freed belong to the kernel object.)
- Increase the granularity of the vm object locking in vm_hold_load_pages()
in order to reduce the number of times that we acquire and release the
same lock.
Doing so creates a race where the buf is on neither list.
- Only vfree() in an error case in vclean() if VSHOULDFREE() thinks we
should.
- Convert the error case in vclean() to INVARIANTS from DIAGNOSTIC as this
really should not happen and is fast to check.
special signal-delivery protections for setugid processes. In the
event that a system is relying on "unusual" signal delivery to
processes that change their credentials, this can be used to work
around application problems.
Also, add SIGALRM to the set of signals permitted to be delivered to
setugid processes by unprivileged subjects.
Reported by: Joe Greco <jgreco@ns.sol.net>
pmap_extract_and_hold(). Note, however, that GIANT_REQUIRED should not be
removed until all platforms fully implement the "prot" parameter to
pmap_extract_and_hold().
Reviewed by: tegge
about interrupt trigger mode and interrupt polarity. This allows ACPI
for example to pass interrupt resource information up the hierarchy.
The default implementation of the method therefore is to pass the
request to the parent.
Reviewed by: jhb, njl
specified directory is not found in the mount list. Before the
MNT_BYFSID changes, unmount(2) used to return ENOENT for a nonexistent
path and EINVAL for a non-mountpoint, but we can no longer distinguish
between these cases. Of the two error codes, EINVAL was more likely
to occur in practice, and it was the only one of the two that was
documented.
Update the manual page to match the current behaviour.
Suggested by: tjr
Reviewed by: tjr
and/or INTR_FAST. This belongs elsehwere and perhaps under bootverbose;
I'm committing it for now as it's uesful to know which drivers have
been converted and which have not.
out of cdregister() and daregister(), which are run from interrupt context.
The sysctl code does blocking mallocs (M_WAITOK), which causes problems
if malloc(9) actually needs to sleep.
The eventual fix for this issue will involve moving the CAM probe process
inside a kernel thread. For now, though, I have fixed the issue by moving
dynamic sysctl variable creation for these two drivers to a task queue
running in a kernel thread.
The existing task queues (taskqueue_swi and taskqueue_swi_giant) run in
software interrupt handlers, which wouldn't fix the problem at hand. So I
have created a new task queue, taskqueue_thread, that runs inside a kernel
thread. (It also runs outside of Giant -- clients must explicitly acquire
and release Giant in their taskqueue functions.)
scsi_cd.c: Remove sysctl variable creation code from cdregister(), and
move it to a new function, cdsysctlinit(). Queue
cdsysctlinit() to the taskqueue_thread taskqueue once we
have fully registered the cd(4) driver instance.
scsi_da.c: Remove sysctl variable creation code from daregister(), and
move it to move it to a new function, dasysctlinit().
Queue dasysctlinit() to the taskqueue_thread taskqueue once
we have fully registered the da(4) instance.
taskqueue.h: Declare the new taskqueue_thread taskqueue, update some
comments.
subr_taskqueue.c:
Create the new kernel thread taskqueue. This taskqueue
runs outside of Giant, so any functions queued to it would
need to explicitly acquire/release Giant if they need it.
cd.4: Update the cd(4) man page to talk about the minimum command
size sysctl/loader tunable. Also note that the changer
variables are available as loader tunables as well.
da.4: Update the da(4) man page to cover the retry_count,
default_timeout and minimum_cmd_size sysctl variables/loader
tunables. Remove references to /dev/r???, they aren't used
any longer.
cd.9: Update the cd(9) man page to describe the CD_Q_10_BYTE_ONLY
quirk.
taskqueue.9: Update the taskqueue(9) man page to describe the new thread
task queue, and the taskqueue_swi_giant queue.
MFC after: 3 days
Changes from the original implementation:
- Fragmentation is handled by the function m_fragment, which can
be called from whereever fragmentation is needed. Note that this
function is wrapped in #ifdef MBUF_STRESS_TEST to discourage non-testing
use.
- m_fragment works slightly differently from the old fragmentation
code in that it allocates a seperate mbuf cluster for each fragment.
This defeats dma_map_load_mbuf/buffer's feature of coalescing adjacent
fragments. While that is a nice feature in practice, it nerfed the
usefulness of mbuf_stress_test.
- Add two modes of random fragmentation. Chains with fragments all of
the same random length and chains with fragments that are each uniquely
random in length may now be requested.
o remove irrlevant spl
Notes:
1. We don't lock domain list traversals as this is safe until we start
removing domains.
