has been set. Assert that this is the case so that we catch filesystems
who are using naked VOP_LOCKs in illegal cases.
Sponsored by: Isilon Systems, Inc.
considered to be as good as an exclusive lock, although there is still a
possibility of someone acquiring a VOP LOCK while xlock is held.
Sponsored by: Isilon Systems, Inc.
List devfs_dirents rather than vnodes off their shared struct cdev, this
saves a pointer field in the vnode at the expense of a field in the
devfs_dirent. There are often 100 times more vnodes so this is bargain.
In addition it makes it harder for people to try to do stypid things like
"finding the vnode from cdev".
Since DEVFS handles all VCHR nodes now, we can do the vnode related
cleanup in devfs_reclaim() instead of in dev_rel() and vgonel().
Similarly, we can do the struct cdev related cleanup in dev_rel()
instead of devfs_reclaim().
rename idestroy_dev() to destroy_devl() for consistency.
Add LIST_ENTRY de_alias to struct devfs_dirent.
Remove v_specnext from struct vnode.
Change si_hlist to si_alist in struct cdev.
String new devfs vnodes' devfs_dirent on si_alist when
we create them and take them off in devfs_reclaim().
Fix devfs_revoke() accordingly. Also don't clear fields
devfs_reclaim() will clear when called from vgone();
Let devfs_reclaim() call dev_rel() instead of vgonel().
Move the usecount tracking from dev_rel() to devfs_reclaim(),
and let dev_rel() take a struct cdev argument instead of vnode.
Destroy SI_CHEAPCLONE devices in dev_rel() (instead of
devfs_reclaim()) when they are no longer used. (This
should maybe happen in devfs_close() instead.)
a socket from a regular socket to a listening socket able to accept new
connections. As part of this state transition, solisten() calls into the
protocol to update protocol-layer state. There were several bugs in this
implementation that could result in a race wherein a TCP SYN received
in the interval between the protocol state transition and the shortly
following socket layer transition would result in a panic in the TCP code,
as the socket would be in the TCPS_LISTEN state, but the socket would not
have the SO_ACCEPTCONN flag set.
This change does the following:
- Pushes the socket state transition from the socket layer solisten() to
to socket "library" routines called from the protocol. This permits
the socket routines to be called while holding the protocol mutexes,
preventing a race exposing the incomplete socket state transition to TCP
after the TCP state transition has completed. The check for a socket
layer state transition is performed by solisten_proto_check(), and the
actual transition is performed by solisten_proto().
- Holds the socket lock for the duration of the socket state test and set,
and over the protocol layer state transition, which is now possible as
the socket lock is acquired by the protocol layer, rather than vice
versa. This prevents additional state related races in the socket
layer.
This permits the dual transition of socket layer and protocol layer state
to occur while holding locks for both layers, making the two changes
atomic with respect to one another. Similar changes are likely require
elsewhere in the socket/protocol code.
Reported by: Peter Holm <peter@holm.cc>
Review and fixes from: emax, Antoine Brodin <antoine.brodin@laposte.net>
Philosophical head nod: gnn
only call the protocol's pru_rcvd() if the protocol has the flag
PR_WANTRCVD set. This brings that instance of pru_rcvd() into line with
the rest, which do check the flag.
MFC after: 3 days
of the global UNIX domain socket mutex: no protection is needed that
early in the setup of the UNIX domain socket and socket structures.
MFC after: 3 days
patch from kan@).
Pull bufobj_invalbuf() out of vinvalbuf() and make g_vfs call it on
close. This is not yet a generally safe function, but for this very
specific use it is safe. This solves the problem with buffers not
being flushed by unmount or after failed mount attempts.
so->so_options when solisten() will succeed, rather than setting it
conditionally based on there not being queued sockets in the completed
socket queue. Otherwise, if the protocol exposes new sockets via the
completed queue before solisten() completes, the listen() system call
will succeed, but the socket and protocol state will be out of sync.
For TCP, this didn't happen in practice, as the TCP code will panic if
a new connection comes in after the tcpcb has been transitioned to a
listening state but the socket doesn't have SO_ACCEPTCONN set.
This is historical behavior resulting from bitrot since 4.3BSD, in which
that line of code was associated with the conditional NULL'ing of the
connection queue pointers (one-time initialization to be performed
during the transition to a listening socket), which are now initialized
separately.
Discussed with: fenner, gnn
MFC after: 3 days
driver. This used to be handled by cpufreq_drv_settings() but it's
useful to get the type/flags separately from getting the settings.
(For example, you don't have to pass an array of cf_setting just to find
the driver type.)
