that name as a variable. Use mtx_owned(&Giant) where appropriate
instead.
- Proc locking.
- P_FOO -> PS_FOO.
- Update comments about enable interrupts during trap and why this may be
bad if we trap while holding a spin mutex.
- Don't bother resetting p to curproc in syscall() in case we are the child
returning from fork. The child hasn't returned from fork through syscall
in a while.
- Remove fork_return() as it has been superseded by the MI version.
the alpha mp_machdep.c.
- Proc locking.
- Catch up to the P_FOO -> PS_FOO proc flags changes.
- Stick ap_init()'s prototype with the other prototypes.
- Remove the Xforwardirq IPI.
- Remove unused simplelocks.
- Don't try to psignal() from forward_statclock(), but set the appropriate
signal pending flag in p_sflag instead.
- Add in KTR_SMP tracepoints for various SMP functions. (Brought over
from the alpha port)
calls returning EACCES instead of EPERM. This patch modifies vaccess()
to return EPERM instead of EACCES if VADMIN is among the requested
rights. This affects functions normally limited to the owners of
a file, such as chmod(), as EPERM is the error indicating that
privilege would allow the operation, rather than a chance in mandatory
or discretionary rights.
Reported by: bde
inline functions non-inlined. Hide parts of the mutex implementation that
should not be exposed.
Make sure that WITNESS code is not executed during boot until the mutexes
are fully initialized by SI_SUB_MUTEX (the original motivation for this
commit).
Submitted by: peter
interrupt threads to run with it always >= 1, so that malloc can
detect M_WAITOK from "interrupt" context. This is also necessary
in order to context switch from sched_ithd() directly.
Reviewed By: peter
initialization until after malloc() is safe to call, then iterate through
all mutexes and complete their initialization.
This change is necessary in order to avoid some circular bootstrapping
dependencies.
for SMP; just use the same ones as UP. These weren't used without
holding Giant anyway, and the routines that use them would have to
be protected from pre-emption to avoid migrating cpus.
calls it rather than obtaining and releasing it a lot in proc_compare.
- Collect all of the data gathering and stick it just after the
proc_compare loop. This way, we only have to grab sched_lock once now
when handling SIGINFO. All the printf's are done after the values are
calculated.
Submitted mostly by: bde
The counters are incremented when a thread goes to sleep and decremented
either when a thread is woken up by another thread or when the sleep
times out. There existed a race where the sleep count could be decremented
twice resulting in an eventual underflow.
Move the decrementing of the "counters" to the thread initiating the sleep
and thus remedy the problem.
SIGXCPU signal, and killing of processes that exceed their allowed run
time until they can play nice with sched_lock. Right now they are just
potentital panics waiting to happen. The printf() has bitten several
people.
not hold sched_lock while calling ttyprintf(). If we are on a serial
console, then ttyprintf() will end up getting the sio lock, resulting in
a lock order violation.
Noticed by: des
This is an odd one. This patch appears to fix a panic related to background
bitmap writes (for FFS), though neither Kirk, Ian, or I can figure out how
B_CLUSTEROK could possibly be set on a bitmap block to cause the clustering
code to improperly cluster with a buffer undergoing a background write.
In anycase, the clustering code is very fragile and this patch helps with
that, as well as possibly fixing a bug Andre was having.
Suggested by: Ian Dowse <iedowse@maths.tcd.ie>
Testing by: Andre Albsmeier <andre.albsmeier@mchp.siemens.de>
All calls to mtx_init() for mutexes that recurse must now include
the MTX_RECURSE bit in the flag argument variable. This change is in
preparation for an upcoming (further) mutex API cleanup.
The witness code will call panic() if a lock is found to recurse but
the MTX_RECURSE bit was not set during the lock's initialization.
The old MTX_RECURSE "state" bit (in mtx_lock) has been renamed to
MTX_RECURSED, which is more appropriate given its meaning.
The following locks have been made "recursive," thus far:
eventhandler, Giant, callout, sched_lock, possibly some others declared
in the architecture-specific code, all of the network card driver locks
in pci/, as well as some other locks in dev/ stuff that I've found to
be recursive.
Reviewed by: jhb
allocation routines are being called safely. Since we drop our relevant
mbuf mutex and acquire Giant before we call kmem_malloc(), we have
to make sure that this does not pave the way for a fatal lock order
reversal. Check that either Giant is already held (in which case it's safe
to grab it again and recurse on it) or, if Giant is not held, that no
other locks are held before we try to acquire Giant.
Similarily, add a KASSERT valid in the WITNESS case in m_reclaim() to
nail callers who end up in m_reclaim() and hold a lock.
Pointed out by: jhb
while we are copying it to the kinfo_proc structure.
- Test against p_stat to see if we are blocked on a mutex.
- Terminate ki_mtxname with a null char rather than ki_wmesg.
m_reclaim() and re-acquire it when m_reclaim() returns. This means that
we now call the drain routines without holding the mutex lock and
recursing into it. This was done for mainly two reasons:
(i) Avoid the long recursion; long recursions are typically bad and this
is the case here because we block all other code from freeing mbufs
if they need to. Doing that is kind of counter-productive, since we're
really hoping that someone will free.
(ii) More importantly, avoid a potential lock order reversal. Right now,
not all the locks have been added to our networking code; but
without this change, we're introducing the possibility for deadlock.
Consider for example ip_drain(). We will likely eventually introduce
a lock for ipq there, and so ip_freef() will be called with ipq lock
held. But, ip_freef() calls m_freem() which in turn acquires the
mmbfree lock. Since we were previously calling ip_drain() with mmbfree
held, our lock order would be: mmbfree->ipq->mmbfree. Some other code
may very well lock ipq first and then call ip_freef(). This would
result in the regular lock order, ipq->mmbfree. Clearly, we have
deadlock if one thread acquires the ipq lock and sits waiting for
mmbfree while another thread calling m_reclaim() acquires mmbfree
and sits waiting for the ipq lock.
Also, make sure to add a comment above m_reclaim()'s definition briefly
explaining this. Also document this above the call to m_reclaim() in
m_mballoc_wait().
Suggested and reviewed by: alfred
the pipe, then we were corrupting the pipe_zone free list by calling
pipeclose on rpipe twice. NULL out rpipe to avoid this.
Reviewed by: dillon
Reviewed by: iedowse
