ref while we're calling vgone(). This prevents transient refs from
re-adding us to the free list. Previously, a vfree() triggered via
vinvalbuf() getting rid of all of a vnode's pages could place a partially
destructed vnode on the free list where vtryrecycle() could find it. The
first call to vtryrecycle would hang up on the vnode lock, but when it
failed it would place a now dead vnode onto the free list, and another
call to vtryrecycle() would free an already free vnode. There were many
complications of having a zero ref count while freeing which can now go
away.
- Change vdropl() to release the interlock before returning. All callers
now respect this, so vdropl() directly frees VI_DOOMED vnodes once the
last ref is dropped. This means that we'll never have VI_DOOMED vnodes
on the free list.
- Seperate v_incr_usecount() into v_incr_usecount(), v_decr_usecount() and
v_decr_useonly(). The incr/decr split is so that incr usecount can
return with the interlock still held while decr drops the interlock so
it can call vdropl() which will potentially free the vnode. The calling
function can't drop the lock of an already free'd node. v_decr_useonly()
drops a usecount without droping the hold count. This is done so the
usecount reaches zero in vput() before we recycle, however the holdcount
is still 1 which prevents any new references from placing the vnode
back on the free list.
- Fix vnlrureclaim() to vhold the vnode since it doesn't do a vget(). We
wouldn't want vnlrureclaim() to bump the usecount since this has
different semantics. Also change vnlrureclaim() to do a NOWAIT on the
vn_lock. When this function runs we're usually in a desperate situation
and we wouldn't want to wait for any specific vnode to be released.
- Fix a bunch of misc comments to reflect the new behavior.
- Add vhold() and vdrop() to vflush() for the same reasons that we do in
vlrureclaim(). Previously we held no reference and a vnode could have
been freed while we were waiting on the lock.
- Get rid of vlruvp() and vfreehead(). Neither are used. vlruvp() should
really be rethought before it's reintroduced.
- vgonel() always returns with the vnode locked now and never puts the
vnode back on a free list. The vnode will be freed as soon as the last
reference is released.
Sponsored by: Isilon Systems, Inc.
Debugging help from: Kris Kennaway, Peter Holm
Approved by: re (blanket vfs)
of the clean and dirty lists. This is in an attempt to catch the wrong
bufobj problem sooner.
- In vgonel() don't acquire an extra reference in the active case, the
vnode lock and VI_DOOMED protect us from recursively cleaning.
- Also in vgonel() clean up some stale comments.
Sponsored by: Isilon Systems, Inc.
Approved by: re (blanket vfs)
used to ensure that we weren't exiting the syscall with a lock still
held. This wasn't safe, however, because we'd already executed a vput()
and on a loaded system the vnode may have been free'd by the time we
assert. This functionality is also handled by the td_locks assert in
userret, which doesn't tell you what the syscall was, but will at least
panic before you deadlock.
Sponsored by: Isilon Systems, Inc.
Discovred by: Peter Holm
Approved by: re (blanket vfs)
anyway and it's not used outside of vfs_subr.c.
- Change vgonel() to accept a parameter which determines whether or not
we'll put the vnode on the free list when we're done.
- Use the new vgonel() parameter rather than VI_DOOMED to signal our
intentions in vtryrecycle().
- In vgonel() return if VI_DOOMED is already set, this vnode has already
been reclaimed.
Sponsored by: Isilon Systems, Inc.
most of the code to deal with them has been dead for sometime. Simplify
the code by doing an insert sort hinted by the current head position.
Met with apathy by: arch@
I introduce a very small race here (some file system can be mounted or
unmounted between 'count' calculation and file systems list creation),
but it is harmless.
Found by: FreeBSD Kernel Stress Test Suite: http://www.holm.cc/stress/
Reported by: Peter Holm <peter@holm.cc>
It can be used to panic the kernel by giving too big value.
Fix it by moving allocation and size verification into kern_getfsstat().
