in the kernel, the sysctl_register() call would fail, as expected.
However, when unloading this module again, the kernel would then panic
in sysctl_unregister(). Print a message error instead.
Submitted by: Nicolai Petri <nicolai@catpipe.net>
Reviewed by: imp
Approved by: re@ (jhb)
buf_start() to avoid triggering a panic in softdep_disk_io_initiation()
if b_iocmd happened to be BIO_READ. The later initialisation of
b_iocmd in cluster_wbuild() could probably be moved to before the
buf_start() call, but this patch keeps the change as simple as
possible.
This is reported to fix occasional "softdep_disk_io_initiation: read"
panics, especially on NFS servers.
Reported by: Nick Hilliard <nick@netability.ie>
Tested by: Nick Hilliard <nick@netability.ie>
Approved by: re (rwatson)
because we could fail due to a small buffer and loop and rerun. If this
happens, then the vsnprintf() will have already taken the arguments off
the va_list. For i386 and others, this doesn't matter because the
va_list type is a passed as a copy. But on powerpc and amd64, this is
fatal because the va_list is a reference to an external structure that
keeps the vararg state due to the more complicated argument passing system.
On amd64, arguments can be passed as follows:
First 6 int/pointer type arguments go in registers, the rest go on
the memory stack.
Float and double are similar, except using SSE registers.
long double (80 bit precision) are similar except using the x87 stack.
Where the 'next argument' comes from depends on how many have been
processed so far and what type it is. For amd64, gcc keeps this state
somewhere that is referenced by the va_list.
I found a description that showed the va_copy was required here:
http://mirrors.ccs.neu.edu/cgi-bin/unixhelp/man-cgi?va_end+9
The single unix spec doesn't mention va_copy() at all.
Anyway, the problem was that the sysctl kern.geom.conf* nodes would panic
due to walking off the end of the va_arg lists in vsnprintf. A better fix
would be to have sbuf_vprintf() use a single pass and call kvprintf()
with a callback function that stored the results and grew the buffer
as needed.
Approved by: re (scottl)
size and the kernel's heap size, specifically, vm_kmem_size. This
function allows a maximum of 40% of the vm_kmem_size to be used for
vnodes and vm objects. This is a conservative bound based upon recent
problem reports. (In other words, a slight increase in this percentage
may be safe.)
Finally, machines with less than ~3GB of RAM should be unaffected
by this change, i.e., the maximum number of vnodes should remain
the same. If necessary, machines with 3GB or more of RAM can increase
the maximum number of vnodes by increasing vm_kmem_size.
Desired by: scottl
Tested by: jake
Approved by: re (rwatson,scottl)
keep the thread state variable consistent with its real state.
i.e. Don't say it's on the run queue when it isn't.
Also clarify the associated comment.
Turns a double panic back to a single panic :-/
Approved by: re@ (jhb)
prime objectives are:
o Implement a syscall path based on the epc inststruction (see
sys/ia64/ia64/syscall.s).
o Revisit the places were we need to save and restore registers
and define those contexts in terms of the register sets (see
sys/ia64/include/_regset.h).
Secundairy objectives:
o Remove the requirement to use contigmalloc for kernel stacks.
o Better handling of the high FP registers for SMP systems.
o Switch to the new cpu_switch() and cpu_throw() semantics.
o Add a good unwinder to reconstruct contexts for the rare
cases we need to (see sys/contrib/ia64/libuwx)
Many files are affected by this change. Functionally it boils
down to:
o The EPC syscall doesn't preserve registers it does not need
to preserve and places the arguments differently on the stack.
This affects libc and truss.
o The address of the kernel page directory (kptdir) had to
be unstaticized for use by the nested TLB fault handler.
The name has been changed to ia64_kptdir to avoid conflicts.
