and there is no need to maintain it.
- Fix vn_get() in order to let it call vget(9) with a valid locking
request. vget(9) returns the vnode locked in order to prevent recycling,
but in this case internal XFS locks alredy prevent it from happening, so
it is safe to drop the vnode lock before to return by vn_get().
- Add a VNASSERT() in vget(9) in order to catch malformed locking requests.
Discussed with: kan, kib
Tested by: Lothar Braun <lothar at lobraun dot de>
interrupt-driven configuration handlers to complete, print out a
diagnostic message every 60 second indicating which handlers are
still running. Do this at most 5 times per run so as to avoid
scrolling out any useful information from the kernel message
buffer.
The interval of 60 seconds was selected based on a best guess as
to the nature of "long enough" and may want to be tuned higher
or lower depending on real-world tolerances.
MFC after: 3 days
Discussed with: scottl
for completion in run_interrupt_driven_config_hooks(). This is
helpful when trying to figure out which device drivers have gone
into la-la land during boot-time autoconfiguration.
MFC after: 3 days
- When a tick occurs on a cpu, iterate from cs_softticks until ticks.
The per-cpu tick processing happens asynchronously with the actual
adjustment of the 'ticks' variable. Sometimes the results may
be visible before the local call and sometimes after. Previously this
could cause a one tick window where we didn't evaluate the bucket.
- In softclock fetch curticks before incrementing cc_softticks so we
don't skip insertions which were made for the current time.
Sponsored by: Nokia
sched_tick() to prevent multiple increments for one tick. This pushes
the value out of range and breaks priority calculation.
Reviewed by: kib
Found by: pho/nokia
Sponsored by: Nokia
MFC after: 3 days
set MNT_UPDATE in fsflags, and delete the
"update" option from the global mount options.
MNT_UPDATE is a command, and not a property of a mount
that should persist after the command is executed.
We need to do similar things for MNT_FORCE and MNT_RELOAD.
All mount flags are prefixed by MNT_..... it would
be nice if flags which were commands were named differently
from flags which are persistent properties of a mount.
This was not such a big deal in the pre-nmount() days,
but with nmount() it is more important.
Requested by: yar
MFC after: 2 weeks
SI_ALIAS flag and initialization of the si_parent when alias is created.
Assert that supplied parent device is not NULL.
Both situations could cause NULL dereference in the
devfs_populate_loop() when creating a symlink for SI_ALIAS'ed device.
Namely, cdp->cdp_c.si_parent may be NULL.
Reported by: mav
MFC after: 2 weeks
the syscall code and acquires various event subsystem locks as needed.
The handling of the NOTE_TRACK for EVFILT_PROC is currently done by
calling the kqueue_register() from filt_proc() filter, causing recursive
entrance of the kqueue code. This results in the LORs and recursive
acquisition of the locks.
Implement the variant of the knote() function designed to only handle
the fork() event. It mostly copies the knote() body, but also handles
the NOTE_TRACK, removing the handling from the filt_proc(), where it
causes problems described above. The function is called from the fork1()
instead of knote().
When encountering NOTE_TRACK knote, it marks the knote as influx
and drops the knlist and kqueue lock. In this context call to
kqueue_register is safe from the problems.
An error from the kqueue_register() is reported to the observer as
NOTE_TRACKERR fflag.
PR: 108201
Reviewed by: jhb, Pramod Srinivasan <pramod juniper net> (previous version)
Discussed with: jmg
Tested by: pho
MFC after: 2 weeks
KQ_FLUX_WAKEUP(). Since the later macro clears the KQ_FLUXWAIT, the
kqueue_scan() thread may be not woken up.
Move the setting of KQ_FLUXWAIT after wakeup to correct the issue.
Reported and tested by: pho
MFC after: 3 days
to global hostname and domainname variables. Where necessary, copy
to or from a stack-local buffer before performing copyin() or
copyout(). A few uses, such as in cd9660 and daemon_saver, remain
under-synchronized and will require further updates.