This even simplifies kern_getfsstat() consumers, but destroys symmetry -
memory is allocated inside kern_getfsstat(), but has to be freed by the
caller.
Found by: FreeBSD Kernel Stress Test Suite: http://www.holm.cc/stress/
Reported by: Peter Holm <peter@holm.cc>
o getsockopt(SO_ACCEPTFILTER) always returns success on listen socket
even we didn't install accept filter on the socket.
o Fix these bugs and add regression tests for them.
Submitted by: Igor Sysoev [1]
Reviewed by: alfred
MFC after: 2 weeks
events could be added to cover other interesting details.
- Add some VNASSERTs to discover places where we access vnodes after
they have been uma_zfree'd before we try to free them again.
- Add a few more VNASSERTs to vdestroy() to be certain that the vnode is
really unused.
Sponsored by: Isilon Systems, Inc.
atomic write request, it can fill the buffer cache with the entirety
of that write in order to handle retries. However, it never drops
the vnode lock, or else it wouldn't be atomic, so it ends up waiting
indefinitely for more buf memory that cannot be gotten as it has it
all, and it waits in an uncancellable state.
To fix this, hibufspace is exported and scaled to a reasonable
fraction. This is used as the limit of how much of an atomic write
request by the NFS client will be handled asynchronously. If the
request is larger than this, it will be turned into a synchronous
request which won't deadlock the system. It's possible this value is
far off from what is required by some, so it shall be tunable as soon
as mount_nfs(8) learns of the new field.
The slowdown between an asynchronous and a synchronous write on NFS
appears to be on the order of 2x-4x.
General nod by: gad
MFC after: 2 weeks
More testing: wes
PR: kern/79208
well worth the bloat.
- Change the formatting of 'show ktr' slightly to accommodate the
additional field. Remove a tab from the verbose output and place the
actual trace data after a : so it is more easy to understand which
part is the event and which is part of the record.
struct ifnet or the layer 2 common structure it was embedded in have
been replaced with a struct ifnet pointer to be filled by a call to the
new function, if_alloc(). The layer 2 common structure is also allocated
via if_alloc() based on the interface type. It is hung off the new
struct ifnet member, if_l2com.
This change removes the size of these structures from the kernel ABI and
will allow us to better manage them as interfaces come and go.
Other changes of note:
- Struct arpcom is no longer referenced in normal interface code.
Instead the Ethernet address is accessed via the IFP2ENADDR() macro.
To enforce this ac_enaddr has been renamed to _ac_enaddr.
- The second argument to ether_ifattach is now always the mac address
from driver private storage rather than sometimes being ac_enaddr.
Reviewed by: sobomax, sam
UFS by:
- Making the pre and post hooks for the VOP functions work even when
DEBUG_VFS_LOCKS is not defined.
- Moving the KNOTE activations into the corresponding VOP hooks.
- Creating a MNTK_NOKNOTE flag for the mnt_kern_flag field of struct
mount that permits filesystems to disable the new behavior.
- Creating a default VOP_KQFILTER function: vfs_kqfilter()
My benchmarks have not revealed any performance degradation.
Reviewed by: jeff, bde
Approved by: rwatson, jmg (kqueue changes), grehan (mentor)
- Implement sampling modes and logging support in hwpmc(4).
- Separate MI and MD parts of hwpmc(4) and allow sharing of
PMC implementations across different architectures.
Add support for P4 (EMT64) style PMCs to the amd64 code.
- New pmcstat(8) options: -E (exit time counts) -W (counts
every context switch), -R (print log file).
- pmc(3) API changes, improve our ability to keep ABI compatibility
in the future. Add more 'alias' names for commonly used events.
- bug fixes & documentation.
and extend its functionality:
value policy
0 show all mount-points without any restrictions
1 show only mount-points below jail's chroot and show only part of the
mount-point's path (if jail's chroot directory is /jails/foo and
mount-point is /jails/foo/usr/home only /usr/home will be shown)
2 show only mount-point where jail's chroot directory is placed.
