an excessive close() on one of these descriptors would cause
a memory for this descriptor to be allocated in the internal
descriptor table. When this descriptor gets used again, e.g.
through the call to open() or socket(), the descriptor would
be erroneously left in the blocking mode, and the whole
application would get stuck on a blocking operation, e.g.,
in accept(2).
Prevent this bug from happening by disallowing close() against
non-active descriptors (return -1 and set errno to EBADF in
this case).
Reviewed by: deischen
Approved by: re (scottl)
to a buffer in the big key/data case, memmove() was used on pointers
to size_ts, but only sizeof(u_int32_t) bytes where copied. This broke
on big_endian architectures where sizeof(size_t) > sizeof(u_int32_t).
This bug broke portupgrade (by way of ruby_bdb1) on sparc64.
Approved by: re (rwatson)
path, making them suitable for direct use by the dynamic loader.
Register libpthread-specific locking API with rtld on startup.
This still has some rough edges with signals which should be
addresses later.
Approved by: re (scottl)
is called and the application is not threaded. This works around
a problem when an application that hasn't yet become threaded
tries to jump out of a signal handler.
Reported by: mbr
Approved by: re@ (rwatson)
condition variables. Cosmetic.
Explicitly compare against PTHREAD_MUTEX_INITIALIZER. We shouldn't
encourage calls to the mutex functions with null pointers to mutexes.
Approved by: re/jhb
from multiple threads don't initialze the same condition variable
more than once.
Explicitly compare cond pointers with PTHREAD_COND_INITIALIZER instead
of NULL. Just because it happens to be defined as NULL is no reason
to encourage the idea that people can call those functions with
NULL pointers to a condition variable.
Approved by: re/jhb
The dead list thread is sufficient for synchronization.
Retire the arch_id (ldt array slot) in the gc thread instead of the
doing it in the thread itself.
Approved by: re/jhb
are not initialized at this place. Move the initializing
before the non-blocking check.
Submitted by: Marius Strobl <marius@alchemy.franken.de>
Reviewed by: jhb
Approved by: re
low-level lock used by the libpthread implementation. In the
future, we'll eliminate spinlocks from libc but that will wait
until after 5.1-release.
Don't call an application signal handler if the handler is
the same as the library-installed handler. This seems to
be possible after a fork and is the cause of konsole hangs.
Approved by: re@ (jhb)
just read() in non-blocking mode too. The reason is obvious. NetBSD
uses a complete different way to get the credentials so this patch
only applies to FreeBSD.
Reviewed by: rwatson
Approved by: re
Remove the special treatment of non-blocking mode in
the "look ahead function" xdrrec_eof(). It currently
assumes that the last read() in a row of several reads
does not have zero lenght. If this is the case, svc_vc_stat()
does return XPRT_MOREREQS, and the RPC-request aborts because
there is no data to read anymore.
To fix this, go back to the original version of the code
for non-blocking mode until NetBSD comes up with another
possible fix like this one in xdrrec_eof()
if (rstrm->last_frag && rstrm->in_finger == rstrm->in_boundry) {
return TRUE;
}
Return always FALSE in set_input_fragment() for non-blocking
mode. Since this was not used in FreeBSD, I omitted it at the
first time. Now we use this function and we should always
return FALSE for it.
Reviewed by: rwatson
Approved by: re
joiner by making sure all locks and unlocks occur in the same order. For
the record the lock order is: DEAD_LIST, THREAD_LIST, exiting thread, joiner
thread.
Approved by: re/rwatson
thread is not dead, the join loop is guaranteed to execute at least
once, so there is no need to pick up the thread list lock after
we return from suspenstion only to release it after the loop.
Approved by: re/blanket libthr
joined and then the joiner thread. There isn't an easy (sane?) way
to make it use the correct order without introducing races involving
the target thread and finding which (active or dead) list it is on. So,
after locking the canceled thread it will try to lock the joined thread
and if it fails release the first lock and try again from the top.
Introduce a new function, _spintrylock, which is simply a wrapper arround
umtx_trylock(), to help accomplish this.