Correct a bug in which a failed copyin() of domainname would leave
domainname potentially corrupted.
MFC after: 3 weeks
dispatched without Giant, and add NETISR_FORCEQUEUE, which allows specific
netisr handlers to always be dispatched via a queue (deferred). Mark the
usb and if_ppp netisr handlers as NETISR_FORCEQUEUE, and explicitly
acquire Giant in those handlers.
Previously, any netisr handler not marked NETISR_MPSAFE would necessarily
run deferred and with Giant acquired. This change removes Giant
scaffolding from the netisr infrastructure, but NETISR_FORCEQUEUE allows
non-MPSAFE handlers to continue to force deferred dispatch so as to avoid
lock order reversals between their acqusition of Giant and any calling
context.
It is likely we will be able to remove NETISR_FORCEQUEUE once
IFF_NEEDSGIANT is removed, as non-MPSAFE usb and if_ppp drivers will no
longer be supported.
Reviewed by: bz
MFC after: 1 month
X-MFC note: We can't remove NETISR_MPSAFE from stable/7 for KPI reasons,
but the rest can go back.
soun->sun_path isn't a null-terminated string. As UNIX(4) states, "the
terminating NUL is not part of the address." Since strlcpy has to return
"the total length of the string [it] tried to create," it walks off the end
of soun->sun_path looking for a \0.
This reverts r105332.
Reported by: Ryan Stone
datagram-only protocols, such as UDP. This version removes use of
sblock(), which is not required due to an inability to interlace data
improperly with datagrams, as well as avoiding some of the larger loops
and state management that don't apply on datagram sockets.
This is experimental code, so hook it up only for UDPv4 for testing; if
there are problems we may need to revise it or turn it off by default,
but it offers *significant* performance improvements for threaded UDP
applications such as BIND9, nsd, and memcached using UDP.
Tested by: kris, ps
already commited but with a wrong msleep variant and then
backed out. Note that this changes the semantic a little
as msleep_spin does not let us to specify priority after
wakeup.
Approved by: wkoszek, cognet
Approved by: kib (mentor)
semaphores. Specifically, semaphores are now represented as new file
descriptor type that is set to close on exec. This removes the need for
all of the manual process reference counting (and fork, exec, and exit
event handlers) as the normal file descriptor operations handle all of
that for us nicely. It is also suggested as one possible implementation
in the spec and at least one other OS (OS X) uses this approach.
Some bugs that were fixed as a result include:
- References to a named semaphore whose name is removed still work after
the sem_unlink() operation. Prior to this patch, if a semaphore's name
was removed, valid handles from sem_open() would get EINVAL errors from
sem_getvalue(), sem_post(), etc. This fixes that.
- Unnamed semaphores created with sem_init() were not cleaned up when a
process exited or exec'd. They were only cleaned up if the process
did an explicit sem_destroy(). This could result in a leak of semaphore
objects that could never be cleaned up.
- On the other hand, if another process guessed the id (kernel pointer to
'struct ksem' of an unnamed semaphore (created via sem_init)) and had
write access to the semaphore based on UID/GID checks, then that other
process could manipulate the semaphore via sem_destroy(), sem_post(),
sem_wait(), etc.
- As part of the permission check (UID/GID), the umask of the proces
creating the semaphore was not honored. Thus if your umask denied group
read/write access but the explicit mode in the sem_init() call allowed
it, the semaphore would be readable/writable by other users in the
same group, for example. This includes access via the previous bug.
- If the module refused to unload because there were active semaphores,
then it might have deregistered one or more of the semaphore system
calls before it noticed that there was a problem. I'm not sure if
this actually happened as the order that modules are discovered by the
kernel linker depends on how the actual .ko file is linked. One can
make the order deterministic by using a single module with a mod_event
handler that explicitly registers syscalls (and deregisters during
unload after any checks). This also fixes a race where even if the
sem_module unloaded first it would have destroyed locks that the
syscalls might be trying to access if they are still executing when
they are unloaded.