Default value is 2.
Discussed with: rwatson
security.bsd.see_other_uids is set to 0, etc.
One can check if invisible process is active, by doing:
# ktrace -p <pid>
If ktrace returns 'Operation not permitted' the process is alive and
if returns 'No such process' there is no such process.
MFC after: 1 week
milliseconds due to what is essentially n^2 algorithmic complexity. This
change makes the algorithm N*2 instead. This heavy processing manifested
itself as skipping in audio and video playback due to the long scheduling
latencies and contention on giant by pcm.
- flushbufqueues() is now responsible for flushing multiple buffers
rather than one at a time. This allows us to save our progress in the
list by using a sentinal. We must do the numdirtywakeup() and
waitrunningbufspace() here now rather than in buf_daemon().
- Also add a uio_yield() after we have processed the list once for bufs
without deps and again for bufs with deps. This is to release Giant
and allow any other giant locked code to proceed.
Tested by: Many users on current@
Revealed by: schedgraph traces sent by Emil Mikulic & Anthony Ginepro
list on fork() if the process doesn't actually have references to any
semaphores. This avoids extra work, as well as potentially asking to
allocate storage for 0 references.
Found by: avatar
MFC after: 1 week
points to convert _sema() to _sem() for consistency purposes with
respect to the other semaphore-related entry points:
mac_init_sysv_sema() -> mac_init_sysv_sem()
mac_destroy_sysv_sem() -> mac_destroy_sysv_sem()
mac_create_sysv_sema() -> mac_create_sysv_sem()
mac_cleanup_sysv_sema() -> mac_cleanup_sysv_sem()
Congruent changes are made to the policy interface to support this.
Obtained from: TrustedBSD Project
Sponsored by: SPAWAR, SPARTA
as this happens via thread_switchout(). I don't particularly like the
structure of the code here. We twice call out to thread code when
a thread is voluntarily switching. Once to thread_switchout() and once
to slot_fill(), while sched_4BSD does even more work which is redundant
to select another thread to use our remaining slice. This should be
simplified in the future, but for now I'm only going to fix the bug not
the bad design.
mutex instead of a MTX_DEF one in order to defer preemption while
reading the date and time registers. If we don't manage to read them
within the time slot where we are guaranteed that no updates occur we
might actually read them during an update in which case the output is
undefined.
aio_write(2) completion through kevent(2). This method does not work on
64-bit architectures. It was deprecated in FreeBSD 4.4. See revisions
1.87 and 1.70.2.7.
Change aio_physwakeup() to call psignal(9) directly rather than indirectly
through a timeout(9). Discussed with: bde
Correct a bug introduced in revision 1.65 that could result in premature
delivery of a signal if an lio_listio(2) consisted of a mixture of
direct/raw and queued I/O operations. Observed by: tegge
Eliminate a field from struct kaioinfo that is now unused.
Reviewed by: tegge
slot for us. Previously, we would take two slots on every preempt, and
setrunqueue() would fix it up for us in the non threaded case. The
threaded case was simply broken.
- Clean up flags, prototypes, comments.
file's access time should be updated when it gets executed. A while
ago the mechanism used to exec was changed to use a more mmap based
mechanism and this behavior was broken as a side-effect of that.
A new vnode flag is added that gets set when the file gets executed,
and the VOP_SETATTR() vnode operation gets called. The underlying
filesystem is expected to handle it based on its own semantics, some
filesystems don't support access time at all. Those that do should
handle it in a way that does not block, does not generate I/O if possible,
etc. In particular vn_start_write() has not been called. The UFS code
handles it the same way as it would normally handle the access time if
a file was read - the IN_ACCESS flag gets set in the inode but no other
action happens at this point. The actual time update will happen later
during a sync (which handles all the necessary locking).
Got me into this: cperciva
Discussed with: a lot with bde, a little with kan
Showed patches to: phk, jeffr, standards@, arch@
Minor discussion on: arch@
audit event identifier associated with each system call, which will
be stored by makesyscalls.sh in the sy_auevent field of struct sysent.