Use this new method in our in-tree drivers to detect reliably if acpi_perf
is present and owns the hardware. This simplifies logic in drivers as well
as fixing a bug introduced in my last commit where too many drivers attached.
soref() to also covering the update of so_state. While no other user
threads can update the socket state here as it's not yet hooked up to
the file descriptor array yet, the protocol could also frob the
socket state here, leading to a lost update to the so_state field.
No reported instances of this bug (as yet).
MFC after: 3 days
connection status before inserting the new socket into the listen
socket's accept queue, or there might be a race in which another thread
wakes up when the accept lock is released, and sees the socket before its
state is set correctly. The wakeup still occurs after the accept lock is
released. There have been no diagnoses of this bug in real-world systems
(as yet).
MFC after: 3 days
statement from some files, so re-add it for the moment, until the
related legalese is sorted out. This change affects:
sys/kern/kern_mbuf.c
sys/vm/memguard.c
sys/vm/memguard.h
sys/vm/uma.h
sys/vm/uma_core.c
sys/vm/uma_dbg.c
sys/vm/uma_dbg.h
sys/vm/uma_int.h
the rate for the 100% state once. Afterwards, use that value for deriving
states. This should fix the problem where the calibrated frequency was
different once a switch was done, giving a different set of levels each
time. Also, properly search for the right cpufreqX device when detaching.
override the current freq level temporarily and restore it when the
higher priority condition is past. Note that only the first overridden
value is saved. Callers pass NULL to CPUFREQ_SET to restore the saved
level. Priorities are not yet used so this commit should have no effect.
are not added to the list(s) of available settings. However, other drivers
can call the CPUFREQ_DRV_SETTINGS() method on those devices directly to
get info about available settings.
Update the acpi_perf(4) driver to use this flag in the presence of
"functional fixed hardware." Thus, future drivers like Powernow can
query acpi_perf for platform info but perform frequency transitions
themselves.
on dev.cpu.0 will affect all of the CPUs together. In the future,
independent control will be supported but this is good enough for now.
Check that the timecounter isn't TSC before switching (from Colin Percival.)
former is callable from user space and the latter from the kernel one. Make
kernel version take additional argument which tells if the respective call
should check for additional restrictions for sending signals to suid/sugid
applications or not.
Make all emulation layers using non-checked version, since signal numbers in
emulation layers can have different meaning that in native mode and such
protection can cause misbehaviour.
As a result remove LIBTHR from the signals allowed to be delivered to a
suid/sugid application.
Requested (sorta) by: rwatson
MFC after: 2 weeks
This information will be very useful for people who are tuning applications
which have a dependence on IPC mechanisms.
The following OIDs were documented:
Message queues:
kern.ipc.msgmax
kern.ipc.msgmni
kern.ipc.msgmnb
kern.ipc.msgtlq
kern.ipc.msgssz
kern.ipc.msgseg
Semaphores:
kern.ipc.semmap
kern.ipc.semmni
kern.ipc.semmns
kern.ipc.semmnu
kern.ipc.semmsl
kern.ipc.semopm
kern.ipc.semume
kern.ipc.semusz
kern.ipc.semvmx
kern.ipc.semaem
Shared memory:
kern.ipc.shmmax
kern.ipc.shmmin
kern.ipc.shmmni
kern.ipc.shmseg
kern.ipc.shmall
kern.ipc.shm_use_phys
kern.ipc.shm_allow_removed
kern.ipc.shmsegs
These new descriptions can be viewed using sysctl -d
PR: kern/65219
Submitted by: Dan Nelson <dnelson at allantgroup dot com> (modified)
No objections: developers@
Descriptions reviewed by: gnn
MFC after: 1 week
suid application. The problem is that Linux applications using old Linux
threads (pre-NPTL) use signal 32 (linux SIGRTMIN) for communication between
thread-processes. If such an linux application is installed suid or sgid
and security.bsd.conservative_signals=1 (default), then permission will be
denied to send such a signal and the application will freeze.
I believe the same will be true for native applications that use libthr,
since libthr uses SIGTHR for implementing conditional variables.
PR: 72922
Submitted by: Andriy Gapon <avg@icyb.net.ua>
MFC after: 2 weeks
list, set `curr_callout' to NULL. This ensures that we won't attempt
to cancel the current callout if the original callout structure
gets recycled while we wait to acquire Giant.