The renaming affects libkvm.
o The trapframe only contains the special registers and the
scratch registers. For syscalls using the EPC syscall path
no scratch registers are saved. This affects all places where
the trapframe is accessed. Most notably the unaligned access
handler, the signal delivery code and the debugger.
o Context switching only partly saves the special registers
and the preserved registers. This affects cpu_switch() and
triggered the move to the new semantics, which additionally
affects cpu_throw().
o The high FP registers are either in the PCB or on some
CPU. context switching for them is done lazily. This affects
trap().
o The mcontext has room for all registers, but not all of them
have to be defined in all cases. This mostly affects signal
delivery code now. The *context syscalls are as of yet still
unimplemented.
Many details went into the removal of the requirement to use
contigmalloc for kernel stacks. The details are mostly CPU
specific and limited to exception_save() and exception_restore().
The few places where we create, destroy or switch stacks were
mostly simplified by not having to construct physical addresses
and additionally saving the virtual addresses for later use.
Besides more efficient context saving and restoring, which of
course yields a noticable speedup, this also fixes the dreaded
SMP bootup problem as a side-effect. The details of which are
still not fully understood.
This change includes all the necessary backward compatibility
code to have it handle older userland binaries that use the
break instruction for syscalls. Support for break-based syscalls
has been pessimized in favor of a clean implementation. Due to
the overall better performance of the kernel, this will still
be notived as an improvement if it's noticed at all.
Approved by: re@ (jhb)
the vnode and restart the loop. Vflush() is vulnerable since it does not
hold a reference to the vnode and it holds no other locks while waiting
for the vnode lock. The vnode will no longer be on the list when the
loop is restarted.
Approved by: re (rwatson)
PT_DETACH ptrace(2) requests from functioning as advertised in the
manual page. As described in kern/35175, the PT_DETACH request will,
under certain circumstances, pass an unwanted signal on to the traced
process upan detaching from it. The PT_CONTINUE request will
sometimes fail if you make it pass a signal that has "properties" that
differ from the properties of the signal that origionally caused the
traced process to be stopped. Since PT_KILL is nothing than
PT_CONTINUE with SIGKILL, it is broken too. In the PT_KILL case, this
leads to an unkillable process.
PR: 44011
Submitted by: Mark Kettenis <kettenis@chello.nl>
Approved by: re(jhb)
netstat(1) not display it for now because its effects are not yet
completely implemented and we're about to cut 5.2-RELEASE.
This is temporary.
Approved by: re (scottl, rwatson)
- Move struct sigacts out of the u-area and malloc() it using the
M_SUBPROC malloc bucket.
- Add a small sigacts_*() API for managing sigacts structures: sigacts_alloc(),
sigacts_free(), sigacts_copy(), sigacts_share(), and sigacts_shared().
- Remove the p_sigignore, p_sigacts, and p_sigcatch macros.
- Add a mutex to struct sigacts that protects all the members of the struct.
- Add sigacts locking.
- Remove Giant from nosys(), kill(), killpg(), and kern_sigaction() now
that sigacts is locked.
- Several in-kernel functions such as psignal(), tdsignal(), trapsignal(),
and thread_stopped() are now MP safe.
Reviewed by: arch@
Approved by: re (rwatson)
don't add the current time to it, but leave it as clear so that when the
timer is disabled, the it_value is always clear.
Reviewed by: bde
Approved by: re (rwatson)
desired buffer is found at one of the roots more than 60% of the time.
Thus, checking both roots before performing either splay eliminates
unnecessary splays on the first tree splayed.
Approved by: re (jhb)
synchronization primitives from inside DDB is generally a bad idea,
and in this case it frequently results in panics due to DDB commands
being executed from the sio fast interrupt context on a serial
console. Replace the locking with a note that a lack of locking
means that DDB may get see inconsistent views of the mount and vnode
lists, which could also result in a panic. More frequently,
though, this avoids a panic than causes it.
Discussed with ages ago: bde
Approved by: re (scottl)
reason for the duplication was that m_freem() was meant to eventually
be optimized to hold the lock of the cache being freed to as long as
possible across frees but the difficulty of implementing said
optimization right now is too high, given that in some cases (see MAC
and non-cluster external buffers), we need to call into other subsytems,
something not permissible when the cache lock is held.
This change minimizes code duplication while keeping at least the
atomic mbuf+cluster free optimization.