For now, default the audit identifier on all system calls to AUE_NULL,
but in the near future, other BSM event identifiers will be used. The
mapping of system calls to event identifiers is many:one due to
multiple system calls that map to the same end functionality across
compatibility wrappers, ABI wrappers, etc.
Submitted by: wsalamon
Obtained from: TrustedBSD Project
allocators: a set of power-of-two UMA zones for small allocations, and the
VM page allocator for large allocations. In order to maintain unified
statistics for specific malloc types, kernel malloc maintains a separate
per-type statistics pool, which can be monitored using vmstat -m. Prior
to this commit, each pool of per-type statistics was protected using a
per-type mutex associated with the malloc type.
This change modifies kernel malloc to maintain per-CPU statistics pools
for each malloc type, and protects writing those statistics using critical
sections. It also moves to unsynchronized reads of per-CPU statistics
when generating coalesced statistics. To do this, several changes are
implemented:
- In the previous world order, the statistics memory was allocated by
the owner of the malloc type structure, allocated statically using
MALLOC_DEFINE(). This embedded the definition of the malloc_type
structure into all kernel modules. Move to a model in which a pointer
within struct malloc_type points at a UMA-allocated
malloc_type_internal data structure owned and maintained by
kern_malloc.c, and not part of the exported ABI/API to the rest of
the kernel. For the purposes of easing a possible MFC, re-use an
existing pointer in 'struct malloc_type', and maintain the current
malloc_type structure size, as well as layout with respect to the
fields reused outside of the malloc subsystem (such as ks_shortdesc).
There are several unused fields as a result of no longer requiring
the mutex in malloc_type.
- Struct malloc_type_internal contains an array of malloc_type_stats,
of size MAXCPU. The structure defined above avoids hard-coding a
kernel compile-time value of MAXCPU into kernel modules that interact
with malloc.
- When accessing per-cpu statistics for a malloc type, surround read -
modify - update requests with critical_enter()/critical_exit() in
order to avoid races during write. The per-CPU fields are written
only from the CPU that owns them.
- Per-CPU stats now maintained "allocated" and "freed" counters for
number of allocations/frees and bytes allocated/freed, since there is
no longer a coherent global notion of the totals. When coalescing
malloc stats, accept a slight race between reading stats across CPUs,
and avoid showing the user a negative allocation count for the type
in the event of a race. The global high watermark is no longer
maintained for a malloc type, as there is no global notion of the
number of allocations.
- While tearing up the sysctl() path, also switch to using sbufs. The
current "export as text" sysctl format is retained with the same
syntax. We may want to change this in the future to export more
per-CPU information, such as how allocations and frees are balanced
across CPUs.
This change results in a substantial speedup of kernel malloc and free
paths on SMP, as critical sections (where usable) out-perform mutexes
due to avoiding atomic/bus-locked operations. There is also a minor
improvement on UP due to the slightly lower cost of critical sections
there. The cost of the change to this approach is the loss of a
continuous notion of total allocations that can be exploited to track
per-type high watermarks, as well as increased complexity when
monitoring statistics.
Due to carefully avoiding changing the ABI, as well as hardening the ABI
against future changes, it is not necessary to recompile kernel modules
for this change. However, MFC'ing this change to RELENG_5 will require
also MFC'ing optimizations for soft critical sections, which may modify
exposed kernel ABIs. The internal malloc API is changed, and
modifications to vmstat in order to restore "vmstat -m" on core dumps will
follow shortly.
Several improvements from: bde
Statistics approach discussed with: ups
Tested by: scottl, others
Only panic is fixed, module will be still listed in kldstat(8) output.
Not sure what is correct fix, because adding unloading code in case of
failure to linker_init_kernel_modules() doesn't work.
of having the kernel parse that line and add an entry to the argument list for
each 'separate word' it finds, have it add only one entry which holds all
the words found on that line. The old behavior is useful in some situations,
but it does not match the way any other operating system will parse that line.