XXX: By the way, deregistering system calls doesn't do any blocking
to drain any threads from the calls.
- Some minor fixes to errno values on error. For example, sem_init()
isn't documented to return ENFILE or EMFILE if we run out of semaphores
the way that sem_open() can. Instead, it should return ENOSPC in that
case.
Other changes:
- Kernel semaphores now use a hash table to manage the namespace of
named semaphores nearly in a similar fashion to the POSIX shared memory
object file descriptors. Kernel semaphores can now also have names
longer than 14 chars (up to MAXPATHLEN) and can include subdirectories
in their pathname.
- The UID/GID permission checks for access to a named semaphore are now
done via vaccess() rather than a home-rolled set of checks.
- Now that kernel semaphores have an associated file object, the various
MAC checks for POSIX semaphores accept both a file credential and an
active credential. There is also a new posixsem_check_stat() since it
is possible to fstat() a semaphore file descriptor.
- A small set of regression tests (using the ksem API directly) is present
in src/tools/regression/posixsem.
Reported by: kris (1)
Tested by: kris
Reviewed by: rwatson (lightly)
MFC after: 1 month
provides the correct semantics for flock(2) style locks which are used by the
lockf(1) command line tool and the pidfile(3) library. It also implements
recovery from server restarts and ensures that dirty cache blocks are written
to the server before obtaining locks (allowing multiple clients to use file
locking to safely share data).
Sponsored by: Isilon Systems
PR: 94256
MFC after: 2 weeks
so we cannot compile it with -fstack-protector[-all] flags (or
it will self-recurse); this is ensured in sys/conf/files. This
OTOH means that checking for defines __SSP__ and __SSP_ALL__ to
determine if we should be compiling the support is impossible
(which it was trying, resulting in an empty object file). Fix
this by always compiling the symbols in this files. It's good
because it allows us to always have SSP support, and then compile
with SSP selectively.
Repoted by: tinderbox
- It is opt-out for now so as to give it maximum testing, but it may be
turned opt-in for stable branches depending on the consensus. You
can turn it off with WITHOUT_SSP.
- WITHOUT_SSP was previously used to disable the build of GNU libssp.
It is harmless to steal the knob as SSP symbols have been provided
by libc for a long time, GNU libssp should not have been much used.
- SSP is disabled in a few corners such as system bootstrap programs
(sys/boot), process bootstrap code (rtld, csu) and SSP symbols themselves.
- It should be safe to use -fstack-protector-all to build world, however
libc will be automatically downgraded to -fstack-protector because it
breaks rtld otherwise.
- This option is unavailable on ia64.
Enable GCC stack protection (aka Propolice) for kernel:
- It is opt-out for now so as to give it maximum testing.
- Do not compile your kernel with -fstack-protector-all, it won't work.
Submitted by: Jeremie Le Hen <jeremie@le-hen.org>
locked and unlocked completely in userland. by locking and unlocking mutex
in userland, it reduces the total time a mutex is locked by a thread,
in some application code, a mutex only protects a small piece of code, the
code's execution time is less than a simple system call, if a lock contention
happens, however in current implemenation, the lock holder has to extend its
locking time and enter kernel to unlock it, the change avoids this disadvantage,
it first sets mutex to free state and then enters kernel and wake one waiter
up. This improves performance dramatically in some sysbench mutex tests.
Tested by: kris
Sounds great: jeff
FIFO, as required by SUSv3. No specific privilege check is performed
in this case, as FIFOs may be created by unprivileged processes
(subject to the normal file system name space restrictions that may be
in place).
Unlike the Apple implementation, we reject requests to create a FIFO
using mknod(2) if there is a non-zero dev argument to the system call,
which is permitted by the Open Group specification ("... undefined
..."). We might want to revise this if we find it causes
compatibility problems for applications in practice.
PR: kern/74242, kern/68459
Obtained from: Apple, Inc.
MFC after: 3 weeks