Suggested by: luigi
constants in question refer to the number of label slots, not the
maximum number of policies that may be loaded. This should reduce
confusion regarding an element in the MAC sysctl MIB, as well as
make it more clear what the affect of changing the compile-time
constants is.
Approved by: re (jhb)
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
(1) Accept that we're now going to use mutexes, so don't attempt
to avoid treating them as mutexes. This cleans up locking
accessor function names some.
(2) Rename variables to _mtx, _cv, _count, simplifying the naming.
(3) Add a new form of the _busy() primitive that conditionally
makes the list busy: if there are entries on the list, bump
the busy count. If there are no entries, don't bump the busy
count. Return a boolean indicating whether or not the busy
count was bumped.
(4) Break mac_policy_list into two lists: one with the same name
holding dynamic policies, and a new list, mac_static_policy_list,
which holds policies loaded before mac_late and without the
unload flag set. The static list may be accessed without
holding the busy count, since it can't change at run-time.
(5) In general, prefer making the list busy conditionally, meaning
we pay only one mutex lock per entry point if all modules are
on the static list, rather than two (since we don't have to
lower the busy count when we're done with the framework). For
systems running just Biba or MLS, this will halve the mutex
accesses in the network stack, and may offer a substantial
performance benefits.
(6) Lay the groundwork for a dynamic-free kernel option which
eliminates all locking associated with dynamically loaded or
unloaded policies, for pre-configured systems requiring
maximum performance but less run-time flexibility.
These changes have been running for a few weeks on MAC development
branch systems.
Approved by: re (jhb)
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
does the copyin stuff and then calls the second part kern_sendit to do
the hard work. Don't bother holding Giant during the copyin phase.
The intent of this is to allow the Linux emulator to impliment send*
syscalls without using the stackgap.
argument to the functions shm{at,ctl}1 and shm_find_segment_by_shmid{x}.
The BSD semantics didn't allow the usage of shared segment after
being marked for removal through IPC_RMID.
The patch involves the following functions:
- shmat
- shmctl
- shm_find_segment_by_shmid
- shm_find_segment_by_shmidx
- linux_shmat
- linux_shmctl
Submitted by: Orlando Bassotto <orlando.bassotto@ieo-research.it>
Reviewed by: marcel
trustworthy for vnode-backed objects.
- Restore the old behavior of vm_object_page_remove() when the end
of the given range is zero. Add a comment to vm_object_page_remove()
regarding this behavior.
Reported by: iedowse
double free of a mbuf occurs and cause an immediate panic, rather
than allowing free list corruption to occur.
This code is trapped under INVARIANTS, so it should not cause any
change in default performance.
Reviewed by: a bunch of people on -net
MFC after: 1 week
fini routines instead of in fork() and wait(). This has the nice side
benefit that the proc lock of any process on the allproc list is always
valid and sched_lock doesn't have to be used to test against PRS_NEW
anymore.
uptime. Where necessary, convert it back to Unix time by adding boottime
to it. This fixes a potential problem in the accounting code, which would
compute the elapsed time incorrectly if the Unix time was stepped during
the lifetime of the process.
- Eliminate an odd, special-case feature:
if start == end == 0 then all pages are removed. Only one caller
used this feature and that caller can trivially pass the object's
size.
- Assert that the vm_object is locked on entry; don't bother testing
for a NULL vm_object.
- Style: Fix lines that are longer than 80 characters.
- Mark the ktrace() and utrace() syscalls as being MP safe.
- Validate the facs argument to ktrace() prior to doing any vnode
operations or acquiring any locks.
- Share lock the proctree lock over the entire section that calls
ktrsetchildren() and ktrops(). We already did this for process groups.
Doing it for the process case closes a small race where a process might
go away after we look it up. As a result of this, ktrstchildren() now
just asserts that the proctree lock is locked rather than acquiring the
lock itself.
- Add some missing comments to #else and #endif.
syscall return values should be cleared. The system calls
getcontext() and swapcontext() want to return 0 on success
but these contexts can be switched to at a later time so
the return values need to be cleared in the saved register
sets. Other callers of get_mcontext() would normally want
the context without clearing the return values.
