callout is started before kern_setitimer() acquires process mutex, but
looses a race and kern_setitimer() gets the process mutex before the
callout. Then, assuming that new specified struct itimerval has
it_interval zero, but it_value non-zero, the callout, after it starts
executing again, clears p->p_realtimer.it_value, but kern_setitimer()
already rescheduled the callout.
As the result of the race, both p_realtimer is zero, and the callout
is rescheduled. Then, in the exit1(), the exit code sees that it_value
is zero and does not even try to stop the callout. This allows the
struct proc to be reused and eventually the armed callout is
re-initialized. The consequence is the corrupted callwheel tailq.
Use process mutex to interlock the callout start, which fixes the race.
Reported and tested by: pho
Reviewed by: jhb
MFC after: 2 weeks
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.
Reviewed by: rwatson
Approved by: re (bz)
rwlock to protect the table. In old code, thread lookup is done with
process lock held, to find a thread, kernel has to iterate through
process and thread list, this is quite inefficient.
With this change, test shows in extreme case performance is
dramatically improved.
Earlier patch was reviewed by: jhb, julian
the removal of NQNFS, but was left in in case it was required for NFSv4.
Since our new NFSv4 client and server can't use it for their
requirements, GC the old mechanism, as well as other unused lease-
related code and interfaces.
Due to its impact on kernel programming and binary interfaces, this
change should not be MFC'd.
Proposed by: jeff
Reviewed by: jeff
Discussed with: rmacklem, zach loafman @ isilon
Limit the size of malloced buffer when dumping environment
variables. [EN-09:01]
Approved by: so (cperciva)
Approved by: re (kensmith)
Security: FreeBSD-SA-09:06.ktimer
Errata: FreeBSD-EN-09:01.kenv
kern_time.c:
- Unused variable `p'.
kern_thr.c:
- Variable `error' is always caught immediately, so no reason to
initialize it. There is no way that error != 0 at the end of
create_thread().
kern_sig.c:
- Unused variable `code'.
kern_synch.c:
- `rval' is always assigned in all different cases.
kern_rwlock.c:
- `v' is always overwritten with RW_UNLOCKED further on.
kern_malloc.c:
- `size' is always initialized with the proper value before being used.
kern_exit.c:
- `error' is always caught and returned immediately. abort2() never
returns a non-zero value.
kern_exec.c:
- `len' is always assigned inside the if-statement right below it.
tty_info.c:
- `td' is always overwritten by FOREACH_THREAD_IN_PROC().
Found by: LLVM's scan-build
realtimer_expire() to not rearm the timer, otherwise there is a chance
that a callout will be left there and be tiggered in future unexpectly.
Bug reported by: tegge@
This patch fixes places where they should be called atomically changing
their locking requirements (both assume per-proc spinlock held) and
introducing rufetchcalc which wrappers both calls to be performed in
atomic way.
Reviewed by: jeff
Approved by: jeff (mentor)
- Use thread_lock() rather than sched_lock for per-thread scheduling
sychronization.
- Use the per-process spinlock rather than the sched_lock for per-process
scheduling synchronization.
Tested by: kris, current@
Tested on: i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
the introduction of priv(9) and MAC Framework entry points for privilege
checking/granting. These entry points exactly aligned with privileges and
provided no additional security context:
- mac_check_sysarch_ioperm()
- mac_check_kld_unload()
- mac_check_settime()
- mac_check_system_nfsd()
Add mpo_priv_check() implementations to Biba and LOMAC policies, which,
for each privilege, determine if they can be granted to processes
considered unprivileged by those two policies. These mostly, but not
entirely, align with the set of privileges granted in jails.
Obtained from: TrustedBSD Project
- Remove also "MP SAFE" after prior "MPSAFE" pass. (suggested by bde)
- Remove extra blank lines in some cases.
- Add extra blank lines in some cases.
- Remove no-op comments consisting solely of the function name, the word
"syscall", or the system call name.
- Add punctuation.
- Re-wrap some comments.
system calls now enter without Giant held, and then in some cases, acquire
Giant explicitly.
Remove a number of other MPSAFE annotations in the credential code and
tweak one or two other adjacent comments.
specific privilege names to a broad range of privileges. These may
require some future tweaking.
Sponsored by: nCircle Network Security, Inc.
Obtained from: TrustedBSD Project
Discussed on: arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
Alex Lyashkov <umka at sevcity dot net>,
Skip Ford <skip dot ford at verizon dot net>,
Antoine Brodin <antoine dot brodin at laposte dot net>
begun with a repo-copy of mac.h to mac_framework.h. sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.
This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.
Obtained from: TrustedBSD Project
Sponsored by: SPARTA
image_params arg.
- Change struct image_params to include struct sysentvec pointer and
initialize it.
- Change all consumers of process_exit/process_exec eventhandlers to
new prototypes (includes splitting up into distinct exec/exit functions).
- Add eventhandler to userret.
Sponsored by: Google SoC 2006
Submitted by: rdivacky
Parts suggested by: jhb (on hackers@)
application wishes to request high precision time stamps be returned:
Alias Existing
CLOCK_REALTIME_PRECISE CLOCK_REALTIME
CLOCK_MONOTONIC_PRECISE CLOCK_MONOTONIC
CLOCK_UPTIME_PRECISE CLOCK_UPTIME
Add experimental low-precision clockid_t names corresponding to these
clocks, but implemented using cached timestamps in kernel rather than
a full time counter query. This offers a minimum update rate of 1/HZ,
but in practice will often be more frequent due to the frequency of
time stamping in the kernel:
New clockid_t name Approximates existing clockid_t
CLOCK_REALTIME_FAST CLOCK_REALTIME
CLOCK_MONOTONIC_FAST CLOCK_MONOTONIC
CLOCK_UPTIME_FAST CLOCK_UPTIME
Add one additional new clockid_t, CLOCK_SECOND, which returns the
current second without performing a full time counter query or cache
lookup overhead to make sure the cached timestamp is stable. This is
intended to support very low granularity consumers, such as time(3).