2. The calculation of max_datalen in net_init_domain appears safe as
noone depends on max_hdr and max_datalen having consistent values.
3. Giant is still held for fast and slow timeouts; this must stay until
each timeout routine is properly locked (coming soon).
Sponsored by: FreeBSD Fondation
bail out if the buffer is not already present.
- The buffer returned by incore() is not locked and should not be sent to
brelse(). Use getblk() with the new GB_NOCREAT flag to preserve the
desired semantics.
sockets into machine-dependent files. The rationale for this
migration is illustrated by the modified amd64 allocator. It uses the
amd64's direct map to avoid emphemeral mappings in the kernel's
address space. On an SMP, the emphemeral mappings result in an IPI
for TLB shootdown for each transmitted page. Yuck.
Maintainers of other 64-bit platforms with direct maps should be able
to use the amd64 allocator as a reference implementation.
- Surround all accesses of the BKGRD{WAIT,INPROG} flags with the vnode
interlock.
- Don't use the B_LOCKED flag and QUEUE_LOCKED for background write
buffers. Check for the BKGRDINPROG flag before recycling or throwing
away a buffer. We do this instead because it is not safe for us to move
the original buffer to a new queue from the callback on the background
write buffer.
- Remove the B_LOCKED flag and the locked buffer queue. They are no longer
used.
- The vnode interlock is used around checks for BKGRDINPROG where it may
not be strictly necessary. If we hold the buf lock the a back-ground
write will not be started without our knowledge, one may only be
completed while we're not looking. Rather than remove the code, Document
two of the places where this extra locking is done. A pass should be
done to verify and minimize the locking later.
mac_reflect_mbuf_icmp()
mac_reflect_mbuf_tcp()
These entry points permit MAC policies to do "update in place"
changes to the labels on ICMP and TCP mbuf headers when an ICMP or
TCP response is generated to a packet outside of the context of
an existing socket. For example, in respond to a ping or a RST
packet to a SYN on a closed port.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
explicit access control checks to delete and list extended attributes
on a vnode, rather than implicitly combining with the setextattr and
getextattr checks. This reflects EA API changes in the kernel made
recently, including the move to explicit VOP's for both of these
operations.
Obtained from: TrustedBSD PRoject
Sponsored by: DARPA, Network Associates Laboratories
MAC_DEBUG_COUNTER_INC() and MAC_DEBUG_COUNTER_DEC() to maintain
debugging counter values rather than #ifdef'ing the atomic
operations to MAC_DEBUG.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
represents the pruely stylistic changes and should have no net impact
on the rest of the code.
bde's more substantive changes will follow in a separate commit once
we've come to closure on them.
Submitted by: bde
ntp_update_second twice when we have a large step in case that step
goes across a scheduled leap second. The only way this could happen
would be if we didn't call tc_windup over the end of day on the day of
a leap second, which would only happen if timeouts were delayed for
seconds. While it is an edge case, it is an important one to get
right for my employer.
Sponsored by: Timing Solutions Corporation
prototypes of cpu_halt(), cpu_reset() and swi_vm() from md_var.h to
cpu.h. This affects db_command.c and kern_shutdown.c.
ia64: move all MD prototypes from cpu.h to md_var.h. This affects
madt.c, interrupt.c and mp_machdep.c. Remove is_physical_memory().
It's not used (vm_machdep.c).
alpha: the MD prototypes have been left in cpu.h with a comment
that they should be there. Moving them is left for later. It was
expected that the impact would be significant enough to be done in
a seperate commit.
powerpc: MD prototypes left in cpu.h. Comment added.
Suggested by: bde
Tested with: make universe (pc98 incomplete)
A timecounter will be selected when registered if its quality is
not negative and no less than the current timecounters.
Add a sysctl to report all available timecounters and their qualities.
Give the dummy timecounter a solid negative quality of minus a million.
Give the i8254 zero and the ACPI 1000.
The TSC gets 800, unless APM or SMP forces it negative.
Other timecounters default to zero quality and thereby retain current
selection behaviour.
- Update some stale comments.
- Sort a couple of includes.
- Only set 'newcpu' in updatepri() if we use it.
- No functional changes.
Obtained from: bde (via an old diff I got a long time ago)
check for permissions, do it for all requests, not the known requests.
Later when we actually service the request we deal with the invalid
requests we previously caught earlier.