This is reported to fix an intermittent syscons problem that was
introduced by revision 1.96.
do not need to perform an extra memory fetch in the Packet (Mbuf+Cluster)
constructor to initialize the reference counter anymore. The reference
counts are located in a separate memory region (in the slab header,
because this zone is UMA_ZONE_REFCNT), so the memory fetch resulted very
often in a cache miss. Additionally, and perhaps more significantly,
optimize the free mbuf+cluster (packet) case, which is very common, to
no longer require an atomic operation on free (to verify the reference
counter) if the reference on the cluster has never been increased (also
very common). Reduces an atomic on mbuf free on average.
Original patch submitted by: Gerrit Nagelhout <gnagelhout@sandvine.com>
behaviour of chflags within a jail. If set to 0 (the default), then a
jailed root user is treated as an unprivileged user; if set to 1, then
a jailed root user is treated the same as an unjailed root user.
This is necessary to allow "make installworld" to work inside a jail,
since it attempts to manipulate the system immutable flag on certain
files.
Discussed with: csjp, rwatson
MFC after: 2 weeks
Give FFS vnodes a specific bufwrite method which contains all the
background write stuff and then calls into the default bufwrite()
for the rest of the job.
Remove all the background write related stuff from the normal bufwrite.
This drags the softdep_move_dependencies() back into FFS.
Long term, it is worth looking at simply copying the data into
allocated memory and issuing the bio directly and not create the
"shadow buf" in the first place (just like copy-on-write is done
in snapshots for instance). I don't think we really gain anything
but complexity from doing this with a buf.
structure in the struct pointed to by the 3rd argument for IPC_STAT and
get rid of the 4th argument. The old way returned a pointer into the
kernel array that the calling function would then access afterwards
without holding the appropriate locks and doing non-lock-safe things like
copyout() with the data anyways. This change removes that unsafeness and
resulting race conditions as well as simplifying the interface.
- Implement kern_foo wrappers for stat(), lstat(), fstat(), statfs(),
fstatfs(), and fhstatfs(). Use these wrappers to cut out a lot of
code duplication for freebsd4 and netbsd compatability system calls.
- Add a new lookup function kern_alternate_path() that looks up a filename
under an alternate prefix and determines which filename should be used.
This is basically a more general version of linux_emul_convpath() that
can be shared by all the ABIs thus allowing for further reduction of
code duplication.
callout is first initialised, using a new function callout_init_mtx().
The callout system will acquire this mutex before calling the callout
function and release it on return.
In addition, the callout system uses the mutex to avoid most of the
complications and race conditions inherent in asynchronous timer
facilities, so mutex-protected callouts have much simpler semantics.
As long as the mutex is held when invoking callout_stop() or
callout_reset(), then these functions will guarantee that the callout
will be stopped, even if softclock() had already begun to process
the callout.
Existing Giant-locked callouts will automatically pick up the new
race-free semantics. This should close a number of race conditions
in the USB code and probably other areas of the kernel too.
There should be no change in behaviour for "MP-safe" callouts; these
still need to use the techniques mentioned in timeout(9) to avoid
race conditions.
frequency as a percentage of the base rate and do not change the base
rate directly. The cpufreq framework combines these with absolute drivers
to produce synthesized levels made of one or more settings.
select the CPU frequency level (say for cooling). The driver interface
allows hardware drivers to announce themselves as capable of adjusting
an individual frequency setting.
- Add buffer size limitations (overflow will not be possible anymore).
- Add 'visible' option, which will allow for passphrase reading in the
future.
- Remove special treatment of '@' and '#', those two are only confusing.
Discussed with: rwatson
MFC after: 2 weeks
tond and not fromnd. This could lead us to leak Giant, or unlock it
twice, depending on the filesystems involved. renames within a single
filesystem would not have caused any problems.
Sponsored by: Isilon Systems, Inc.
all reserved, as the lisence makes clear), and strike the third clause
(now this is a 2-clause liberal BSDL as are the rest of files I hold
copyright over).
copies arguments into the kernel space and one that operates
completely in the kernel space;
o use kernel-only version of execve(2) to kill another stackgap in
linuxlator/i386.
Obtained from: DragonFlyBSD (partially)
MFC after: 2 weeks
Add minor2unit() in addition to dev2unit() and unit2minor().
If it wasn't such a hazzle we should redefine minor numbers in
the kernel without the gap for the major number, but it's not worth
the bother (yet).
a process return to userspace if it had pending GEOM events.
We need to have the same check in the exit pass to catch the case
where a GEOM related filedescriptor is not explicitly closed by
the process.
Bumped into by: people using dd(1) to build releases, nanobsd etc.
from the userland and pushes results back and the second which does
actual processing. Use the latter to eliminate stackgap in the linux wrapper
of that syscall.
MFC after: 2 weeks
pops data from the userland and pushes results back and the second which does
actual processing. Use the latter to eliminate stackgap in the linux wrappers
of those syscalls.