The names, visibility, and implementation of the above are subject
to change, and will not be MFC'd any time soon. The goal is to
expose lower quality time measurement to applications willing to
sacrifice accuracy in performance critical paths, such as when taking
time stamps for the purpose of rescheduling select() and poll()
timeouts. Future changes might include retrofitting the time counter
infrastructure to allow the "fast" time query mechanisms to use a
different time counter, rather than a cached time counter (i.e.,
TSC).
NOTE: With different underlying time mechanisms exposed, using
different time query mechanisms in the same application may result in
relative non-monoticity or the appearance of clock stalling for a
single clockid_t, as a cached time stamp queried after a precision
time stamp lookup may be "before" the time returned by the earlier
live time counter query.
both proc pointer and thread pointer, if thread pointer is NULL,
tdsignal automatically finds a thread, otherwise it sends signal
to given thread.
Add utility function psignal_event to send a realtime sigevent
to a process according to the delivery requirement specified in
struct sigevent.
convert to or from timeval frequently.
Introduce function itimer_accept() to ack a timer signal in signal
acceptance code, this allows us to return more fresh overrun counter
than at signal generating time. while POSIX says:
"the value returned by timer_getoverrun() shall apply to the most
recent expiration signal delivery or acceptance for the timer,.."
I prefer returning it at acceptance time.
Introduce SIGEV_THREAD_ID notification mode, it is used by thread
libary to request kernel to deliver signal to a specified thread,
and in turn, the thread library may use the mechanism to implement
SIGEV_THREAD which is required by POSIX.
Timer signal is managed by timer code, so it can not fail even if
signal queue is full filled by sigqueue syscall.
clock are supported. I have plan to merge XSI timer ITIMER_REAL and other
two CPU timers into the new code, current three slots are available for
the XSI timers.
The SIGEV_THREAD notification type is not supported yet because our
sigevent struct lacks of two member fields:
sigev_notify_function
sigev_notify_attributes
I have found the sigevent is used in AIO, so I won't add the two members
unless the AIO code is adjusted.
pops data from the userland and pushes results back and the second which does
actual processing. Use the latter to eliminate stackgap in the linux wrappers
of those syscalls.
MFC after: 2 weeks
the raw values including for child process statistics and only compute the
system and user timevals on demand.
- Fix the various kern_wait() syscall wrappers to only pass in a rusage
pointer if they are going to use the result.
- Add a kern_getrusage() function for the ABI syscalls to use so that they
don't have to play stackgap games to call getrusage().
- Fix the svr4_sys_times() syscall to just call calcru() to calculate the
times it needs rather than calling getrusage() twice with associated
stackgap, etc.
- Add a new rusage_ext structure to store raw time stats such as tick counts
for user, system, and interrupt time as well as a bintime of the total
runtime. A new p_rux field in struct proc replaces the same inline fields
from struct proc (i.e. p_[isu]ticks, p_[isu]u, and p_runtime). A new p_crux
field in struct proc contains the "raw" child time usage statistics.
ruadd() has been changed to handle adding the associated rusage_ext
structures as well as the values in rusage. Effectively, the values in
rusage_ext replace the ru_utime and ru_stime values in struct rusage. These
two fields in struct rusage are no longer used in the kernel.
- calcru() has been split into a static worker function calcru1() that
calculates appropriate timevals for user and system time as well as updating
the rux_[isu]u fields of a passed in rusage_ext structure. calcru() uses a
copy of the process' p_rux structure to compute the timevals after updating
the runtime appropriately if any of the threads in that process are
currently executing. It also now only locks sched_lock internally while
doing the rux_runtime fixup. calcru() now only requires the caller to
hold the proc lock and calcru1() only requires the proc lock internally.
calcru() also no longer allows callers to ask for an interrupt timeval
since none of them actually did.
- calcru() now correctly handles threads executing on other CPUs.
- A new calccru() function computes the child system and user timevals by
calling calcru1() on p_crux. Note that this means that any code that wants
child times must now call this function rather than reading from p_cru
directly. This function also requires the proc lock.
- This finishes the locking for rusage and friends so some of the Giant locks
in exit1() and kern_wait() are now gone.
- The locking in ttyinfo() has been tweaked so that a shared lock of the
proctree lock is used to protect the process group rather than the process
group lock. By holding this lock until the end of the function we now
ensure that the process/thread that we pick to dump info about will no
longer vanish while we are trying to output its info to the console.
Submitted by: bde (mostly)
MFC after: 1 month
* Obtain/release schedlock around calls to calcru.
* Sort switch cases which do not cascade per style(9).
* Sort local variables per style(9).
* Remove "superfluous" whitespace.
* Cleanup handling of NULL uap->tp in clock_getres(). It would probably
be better to return EFAULT like clock_gettime() does by passing the
pointer to copyout(), but I presume it was written to not fail on
purpose in the original code. I'll defer to -standards on this one.
Reported by: bde
is currently executing when we try to remove it in exit1(). Without this,
it was possible for the callout to bogusly rearm itself and eventually
refire after the process had been free'd resulting in a panic.
PR: kern/51964
Reported by: Jilles Tjoelker <jilles@stack.nl>
Reviewed by: tegge, bde