This commit changes the behaviour of the ptrace(2) interface for
boundary cases such as an unknown request without proper permissions.
Previously we would return EINVAL. Now we return EBUSY or EPERM.
Platforms need to define __HAVE_PTRACE_MACHDEP when they have MD
requests. This makes the prototype of cpu_ptrace() visible and
introduces a call to this function for all requests greater or
equal to PT_FIRSTMACH.
Silence on: audit
kobj global method table; also kassert that the table has not overflowed
when defining a new method.
there are indications that the table is being overflowed in certain
situations as we gain more kobj consumers- this will allow us to check
whether kobj is at fault. symptoms would be incorrect methods being called.
cpu_switch() where both the old and new threads are passed in as
arguments. Only powerpc uses the old conventions now.
- Update comments in the Alpha swtch.s to reflect KSE changes.
Tested by: obrien, marcel
- All those diffs to syscalls.master for each architecture *are*
necessary. This needed clarification; the stub code generation for
mlockall() was disabled, which would prevent applications from
linking to this API (suggested by mux)
- Giant has been quoshed. It is no longer held by the code, as
the required locking has been pushed down within vm_map.c.
- Callers must specify VM_MAP_WIRE_HOLESOK or VM_MAP_WIRE_NOHOLES
to express their intention explicitly.
- Inspected at the vmstat, top and vm pager sysctl stats level.
Paging-in activity is occurring correctly, using a test harness.
- The RES size for a process may appear to be greater than its SIZE.
This is believed to be due to mappings of the same shared library
page being wired twice. Further exploration is needed.
- Believed to back out of allocations and locks correctly
(tested with WITNESS, MUTEX_PROFILING, INVARIANTS and DIAGNOSTIC).
PR: kern/43426, standards/54223
Reviewed by: jake, alc
Approved by: jake (mentor)
MFC after: 2 weeks
From alc:
Move pageable pipe memory to a seperate kernel submap to avoid awkward
vm map interlocking issues. (Bad explanation provided by me.)
From me:
Rework pipespace accounting code to handle this new layout, and adjust
our default values to account for the fact that we now have a solid
limit on allocations.
Also, remove the "maxpipes" limit, as it no longer has a purpose.
(The limit on kva usage solves the problem of having two many pipes.)
application could cause a wired page to be freed. In general,
vm_page_hold() should be preferred for ephemeral kernel mappings of pages
borrowed from a user-level address space. (vm_page_wire() should really be
reserved for indefinite duration pinning by the "owner" of the page.)
Discussed with: silby
Submitted by: tegge
psignal()/tdsignal(). The test was historically in psignal(). It was
changed into a KASSERT, and then later moved to tdsignal() when the
latter was introduced.
Reviewed by: iedowse, jhb
ioctls.
In the particular case of ptrace(), this commit more-or-less reverts
revision 1.53 of sys_process.c, which appears to have been erroneous.
Reviewed by: iedowse, jhb
a reference to the containing object. The purpose of the reference
being to prevent the destruction of the object and an attempt to free
the wired page. (Wired pages can't be freed.) Unfortunately, this
approach does not work. Some operations, like fork(2) that call
vm_object_split(), can move the wired page to a difference object,
thereby making the reference pointless and opening the possibility
of the wired page being freed.
A solution is to use vm_page_hold() in place of vm_page_wire(). Held
pages can be freed. They are moved to a special hold queue until the
hold is released.
Submitted by: tegge
semaphore and doing so can lead to a possible reversal. WITNESS would have
caught this if semaphores were used more often in the kernel.
Submitted by: Ted Unangst <tedu@stanford.edu>, Dawson Engler
connection is to be established asynchronously, behave as in the
case of non-blocking mode:
- keep the SS_ISCONNECTING bit set thus indicating that
the connection establishment is in progress, which is the case
(clearing the bit in this case was just a bug);
- return EALREADY, instead of the confusing and unreasonable
EADDRINUSE, upon further connect(2) attempts on this socket
until the connection is established (this also brings our
connect(2) into accord with IEEE Std 1003.1.)
than i386 or AMD64, TP register points to thread mailbox, and they can not
atomically clear km_curthread in kse mailbox, in this case, thread retrieves
its thread pointer from TP register and sets flag TMF_NOUPCALL in its thread
mailbox to indicate a critical region.
use vrele() instead of vput() on the parent directory vnode returned
by namei() in the case where it is equal to the target vnode. This
handles namei()'s somewhat strange (but documented) behaviour of
not locking either vnode when the two vnodes are equal and LOCKPARENT
but not LOCKLEAF is specified.