This has been discussed in the thread "Bug in #! processing - One More Time"
on the freebsd-arch mailing list (starting back on Feb 24, 2005). The first
few messages in that thread provide the background in much detail.
PR: 16393
Reviewed by: freebsd-arch
sysctl path. While this code is close to MPSAFE, it may require some
additional locking. Mark ntp_gettime1() as GIANT_REQUIRED for now.
Suggested by: phk
on the their simply wrapping MPSAFE implementations of existing MPSAFE
system calls:
getfsstat()
lseek()
stat()
lstat()
truncate()
ftruncate()
statfs()
fstatfs()
Note that ogetdirentries() is not marked MPSAFE because it does not share
the MPSAFE implementation used for getdirentries(), and requires separate
locking to be implemented.
that protects socket and receive socket buffer state, and a second
mutex to protect send socket buffer state. In some places, the
mutex shared between the socket and receive socket buffer will be
acquired twice, once by each layer, resulting in some
inconsistency, but providing the abstraction benefit of being able
to more easily separate the two mutexes in the future if desired.
When transitioning a socket to the SS_ISDISCONNECTING or
SS_ISDISCONNECTED states, grab the socket/receive socket buffer lock
once rather than grabbing it as the socket lock, modifying socket
state, then grabbing a second time as the receive lock in order to
modify the socket buffer state to indicate no further data can be
read. This change is believed to close a race between the change in
socket state and the change in socket buffer state, which for a
remotely initiated close on a UNIX domain socket, resulted in
soreceive() returning ENOTCONN rather than an EOF condition.
A similar race still exists in the case of send, however, and is
harder to fix as the socket and send socket buffer mutexes are not
the same, and we would like to avoid holding combinations of socket
mutexes over sb_upcall until we've finished clarifying the locking
protocol for upcalls.
This change has the side affect of reducing the number of mutex
operations to initiate disconnect or perform disconnect on a
socket by two.
PR: 78824
Rerported by: Marc Olzheim <marcolz@stack.nl>
MFC after: 2 weeks
so do not duplicate the code in cvtstatfs().
Note, that we now need to clear fsid in freebsd4_getfsstat().
This moves all security related checks from functions like cvtstatfs()
and will allow to add more security related stuff (like statfs(2), etc.
protection for jails) a bit easier.
1. Copy a NULL-terminated string into a fixed-length buffer, and
2. copyout that buffer to userland,
we really ought to
0. Zero the entire buffer
first.
Security: FreeBSD-SA-05:08.kmem
to the mbuf. Offset cannot exceed MHLEN bytes. This is currently used to
fix Ethernet header alignment problem on alpha and sparc64. Also change all
users of m_uiotombuf to pass proper offset.
Reviewed by: jmg, sam
Tested by: Sten Spans "sten AT blinkenlights DOT nl"
MFC after: 1 week
access to POSIX Semaphores:
mac_init_posix_sem() Initialize label for POSIX semaphore
mac_create_posix_sem() Create POSIX semaphore
mac_destroy_posix_sem() Destroy POSIX semaphore
mac_check_posix_sem_destroy() Check whether semaphore may be destroyed
mac_check_posix_sem_getvalue() Check whether semaphore may be queried
mac_check_possix_sem_open() Check whether semaphore may be opened
mac_check_posix_sem_post() Check whether semaphore may be posted to
mac_check_posix_sem_unlink() Check whether semaphore may be unlinked
mac_check_posix_sem_wait() Check whether may wait on semaphore
Update Biba, MLS, Stub, and Test policies to implement these entry points.
For information flow policies, most semaphore operations are effectively
read/write.
Submitted by: Dandekar Hrishikesh <rishi_dandekar at sbcglobal dot net>
Sponsored by: DARPA, McAfee, SPARTA
Obtained from: TrustedBSD Project
to ksem.h so that they are accessible from the MAC Framework for the
purposes of labeling and enforcing additional protections. #error
if these are included without _KERNEL, since they are not intended
(nor installed) for user application use.