Approved by: re/blanket libthr
Modify the thread creation and thread searching routine
to lock the thread lists with the new locks instead of GIANT_LOCK.
Approved by: re/blanket libthr
list is protected by a spinlock_t, but the dead list uses a pthread_mutex
because it is necessary to synchronize other threads with the garbage
collector thread. Lock/Unlock macros are used so it's easier to make
changes to the locks in the future.
The 'dead thread list' lock is intended to replace the gc mutex.
This doesn't have any practical ramifications. It simply makes it
clearer what the purpose of the lock is. The gc will use this lock,
instead of the gc mutex, to synchronize access to the dead list with
other threads.
Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK,
and also to properly lock and protect thread state changes,
especially with respect to a joining thread.
The gc thread was also re-arranged to be more organized and less nested.
_pthread_join() was also modified to use the thread list locks. However,
locking and unlocking here needs special care because a thread could find
itself in a position where it's joining an exiting thread that is
waiting on the dead list lock, which this thread (joiner) holds. If the
joiner doesn't take care to lock *and* unlock in the same order they
(the joiner and the joinee) could deadlock against each other.
Approved by: re/blanket libthr
pthread_cond_t) internaly in addition to the low-level spinlock_t. The
garbage collector mutex and condition variable are two such examples. This
might lead to critical sections nested within critical sections. Implement
a reference counting mechanism so that signals are masked only on the first
entry and unmasked on the last exit.
I'm not sure I like the idea of nested critical sections, but if
the library is going to use the pthread primitives it might be necessary.
Approved by: re/blanket libthr
a lock is being waitied on.
Fix a races in join and cancellation.
When trying to wait on a CV and the library is not yet
threaded, make it threaded so that waiting actually works.
When trying to nanosleep() and we're not threaded, just
call the system call nanosleep instead of adding the thread
to the wait queue.
Clean up adding/removing new threads to the "all threads queue",
assigning them unique ids, and tracking how many active threads
there are. Do it all when the thread is added to the scheduling
queue instead of making pthread_create() know how to do it.
Fix a race where a thread could be marked for signal delivery
but it could be exited before we actually add the signal to it.
Other minor cleanups and bug fixes.
Submitted by: davidxu
Approved by: re@ (blanket for libpthread)
Access to the thread's flags and state is protected by
_thread_critical_enter/exit(). When a thread is signaled with a condition
its state must be protected by locking it and disabling
signals before it is taken of the waiters' queue.
Move the implementation of pthread_cond_signal() and pthread_cond_broadcast()
into one function, cond_signal(). Its behaviour is determined by the
last argument, int broadcast. If this is set to 1 it will remove all
waiters, otherwise it will wake up only the first waiter thread.
Remove an extraneous call to pthread_testcancel().
Approved by: re/blanket libthr
that take the address of a struct pthread as their first argument.
_spin[un]lock() just become wrappers arround these two functions.
These new functions are for use in situations where curthread can't be
used. One example is _thread_retire(), where we invalidate the array index
curthread uses to get its pointer..
Approved by: re/blanket libthr
Prevent one thread from messing up another thread's saved signal
mask by saving it in struct pthread instead of leaving it as a
global variable. D'oh!
Approved by: re/blanket libthr
in thr_private.h
o Lock down the ldt_entries array and ldt_free, which points to
the next free slot. As noted in the comments, it's necessary
to special case the initial_thread because %gs is not setup
for it yet. This is ok because that early in the program there
won't be any reentrancy issues anyways.
Approved by: re/blanket libthr
When in either the mutex or cond queue we notice that the thread
is already on one of the queues, don't just simply abort(). Print
out the thread's identifiers and what queue it was on.
Approved by: markm/mentor, re/blanket libthr
is the *only* remaining thread in the application, in which case we
should not core dump, and instead exit gracefully.
Approved by: markm/mentor, re/blanket libthr
be external (initialize()!).
Remove cancellation points from _pthread_cond_wait and
_pthread_cond_timedwait (single underscore versions are
libc private functions). Point the weak reference(!) for
these functions to the versions with cancellation points.
Approved by: re@(blanket till 5/19)
Pointed out by: kan (cancellation point bug)
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)