Note that since a vnode double-unlock is not currently fatal, these
coding errors were effectively harmless.
Spotted by: Juergen Hannken-Illjes <hannken@eis.cs.tu-bs.de>
Reviewed by: mckusick
malloc and mbuf allocation all not requiring Giant.
1) ostat, fstat and nfstat don't need Giant until they call fo_stat.
2) accept can copyin the address length without grabbing Giant.
3) sendit doesn't need Giant, so don't bother grabbing it until kern_sendit.
4) move Giant grabbing from each indivitual recv* syscall to recvit.
support routines in kern_acl.c:
- Define ACL_OVERRIDE_MASK and ACL_PRESERVE_MASK centrally in acl.h: the
mode bits that are (and aren't) stored in the ACL.
- Add acl_posix1e_acl_to_mode(): given a POSIX.1e extended ACL, generate
a compatibility mode (only the bits supported by the POSIX.1e ACL).
- acl_posix1e_newfilemode(): Given a requested creation mode and default
ACL, calculate the mode for the new file system object (only the bits
supported by the POSIX.1e ACL).
PR: 50148
Reported by: Ritz, Bruno <bruno_ritz@gmx.ch>
Obtained from: TrustedBSD Project
another thread. We use the td_oncpu member of the other field to locate
it's associated CPU and then search the that CPU's list of spin locks
contained in its per-CPU data. This is not always safe and may in fact
panic or just not work, but it is useful in at least one case.
on a non-blocking pipe in cases where select(2) returns the file
descriptor as ready for write. This in turns causes libc_r, for
one, to busy wait in such cases.
Note: it is a quick performance fix, a more complex fix might be
required in case this turns out to have unexpected side effects.
Reviewed by: silby
MFC after: 3 days
thread's pid to make debugging easier for people who don't want to have to
use the intended tool for these panics (witness).
Indirectly prodded by: kris
a long-standing mistake in the way a portion of a pipe's KVA is
allocated. Specifically, kmem_alloc_pageable() is inappropriate
for use in the "direct" case because it allows a preceding vm map entry
and vm object to be extended to support the new KVA allocation.
However, the direct case KVA allocation should not have a backing
vm object. This is corrected by using kmem_alloc_nofault().
Submitted by: tegge (with the above explanation by me)
kernel ACL interfaces and system call names.
Break out UFS2 and FFS extattr delete and list vnode operations from
setextattr and getextattr to deleteextattr and listextattr, which
cleans up the implementations, and makes the results more readable,
and makes the APIs more clear.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
kern.file sysctl, don't return information about processes that
fail p_cansee(td, p). This prevents sockstat and related
programs from seeing file descriptors owned by processes not
in the same jail as the thread, as well as having implications
for MAC, etc.
This is a partial solution: it permits an information leak about
the number of descriptors in the sizing calculation (but this is
not new information, you can also get it from kern.openfiles),
and doesn't attempt to mask file descriptors based on the
properties of the descriptor, only the process referencing it.
However, it provides most of what you want under most
circumstances, without complicating the locking.
PR: 54211
Based on a patch submitted by: Pawel Jakub Dawidek <nick@garage.freebsd.pl>
contain the filedescriptor number on opens from userland.
The index is used rather than a "struct file *" since it conveys a bit
more information, which may be useful to in particular fdescfs and /dev/fd/*
For now pass -1 all over the place.
comes across it, it will turn into a core dump in userland instead of
a kernel panic. I had also inverted the sense of the test, so
Double pointy hat to: mtm
- Make m_prepend use m_gethdr instead of m_get where
appropriate
- Make m_copym use m_gethdr instead of m_get where
appropriate
- Add a call to m_fixhdr in m_defrag; m_defrag can't
deal with corrupted pkthdr.len counts.
MFC after: 3 days
do not clear the `sb_sel' member of the sockbuf structure
while invalidating the receive sockbuf in sorflush(), called
from soshutdown().
The panic was reproduceable from user land by attaching a knote
with EVFILT_READ filters to a socket, disabling further reads
from it using shutdown(2), and then closing it. knote_remove()
was called to remove all knotes from the socket file descriptor
by detaching each using its associated filterops' detach call-
back function, sordetach() in this case, which tried to remove
itself from the invalidated sockbuf's klist (sb_sel.si_note).