Submitted by: Dandekar Hrishikesh <rishi_dandekar at sbcglobal dot net>
Sponsored by: DARPA, SPARTA
Obtained from: TrustedBSD Project
devstat_end_transaction is called from a fast interrupt. Presently
there is no way for mtx_assert to determine that we're not executing
in a real thread context.
Submitted by: jhusted@isilon.com
drop the check+initialization for a straight initialization. Also
assert that curthread will never be NULL just to be sure.
Discussed with: rwatson, peter
MFC after: 1 week
are set when we attempt to remove a buffer from a queue we should panic.
Hopefully this will catch the source of the wrong bufobj panics.
Sponsored by: Isilon Systems, Inc.
a new entry in the taskqueue struct each time it wakes up to see if it
should terminate
o adjust TASKQUEUE_DEFINE_THREAD & co. to record the thread/proc identity for
the shutdown rendezvous
o replace wakeup after adding a task to a queue with wakeup_one; this helps
queues where multiple threads are used to service tasks (e.g. acpi)
o remove NULL check of tq_enqueue method; it should never be NULL
Reviewed by: dfr, njl
a regular IPI vector, but this vector is blocked when interrupts are disabled.
With "options KDB_STOP_NMI" and debug.kdb.stop_cpus_with_nmi set, KDB will
send an NMI to each CPU instead. The code also has a context-stuffing
feature which helps ddb extract the state of processes running on the
stopped CPUs.
KDB_STOP_NMI is only useful with SMP and complains if SMP is not defined.
This feature only applies to i386 and amd64 at the moment, but could be
used on other architectures with the appropriate MD bits.
Submitted by: ups
vtryrecycle(). We could sometimes get into situations where two threads
could try to recycle the same vnode before this.
- vtryrecycle() is now responsible for returning the vnode to the free list
if it fails and someone else hasn't done it.
- Make a new function vfreehead() which moves a vnode to the head of the
free list and use it in vgone() to clean up that code a bit.
Sponsored by: Isilon Systems, Inc.
Reported by: pho, kkenn
modify-after-free races when the task structure is malloc'd
o shrink task structure by removing ta_flags (no longer needed with
avoid fix) and combining ta_pending and ta_priority
Reviewed by: dwhite, dfr
MFC after: 4 days
inherit signal mask from parent thread, setup TLS and stack, and
user entry address.
Also support POSIX thread's PTHREAD_SCOPE_PROCESS and PTHREAD_SCOPE_SYSTEM,
sysctl is also provided to control the scheduler scope.
in other codes. Add cpu_set_user_tls, use it to tweak user register
and setup user TLS. I ever wanted to merge it into cpu_set_kse_upcall,
but since cpu_set_kse_upcall is also used by M:N threads which may
not need this feature, so I wrote a separated cpu_set_user_tls.
do not correctly deal with failures. This presently risks deadlock
problems if dependency processing is held up by failures to allocate
a vnode, however, this is better than the situation with the failures.
Sponsored by: Isilon Systems, Inc.
HWPMC_HOOKS is defined. The pmc_cpu_is_*() functions in this file
are referenced unconditionally by hwpmc(4).
This is mostly a stop-gap. The pmc_cpu_is*() function should
probably be declared inline in <sys/pmc.h> or <sys/pmckern.h> and
the function pointers with corresponding SX lock should probably
be moved to another file and compiled conditionally upon HWPMC_HOOKS.
Ok'd by: jkoshy@
Fix a race condition between kern_wait() and thread_stopped().
Problem is in kern_wait(), parent process steps through children list,
once a child process is skipped, and later even if the child is stopped,
parent process still sleeps in msleep(), the race happens if parent
masked SIGCHLD.
Submitted by : Peter Edwards peadar.edwards at gmail dot com
MFC after : 4 days
