simultaneous open. Both the bug and the patch were verified using the
ANVL test suite.
PR: kern/74935
Submitted by: qingli (before I became committer)
Reviewed by: andre
MFC after: 5 days
callout_drain() logic. We no longer need a separate non-spin mutex to
do sleep/wakeup with, instead we can now just use the one spin mutex to
manage all the callout functionality.
mutex.
- Don't use callout_drain() to stop the toffhandle callout while holding the
fdc mutex (this could deadlock) in functions called from softclock
(callouts aren't allowed to do voluntary sleeps). Instead, use
callout_stop(). Note that since we hold the associated mutex and are now
using callout_init_mtx(), callout_stop() is just as effective as
callout_drain(). (Though callout_drain() is still needed in detach to
make sure softclock isn't contesting on our mutex before we destroy the
mutex.)
- Remove unused callout 'tohandle' from softc.
MFC after: 1 week
the last reference is dropped. I forgot that vnodes can stick around
for a very long time until processes discover that they are dead. This
means that a vnode reference is not sufficient to keep the mount
referenced and even more code will be required to ref mount points.
Discovered by: kris
- Reorder the events in exit(2) slightly so that we trigger the S_EXIT
stop event earlier. After we have signalled that, we set P_WEXIT and
then wait for any processes with a hold on the vmspace via PHOLD to
release it. PHOLD now KASSERT()'s that P_WEXIT is clear when it is
invoked, and PRELE now does a wakeup if P_WEXIT is set and p_lock drops
to zero.
- Change proc_rwmem() to require that the processing read from has its
vmspace held via PHOLD by the caller and get rid of all the junk to
screw around with the vmspace reference count as we no longer need it.
- In ptrace() and pseudofs(), treat a process with P_WEXIT set as if it
doesn't exist.
- Only do one PHOLD in kern_ptrace() now, and do it earlier so it covers
FIX_SSTEP() (since on alpha at least this can end up calling proc_rwmem()
to clear an earlier single-step simualted via a breakpoint). We only
do one to avoid races. Also, by making the EINVAL error for unknown
requests be part of the default: case in the switch, the various
switch cases can now just break out to return which removes a _lot_ of
duplicated PRELE and proc unlocks, etc. Also, it fixes at least one bug
where a LWP ptrace command could return EINVAL with the proc lock still
held.
- Changed the locking for ptrace_single_step(), ptrace_set_pc(), and
ptrace_clear_single_step() to always be called with the proc lock
held (it was a mixed bag previously). Alpha and arm have to drop
the lock while the mess around with breakpoints, but other archs
avoid extra lock release/acquires in ptrace(). I did have to fix a
couple of other consumers in kern_kse and a few other places to
hold the proc lock and PHOLD.
Tested by: ps (1 mostly, but some bits of 2-4 as well)
MFC after: 1 week
interrupt handlers rather than BUS_SETUP_INTR() and BUS_TEARDOWN_INTR().
Uses of the BUS_*() versions in the implementation of foo_intr methods
in bus drivers were not changed. Mostly this just means that some
drivers might start printing diagnostic messages like [FAST] when
appropriate as well as honoring mpsafenet=0.
- Fix two more of the ppbus drivers' identify routines to function
correctly in the mythical case of a machine with more than one ppbus.
associated with the passed in pfs_node. If it does return a pointer, it
keeps the process locked. This allows a lot of places that were calling
pfind() again right after pfs_visible() to not have to do that and avoids
races since we don't drop the proc lock just to turn around and lock it
again. This will become more important with future changes to fix races
between procfs/ptrace and exit(2). Also, removed a duplicate pfs_visible()
call in pfs_getextattr().
Reviewed by: des
MFC after: 1 week
chdir(), be sure to undo the effects of the chdir before continuing.
Without this, after hitting a directory with mode 0111 (for example),
tar will get lost, and won't add any yet unvisted files to your
archive. (Or possibly add the wrong files, I suppose...)
Reviewed By: kientzle@
modules prior to looking up the directory which we will cover to avoid
this problem in mount.
- We must hold the coveredvp locked before we can busy the mountpoint to
prevent a lock order reversal with the vfs_busy() in lookup which holds
the directory lock prior to doing a vfs_busy(). The directory lock is
required to safely clear the v_mountedhere field on the directory.
MFC After: 1 week
prevent the mount point from going away while we're waiting on the lock.
The ref does not need to persist once we have the lock because the
lock prevents the mount point from being unmounted.
MFC After: 1 week
the VFS_STATFS call to prevent the mount from disappearing while we're
stating.
- Convert these routines to use MPSAFE namei semantics.
MFC After: 1 week
vop_lock_post do not trigger.
- Rearrange null_inactive to null_hashrem earlier so there is no chance
of finding the null node on the hash list after the locks have been
switched.
- We should never have a NULL lowervp in null_reclaim() so there is
no need to handle this situation. panic instead.
MFC After: 1 week
- Simplify the logic dealing with recycled vnodes in null_hashget() and
null_hashins(). Since we hold the lower node locked in both cases
the null node can not be undergoing recycling unless reclaim somehow
called null_nodeget(). The logic that was in place was not safe and
was essentially dead code.
MFC After: 1 week