MFC after: 2 weeks
missed that when the vnode bypass was introduced.
Deal with zero length transfers before we even get to fo_ops->fo_read().
Found by: Slawa Olhovchenkov <slwzxy.spb.ru@zxy.spb.ru>
PR: 75758
the name Sande^H^H^H^H^Hvnode_create_vobject().
Make the new function take a size argument which removes the need for
a VOP_STAT() or a very pessimistic guess for disks.
Call that new function from vop_stdcreatevobject().
Make vnode_pager_alloc() private now that its only user came home.
short to unsigned short.
- Add SYSCTL_PROC() around somaxconn, not accepting values < 1 or > U_SHRTMAX.
Before this change setting somaxconn to smth above 32767 and calling
listen(fd, -1) lead to a socket, which doesn't accept connections at all.
Reviewed by: rwatson
Reported by: Igor Sysoev
- Remove some KASSERTs which are invalid if the appropriate lock is
not held.
- Slightly restructure bremfree() so that it is more sane.
- Change the flush code in bdwrite() to avoid acquiring a mutex
whenever possible.
- Change the flush code in bdwrite() to avoid holding the bufobj mutex
while calling buf_countdeps(). This introduces a lock-order
relationship with the softdep lock that can not otherwise be resolved.
- Don't set B_DONE until bufdone() is complete, otherwise another
processor may believe the buf is done before it is.
- Only acquire Giant if the caller has set b_iodone. Don't grab giant
around normal bufdone() calls.
Sponsored By: Isilon Systems, Inc.
to off.
- Protect access to mnt_kern_flag with the mointpoint mutex.
- Remove some KASSERTs which are not legal checks without the appropriate
locks held.
- Use VCANRECYCLE() rather than rolling several slightly different
checks together.
- Return from vtryrecycle() with a recycled vnode rather than a locked
vnode. This simplifies some locking.
- Remove several GIANT_REQUIRED lines.
- Add a few KASSERTs to help with INACT debugging.
Sponsored By: Isilon Systems, Inc.
- Protect access to mnt_kern_flag with the mountpoint mutex.
- Use the appropriate nd flags to deal with giant in vn_open_cred().
We currently determine whether the caller is mpsafe by checking
for a valid fdidx. Any caller coming from user-space is now
mpsafe and supplies a valid fd. No kenrel callers have been
converted to mpsafe, so this check is sufficient for now.
- Use VFS_LOCK_GIANT instead of manual giant acquisition where
appropriate.
Sponsored By: Isilon Systems, Inc.
require it.
- Track the status of Giant with the nd flag HASGIANT.
- Release giant on return of namei() callers are not marked MPSAFE as
they already own giant.
Sponsored By: Isilon Systems, Inc.
vnode lock is much simpler than I originally thought it would be.
Now, the cache lock is always acquired before the vnode lock.
- Provide some gotos in __getcwd() to simplify the unlocking a bit.
- Move Giant acquisition down into __getcwd().
Sponsored By: Isilon Systems, Inc.
if the lockmgr interlock is dropped after the caller's interlock
is dropped.
- Change some lockmgr KTRs to be slightly more helpful.
Sponsored By: Isilon Systems, Inc.
witness_proc_has_locks(), as they are unused, which results in a compiler
error. This problem was introduced with the implementation of "show
alllocks".
Spotted by: Artem Kuchin <matrix at itlegion dot ru>
designed to help detect tamper-after-free scenarios, a problem more
and more common and likely with multithreaded kernels where race
conditions are more prevalent.
Currently MemGuard can only take over malloc()/realloc()/free() for
particular (a) malloc type(s) and the code brought in with this
change manually instruments it to take over M_SUBPROC allocations
as an example. If you are planning to use it, for now you must:
1) Put "options DEBUG_MEMGUARD" in your kernel config.
2) Edit src/sys/kern/kern_malloc.c manually, look for
"XXX CHANGEME" and replace the M_SUBPROC comparison with
the appropriate malloc type (this might require additional
but small/simple code modification if, say, the malloc type
is declared out of scope).
3) Build and install your kernel. Tune vm.memguard_divisor
boot-time tunable which is used to scale how much of kmem_map
you want to allott for MemGuard's use. The default is 10,
so kmem_size/10.
ToDo:
1) Bring in a memguard(9) man page.
2) Better instrumentation (e.g., boot-time) of MemGuard taking
over malloc types.
3) Teach UMA about MemGuard to allow MemGuard to override zone
allocations too.
4) Improve MemGuard if necessary.
This work is partly based on some old patches from Ian Dowse.
