- document a data structure invariant in lockf.h
- add KASSERT() to check the invariant.
- be more consistent about dequeuing ourselves from the blocked list
after a tsleep().
- Fix two places where the invariant is violated.
- correct a few comments here and there
- If we're still following a lock dependancy chain after maxlockdepth
processes and haven't gotten back to the start, assume that we're in a
cycle anyway and return EDEADLK.
Fix is a superset of an existing fix in FreeBSD, but independantly
derived.
Fixes kern/3860.
- add a new global variable, doing_shutdown, which is nonzero if
vfs_shutdown() or panic() have been called.
- in panic, set RB_NOSYNC if doing_shutdown is already set on entry
so we don't reenter vfs_shutdown if we panic'ed there.
- in vfs_shutdown, don't use proc0's process for sys_sync unless
curproc is NULL.
- in lockmgr, attribute successful locks to proc0 if doing_shutdown
&& curproc==NULL, and panic if we can't get the lock right away; avoids the
spurious lockmgr DIAGNOSTIC panic from the ddb reboot command.
- in subr_pool, deal with curproc==NULL in the doing_shutdown case.
- in mfs_strategy, bitbucket writes if doing_shutdown, so we don't
wedge waiting for the mfs process.
- in ltsleep, treat ((curproc == NULL) && doing_shutdown) like the
panicstr case.
Appears to fix: kern/9239, kern/10187, kern/9367.
May also fix kern/10122.
interlock is released once the scheduler is locked, so that a race
between a sleeper and an awakener is prevented in a multiprocessor
environment. Provide a tsleep() macro that provides the old API.
on LP64 systems (and probably the SPARC) since the __cmsg_alignbytes()
changes went in.
- Change file descriptor passing to use CMSG_DATA(), not (cm + 1). This
pretty much has to be done in order to make it work properly on LP64,
and considering that it's been broken this long...
- Use CMSG_SPACE() to determine the mbuf length needed for a given
control message, and CMSG_LEN() to stash in the cmsg_len member.
"KERN_SYSVIPC_SEM_INFO" and "KERN_SYSVIPC_SHM_INFO" to return the
info and data structures for the relevent SysV IPC types. The return
structures use fixed-size types and should be compat32 safe. All
user-visible changes are protected with
#if !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE)
Make all variable declarations extern in msg.h, sem.h and shm.h and
add relevent variable declarations to sysv_*.c and remove unneeded
header files from those .c files.
Make compat14 SysV IPC conversion functions and sysctl_file() static.
Change the data pointer to "void *" in sysctl_clockrate(),
sysctl_ntptime(), sysctl_file() and sysctl_doeproc().
p_cpu member to struct proc. Use this in certain places when
accessing scheduler state, etc. For the single-processor case,
just initialize p_cpu in fork1() to avoid having to set it in the
low-level context switch code on platforms which will never have
multiprocessing.
While I'm here, comment a few places where there are known issues
for the SMP implementation.
- need deep compare of open files, not a shallow pointer compare.
- reorder fdrelease()/FILE_UNUSE() invocations so fdrelease doesn't
block waiting for something which can't happen until after it returns.
doing a cpu_set_kpc(), just pass the entry point and argument all
the way down the fork path starting with fork1(). In order to
avoid special-casing the normal fork in every cpu_fork(), MI code
passes down child_return() and the child process pointer explicitly.
This fixes a race condition on multiprocessor systems; a CPU could
grab the newly created processes (which has been placed on a run queue)
before cpu_set_kpc() would be performed.
sys_semconfig into a placebo system call, to avoid giving folks an
easy way to wedge processes which use semaphores.
NOTE: unlike 386bsd and freebsd, processes which did not have
semaphore undo records would not be affected by this problem (reducing
it from a serious local denial-of-service problem to a largely
cosmetic problem, since virtually nobody uses semaphores). But the
code is just Wrong so we're ripping it out anyway.
by Anders Magnusson.
Honor elem_count in the KERN_PROC2 case, as well as overall buffer
space. The only user-land code to use this set the elem_count to
"buffer_space / elem_size", so we've had no incorrect behaviour to date.
- Change ktrace interface to pass in the current process, rather than
p->p_tracep, since the various ktr* function need curproc anyway.
- Add curproc as a parameter to mi_switch() since all callers had it
handy anyway.
- Add a second proc argument for inferior() since callers all had
curproc handy.
Also, miscellaneous cleanups in ktrace:
- ktrace now always uses file-based, rather than vnode-based I/O
(simplifies, increases type safety); eliminate KTRFLAG_FD & KTRFAC_FD.
Do non-blocking I/O, and yield a finite number of times when receiving
EWOULDBLOCK before giving up.
- move code duplicated between sys_fktrace and sys_ktrace into ktrace_common.
- simplify interface to ktrwrite()
state into global and per-CPU scheduler state:
- Global state: sched_qs (run queues), sched_whichqs (bitmap
of non-empty run queues), sched_slpque (sleep queues).
NOTE: These may collectively move into a struct schedstate
at some point in the future.
- Per-CPU state, struct schedstate_percpu: spc_runtime
(time process on this CPU started running), spc_flags
(replaces struct proc's p_schedflags), and
spc_curpriority (usrpri of processes on this CPU).
- Every platform must now supply a struct cpu_info and
a curcpu() macro. Simplify existing cpu_info declarations
where appropriate.
- All references to per-CPU scheduler state now made through
curcpu(). NOTE: this will likely be adjusted in the future
after further changes to struct proc are made.
Tested on i386 and Alpha. Changes are mostly mechanical, but apologies
in advance if it doesn't compile on a particular platform.
db_stack_trace_print(__builtin_frame_address(0),...), to printf() the
stack trace to the message bufffer and console. Idea from SunOS/Solaris.
Useful when dumping fails.
errors from ps(1) and some other kernel grovellers, and return some
data that has previously only been accessable with /dev/kmem read
access. The sysctls are:
+ KERN_PROC2 - return an array of fixed sized "struct kinfo_proc2"
structures that contain most of the useful user-level data in
"struct proc" and "struct user". The sysctl also takes the size of
each element, so that if "struct kinfo_proc2" grows over time old
binaries will still be able to request a fixed size amount of data.
+ KERN_PROC_ARGS - return the argv or envv for a particular process id.
envv will only be returned if the process has the same user id as the
requestor or if the requestor is root.
+ KERN_FSCALE - return the current kernel fixpt scale factor.
+ KERN_CCPU - return the scheduler exponential decay value.
+ KERN_CP_TIME - return cpu time state counters.
With input and suggestions from many people on tech-kern.
