sofree(), as a number of protocols expect to be able to call
soisdisconnected() during detach. That may not be a good assumption,
but until I'm sure if it's a good assumption or not, allow it.
vfs_rel() on the mountpoint if the MAC checks fail in kern_statfs() and
kern_fstatfs(). Similarly, don't perform an extra vfs_rel() if we get
a doomed vnode in kern_fstatfs(), and handle the case of mp being NULL
(for some doomed vnodes) by conditionalizing the vfs_rel() in
kern_fstatfs() on mp != NULL.
CID: 1517
Found by: Coverity Prevent (tm) (kern_fstatfs())
Pointy hat to: jhb
eliminating a second set of identical mutex operations at the bottom.
This allows brief exceeding of the max sockets limit, but only by
sockets in the last stages of being torn down.
- If we fail to register the system call during MOD_LOAD, then note that
so that we don't try to deregister it or invoke the chained event handler
during the subsequent MOD_UNLOAD event. Doing the deregister when the
register failed could result in trashing system call entries.
- Add a SI_SUB_SYSCALLS just before starting up init and use that to
register syscall modules instead of SI_SUB_DRIVERS. Registering system
calls as late as possible increases the chances that any other module
event handlers or SYSINITs in a module are executed to initialize the
data in a kld before a syscall dependent on that data is able to be
invoked.
MFC after: 3 days
longer referenced by other threads (hence our freeing it), we don't need
to set the can't send and can't receive flags, wake up the consumers,
perform two levels of locking, etc. Implement a fast-path teardown,
sbdestroy(), which flushes and releases each socket buffer. A manual
dom_dispose of the receive buffer is still required explicitly to GC
any in-flight file descriptors, etc, before flushing the buffer.
This results in a 9% UP performance improvement and 16% SMP performance
improvement on a tight loop of socket();close(); in micro-benchmarking,
but will likely also affect CPU-bound macro-benchmark performance.
UNIX domain socket at the same time as the remote host is closing the
new connections as quickly as they open. Since the connect() and
send() paths are non-atomic with respect to another, it is possible
for the second thread's close() call to disconnect the two sockets
as connect() returns, leading to the consumer (which plans to send())
with a NULL kernel pointer to its proposed peer. As a result, after
acquiring the UNIX domain socket subsystem lock, we need to revalidate
the connection pointers even though connect() has technically succeed,
and reurn an error to say that there's no connection on which to
perform the send.
We might want to rethink the specific errno number, perhaps ECONNRESET
would be better.
PR: 100940
Reported by: Young Hyun <youngh at caida dot org>
MFC after: 2 weeks
MFC note: Some adaptation will be required
mark system calls as being MPSAFE:
- Stop conditionally acquiring Giant around system call invocations.
- Remove all of the 'M' prefixes from the master system call files.
- Remove support for the 'M' prefix from the script that generates the
syscall-related files from the master system call files.
- Don't explicitly set SYF_MPSAFE when registering nfssvc.
a count of all non-spin locks, not just lockmgr locks. This can give us a
much cheaper way to see if we have any locks held (such as when returning
to userland via userret()) without requiring WITNESS.
MFC after: 1 week
kern_fstatfs() so that it is still held when prison_enforce_statfs() is
called (since that function likes to poke and prod at the mountpoint
structure).
MFC after: 3 days
all other mtx_lock() operations to block. Previously, when the mutex was
destroyed, it would still have a valid value in mtx_lock(): either the
unowned cookie, which would allow a subsequent mtx_lock() to succeed, or a
pointer to the thread who destroyed the mutex if the mutex was locked when
it was destroyed.
MFC after: 3 days
kern_accept() and accept1(). If another thread closed the new file
descriptor and the first thread later got an error trying to copyout the
socket address, then it would attempt to close the wrong file object. To
fix, add a struct file ** argument to kern_accept(). If it is non-NULL,
then on success kern_accept() will store a pointer to the new file object
there and not release any of the references. It is up to the calling code
to drop the references appropriately (including a call to fdclose() in case
of error to safely handle the aforementioned race). While I'm at it, go
ahead and fix the svr4 streams code to not leak the accept fd if it gets an
error trying to copyout the streams structures.
have been invoked by uipc_close() or uipc_abort(), and the socket is in a
state of being torn down by the time we get to this point, so kqueue
state frobbed by soisdisconnected() is not available, so frobbing it will
result in a panic.
Reported by: Munehiro Matsuda <haro at h4 dot dion dot ne dot jp>
specific routines from uipc_socket2.c following repo-copy. We might
rethink the location of one or two at some point, but the division was
relatively clean. uipc_sockbuf.c is now the home of routines that
manipulate socket buffers.
soreceive(), and sopoll(), which are wrappers for pru_sosend,
pru_soreceive, and pru_sopoll, and are now used univerally by socket
consumers rather than either directly invoking the old so*() functions
or directly invoking the protocol switch method (about an even split
prior to this commit).
This completes an architectural change that was begun in 1996 to permit
protocols to provide substitute implementations, as now used by UDP.
Consumers now uniformly invoke sosend(), soreceive(), and sopoll() to
perform these operations on sockets -- in particular, distributed file
systems and socket system calls.
Architectural head nod: sam, gnn, wollman
the kernel malloc(9) state for vmstat -m. libmemstat is now used to
generate a machine-readable version which is converged by vmstat -m
into a human-readable version.
Not for MFC.
used to mark UNIX domain sockets as being in the process of binding or
connecting. Use these to prevent simultaneous bind or connect
operations by multiple threads or processes on the same socket at the
same time, which closes race conditions present in the UNIX domain
socket implementation since inception.
function, pru_close, to notify protocols that the file descriptor or
other consumer of a socket is closing the socket. pru_abort is now a
notification of close also, and no longer detaches. pru_detach is no
longer used to notify of close, and will be called during socket
tear-down by sofree() when all references to a socket evaporate after
an earlier call to abort or close the socket. This means detach is now
an unconditional teardown of a socket, whereas previously sockets could
persist after detach of the protocol retained a reference.
This faciliates sharing mutexes between layers of the network stack as
the mutex is required during the checking and removal of references at
the head of sofree(). With this change, pru_detach can now assume that
the mutex will no longer be required by the socket layer after
completion, whereas before this was not necessarily true.
Reviewed by: gnn
that the only remove hook operation that can occur while processing the
hooks is to remove the currently executing hook. This should be safe as
the existing code has assumed this already for a long time now.
Reviewed by: scottl
MFC after: 1 week
