tejun Heo
Reported-by: Sedat Dilek
Tested-by: Sedat Dilek
Cc: Stanislav Kinsbursky
Cc: "Eric W. Biederman"
Cc: James Morris
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Jan, 2013
1 commit
-
Add 3 new variables and sysctls to tune them (by one "next_id" variable
for messages, semaphores and shared memory respectively). This variable
can be used to set desired id for next allocated IPC object. By default
it's equal to -1 and old behaviour is preserved. If this variable is
non-negative, then desired idr will be extracted from it and used as a
start value to search for free IDR slot.Notes:
1) this patch doesn't guarantee that the new object will have desired
id. So it's up to user space how to handle new object with wrong id.2) After a sucessful id allocation attempt, "next_id" will be set back
to -1 (if it was non-negative).[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Stanislav Kinsbursky
Cc: Serge Hallyn
Cc: "Eric W. Biederman"
Cc: Pavel Emelyanov
Cc: Al Viro
Cc: KOSAKI Motohiro
Cc: Michael Kerrisk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