Remove the i386-specific context saving from the KSE code.
get_mcontext() is not i386-specific any more.
Fix a bad pointer in the alpha get_mcontext() code. The
context was being bcopy()'d from &td->tf_frame, but tf_frame
is itself a pointer, so the thread was being copied instead.
Spotted by jake.
Glanced at by: jake
Reviewed by: bde (months ago)
Instead of applying the adjustment to processes with a start time of 1,
apply it to all processes with a start time of less than 3600.
None of this would be necessary if the start times were recorded in ticks
instead of seconds and microseconds.
don't include the kernel stacks of swapped-out threads in the page count,
but do include the alternate kernel stack. jhb provided some helpful
comments on this.
PR: 49102
- Add a parameter to vm_pageout_flush() that tells vm_pageout_flush()
whether its caller has locked the vm_object. (This is a temporary
measure to bootstrap vm_object locking.)
whose p_stats->p_start has the magic value 1, replace it with boottime.
Some users were apparently confused by the fact that ps(1) reported a
start time in early 1970 for system processes.
do all the various sigstack dances, unlock the proc lock, and finally do
the copyout. This more closely resembles the behavior of
kern_sigaltstack() and closes a small race.
- Remove Giant from osigstack as it is no longer needed.
rename them appropriately. Protect both flags with both the proc lock
and the sched_lock.
- Protect p_profthreads with the proc lock.
- Remove Giant from profil(2).
- For the 4BSD scheduler, this means that all callers of the static
function resetpriority() now always hold sched_lock, so don't lock
sched_lock explicitly in that function.
kg_nice is now protected by both. Being protected by both means that
other places in the kernel that want to read kg_nice only need one of the
two locks.
their prototypes.
- Remove sched_lock locking from kse_purge() as all callers already lock
the sched_lock before calling it.
- Hold the proc lock slightly longer to protect P_SHOULDSTOP().
o KMF_NOUPCALL
Ask kse_release to not return to userland upcall entry, but instead
direct returns to userland by using current thread's stack and return
address on stack. This flags is intended to be used by UTS in critical
region to wait another UTS thread to leave critical region, by using
kse_release with this flag to avoid spinnng and burning CPU. Also this
flags can be used by UTS to poll completed context when there is nothing
to do in userland and needn't restart from its entry like normal upcall.
o KMF_NOCOMPLETED
Ask kernel to not bring completed thread contexts back to userland when
doing upcall, this flags is intend to be used with above flag when an
upcall thread is in critical region and can not process completed contexts
at that time.
Tested by: deischen
the poll bits when there's actually something in the queue.
Otherwise, select always returned '2' when there were no items to be
read, and '3' when there were. This would preclude being able to read
in a threaded (libc_r) program, as well as checking to see if there
were pending events or not.
lock assertion to it.
- SIGPENDING() no longer needs sched_lock, so only grab sched_lock to set
the TDF_NEEDSIGCHK and TDF_ASTPENDING flags in signotify().
- Add a proc lock assertion to tdsigwakeup().
- Since we always set TDF_OLDMASK while holding the proc lock, the proc
lock is sufficient protection to check its state in postsig() and we only
need sched_lock when clearing the actual flag.
a process group.
- Call pgadjustjobc() twice in fixjobc() to avoid code duplication and
improve readability.
- Use the proc lock to protect P_SHOULDSTOP() instead of sched_lock.
- Check to see if a process is PRS_NEW with sched_lock before trying to
lock its proc lock since the lock may not be constructed yet.
since they are going on the current cpu and not their previously assigned
cpu.
- sched_runnable() should only return true in the SMP case if the other
processor has more than one thread that is runnable. We can not steal
curthread.
- Change kseq_print() to accept the cpuid instead of a kseq pointer. This
makes use of this function in ddb much easier.
the process and session. Instead, cache a true reference to the session
when we do the hold and release our reference on that session. This avoids
the need for the proc lock when dropping the reference.
protects, so don't bother locking it while we assign it to a ucred's
cr_prison.
- Fully construct the new credential for a process before assigning it to
p_ucred.