PR: kern/54331
When a signal is being delivered to process, first find a sigwait
thread to deliver, POSIX's argument is speed of delivering signal
to sigwait thread is faster than other ways. A signal in its wait
set will cause sigwait to return the signal number, a signal not
in its wait set but in not blocked by the thread also causes sigwait
to return, but sigwait returns EINTR, sigwait is oneshot operation,
only one signal can be delivered to its wait set, when a signal is
delivered to the sigwait thread, the thread's sigwait state is canceled.
an appropriate error number after a failure condition.
In particular, three of the changed statements return ESRCH for a
failed pfind(), and in also three places a non-zero return
from p_cansee() will be passed back,
Also noticed by: rwatson
1. There was a race condition between a thread unlocking
a umtx and the thread contesting it. If the unlocking
thread won the race it may try to wakeup a thread that
was not yet in msleep(). The contesting thread would then
go to sleep to await a wakeup that would never come. It's
not possible to close the race by using a lock because
calls to casuptr() may have to fault a page in from swap.
Instead, the race was closed by introducing a flag that
the unlocking thread will set when waking up a thread.
The contesting thread will check for this flag before
going to sleep. For now the flag is kept in td_flags,
but it may be better to use some other member or create
a new one because of the possible performance/contention
issues of having to own sched_lock. Thanks to jhb for
pointing me in the right direction on this one.
2. Once a umtx was contested all future locks and unlocks
were happening in the kernel, regardless of whether it
was contested or not. To prevent this from happening,
when a thread locks a umtx it checks the queue for that
umtx and unsets the contested bit if there are no other
threads waiting on it. Again, this is slightly more
complicated than it needs to be because we can't hold
a lock across casuptr(). So, the thread has to check
the queue again after unseting the bit, and reset the
contested bit if it finds that another thread has put
itself on the queue in the mean time.
3. Remove the if... block for unlocking an uncontested
umtx, and replace it with a KASSERT. The _only_ time
a thread should be unlocking a umtx in the kernel is
if it is contested.
large to huge amounts of small or medium sized receive buffers. The problem
with these situations is that they eat up the available DMA address space
very quickly when using mbufs or even mbuf clusters. Additionally this
facility provides a direct mapping between 32-bit integers and these buffers.
This is needed for devices originally designed for 32-bit systems. Ususally
the virtual address of the buffer is used as a handle to find the buffer as
soon as it is returned by the card. This does not work for 64-bit machines
and hence this mapping is needed.
multiple mutex pools with different options and sizes. Mutex pools can
be created with either the default sleep mutexes or with spin mutexes.
A dynamically created mutex pool can now be destroyed if it is no longer
needed.
Create two pools by default, one that matches the existing pool that
uses the MTX_NOWITNESS option that should be used for building higher
level locks, and a new pool with witness checking enabled.
Modify the users of the existing mutex pool to use the appropriate pool
in the new implementation.
Reviewed by: jhb
immediately after the kernel map has been sized, and is
the optimal place for the autosizing of memory allocations
which occur within the kernel map to occur.
Suggested by: bde
- Use atomic ops to update the bigpipe count
- Make the bigpipe count sysctl readable
- Remove a duplicate comparison in an if statement
- Comment two SYSCTLs.
than the shortcircuited version I had been using, which only worked
properly on i386 & amd64.
Also, change an autoscale constant to account for the more correct
kmem_map size.
Problem noticed by: mux
- Limit the total number of pipes so that we do not
exhaust all vm objects in the kernel map. When
this limit is reached, a ratelimited message will
be printed to the console.
- Put a soft limit on the amount of memory consumable
by pipes. Once the limit has been reached, all new
pipes will be limited to 4K in size, rather than the
default of 16K.
- Put a limit on the number of pages that may be used
for high speed page flipping in order to reduce the
amount of wired memory. Pipe writes that occur
while this limit is exceeded will fall back to
non-page flipping mode.
The above values are auto-tuned in subr_param.c and
are scaled to take into account both the size of
physical memory and the size of the kernel map.
These limits help to reduce the "kernel resources exhausted"
panics that could be caused by opening a large
number of pipes. (Pipes alone are no longer able
to exhaust all resources, but other kernel memory hogs
in league with pipes may still be able to do so.)
PR: 53627
Ideas / comments from: hsu, tjr, dillon@apollo.backplane.com
MFC after: 1 week