- Set p_acflag earlier while already hold the proc lock in fork1().
- Mark the realitexpire() callout MPSAFE for new processes. It was already
marked safe for proc0 a long while ago.
generation number back to a long (sizeof(u_int) != sizeof(long) on
sparc64). The alternative would have been to heavily change the libdevstat API.
Discussed with: phk, ken
don't try and convert the argument flags to malloc flags, or we risk
implicitly requesting blocking and generating witness warnings.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
When enabled, this causes m_defrag to randomly return NULL (following
its normal failure case so that extra memory leaks are not introduced.)
Code similar to this was used to find / fix a few bugs last week.
returning some additional room in the first mbuf in a chain, and
avoiding feature-specific contents in the mbuf header. To do this:
- Modify mbuf_to_label() to extract the tag, returning NULL if not
found.
- Introduce mac_init_mbuf_tag() which does most of the work
mac_init_mbuf() used to do, except on an m_tag rather than an
mbuf.
- Scale back mac_init_mbuf() to perform m_tag allocation and invoke
mac_init_mbuf_tag().
- Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since
m_tag's are now GC'd deep in the m_tag/mbuf code rather than
at a higher level when mbufs are directly free()'d.
- Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related
notions.
- Generally change all references to mbuf labels so that they use
mbuf_to_label() rather than &mbuf->m_pkthdr.label. This
required no changes in the MAC policies (yay!).
- Tweak mbuf release routines to not call mac_destroy_mbuf(),
tag destruction takes care of it for us now.
- Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() --
the existing m_tag support does all this for us. Note that
we can no longer just zero the m_tag list on the target mbuf,
rather, we have to delete the chain because m_tag's will
already be hung off freshly allocated mbuf's.
- Tweak m_tag copying routines so that if we're copying a MAC
m_tag, we don't do a binary copy, rather, we initialize the
new storage and do a deep copy of the label.
- Remove use of MAC_FLAG_INITIALIZED in a few bizarre places
having to do with mbuf header copies previously.
- When an mbuf is copied in ip_input(), we no longer need to
explicitly copy the label because it will get handled by the
m_tag code now.
- No longer any weird handling of MAC labels in if_loop.c during
header copies.
- Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test.
In mac_test, handle the label==NULL case, since it can be
dynamically loaded.
In order to improve performance with this change, introduce the notion
of "lazy MAC label allocation" -- only allocate m_tag storage for MAC
labels if we're running with a policy that uses MAC labels on mbufs.
Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS
flag in their load-time flags field during declaration. Note: this
opens up the possibility of post-boot policy modules getting back NULL
slot entries even though they have policy invariants of non-NULL slot
entries, as the policy might have been loaded after the mbuf was
allocated, leaving the mbuf without label storage. Policies that cannot
handle this case must be declared as NOTLATE, or must be modified.
- mac_labelmbufs holds the current cumulative status as to whether
any policies require mbuf labeling or not. This is updated whenever
the active policy set changes by the function mac_policy_updateflags().
The function iterates the list and checks whether any have the
flag set. Write access to this variable is protected by the policy
list; read access is currently not protected for performance reasons.
This might change if it causes problems.
- Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update
function to assert appropriate locks.
- This makes allocation in mac_init_mbuf() conditional on the flag.
Reviewed by: sam
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
mbuf_to_label(). This permits the vast majority of entry point code
to be unaware that labels are stored in m->m_pkthdr.label, such that
we can experiment storage of labels elsewhere (such as in m_tags).
Reviewed by: sam
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
the current queue if its priority is really elevated. This needs more work
as there are cases where a next queue kse could be holding up what would
be a curr queue kse, and thus hurting interactivity. Also, when a thread
with an elevated priority has its priority lowered it should be placed
back on the next queue.
the target process exiting which causes attempts to register the kevent
to randomly fail depending on whether the target runs to completion before
the parent can call kevent(2). The bug actually effects EVFILT_PROC
events on any zombie process, but the most common manifestation is with
parents trying to monitor child processes.
MFC after: 2 weeks
Sponsored by: NTT Multimedia Communications Labs
