Node.js Version:6.9
OS:linux
Scope (install, code, runtime, meta, other?):
Module (and version) (if relevant):
Project Adress: https://github.com/dreamyzhang/nodectp
Question 1:
It would be coredump when run some time. as follows:
node: src/threadpool.c:252: uv__queue_done: Assertion `(((const QUEUE *) (&(req->loop)->active_reqs) == (const QUEUE ) ((QUEUE **) &((*(&(req->loop)->active_reqs))[0]))) == 0)' failed.
Question 2:
the same node version 6.9. when installed by nvm will coredump like #485.
I'm posting my comment here as an answer:
You are using uv_queue_work from a thread which is not the loop thread. This is not supported behavior (the loop API is not thread-safe unless stated otherwise, which is not the case).
The threading model is defined here.
Related
I'm attempting to make a Lisp package with uiop/package:define-package. I'm using SBCL, and have confirmed that package-local nicknaming ought to be supported:
* *features*
(:QUICKLISP :ASDF3.3 :ASDF3.2 :ASDF3.1 :ASDF3 :ASDF2 :ASDF :OS-UNIX
:NON-BASE-CHARS-EXIST-P :ASDF-UNICODE :X86-64 :GENCGC :64-BIT :ANSI-CL
:COMMON-LISP :ELF :IEEE-FLOATING-POINT :LINUX :LITTLE-ENDIAN
:PACKAGE-LOCAL-NICKNAMES :SB-CORE-COMPRESSION :SB-LDB :SB-PACKAGE-LOCKS
:SB-THREAD :SB-UNICODE :SBCL :UNIX)
* (uiop:featurep :package-local-nicknames)
T
Nevertheless, when I try to define a package that has local nicknames, it doesn't work:
(uiop/package:define-package #:foo
(:use #:cl)
(:local-nicknames (#:b #:binparse)))
debugger invoked on a SIMPLE-ERROR in thread
#<THREAD "main thread" RUNNING {1001878103}>:
unrecognized define-package keyword :LOCAL-NICKNAMES
Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.
restarts (invokable by number or by possibly-abbreviated name):
0: [ABORT] Exit debugger, returning to top level.
(UIOP/PACKAGE:PARSE-DEFINE-PACKAGE-FORM #:FOO ((:USE #:CL) (:LOCAL-NICKNAMES (#:B #:BINPARSE))))
source: (ERROR "unrecognized define-package keyword ~S" KW)
0] 0
(binparse being another package I've made, which worked fine, but which did not happen to use local nicknaming).
What I've found of the uiop/package source seems to indicate that this shouldn't happen? Going by that, it should either work, or have a specific error message indicating the non-supported-ness of local nicknames (if somehow uiop:featurep is inaccurate or changing), but it shouldn't give a generic unknown-keyword error. At this point I'm not sure what I could be getting wrong.
The version of asdf that's included in releases of sbcl is based on asdf version 3.3.1 (November 2017), except bundled into only two (larger) lisp files (one for asdf and one for uiop) rather than breaking them up by purpose as is done in official releases of asdf. asdf added #+sbcl support for package-local nicknames in 3.3.3.2 (August 2019), and switched to the more general #+package-local-nicknames in 3.3.4.1 (April 2020) (the latest release version is 3.3.4, though, so that wouldn't be in yet anyway). So it's "just" a delay in pulling from upstream. Following the instructions on upgrading ASDF did the trick – extract the latest release tarball into ~/common-lisp/asdf and run (load (compile-file #P"~/common-lisp/asdf/build/asdf.lisp")) once, and future shells will use the updated version.
Goal: allow c extension to receive block/proc for delayed execution while retaining current execution context.
I have a method in c (exposed to ruby) that accepts a callback (via VALUE hash argument) or a block.
// For brevity, lets assume m_CBYO is setup to make a CBYO module available to ruby
extern VALUE m_CBYO;
VALUE CBYO_add_callback(VALUE callback)
{
if (rb_block_given_p()) {
callback = rb_block_proc();
}
if (NIL_P(callback)) {
rb_raise(rb_eArgError, "either a block or callback proc is required");
}
// method is called here to add the callback proc to rb_callbacks
}
rb_define_module_function(m_CBYO, "add_callback", CBYO_add_callback, 1);
I have a struct I'm using to store these with some extra data:
struct rb_callback
{
VALUE rb_cb;
unsigned long long lastcall;
struct rb_callback *next;
};
static struct rb_callback *rb_callbacks = NULL;
When it comes time (triggered by an epoll), I iterate over the callbacks and execute each callback:
rb_funcall(cb->rb_cb, rb_intern("call"), 0);
When this happens I am seeing that it successfully executes the ruby code in the callback, however, it is escaping the current execution context.
Example:
# From ruby including the above extension
CBYO.add_callback do
puts "Hey now."
end
loop do
puts "Waiting for signal..."
sleep 1
end
When a signal is received (via epoll) I will see the following:
$> Waiting for signal...
$> Waiting for signal...
$> Hey now.
$> // process hangs
$> // Another signal occurs
$> [BUG] vm_call_cfunc - cfp consistency error
Sometimes, I can get more than one signal to process before the bug surfaces again.
I found the answer while investigating a similar issue.
As it turns out, I too was trying to use native thread signals (with pthread_create) which are not supported with MRI.
TLDR; the Ruby VM is not currently (at the time of writing) thread safe. Check out this nice write-up on Ruby Threading for a better overall understanding of how to work within these confines.
You can use Ruby's native_thread_create(rb_thread_t *th) which will use pthread_create behind the scenes. There are some drawbacks that you can read about in the documentation above the method definition. You can then run the callback with Ruby's rb_thread_call_with_gvl method. Also, I haven't done it here, but it might be a good idea to create a wrapper method so you can use rb_protect to handle exceptions the callback may raise (otherwise they will be swallowed by the VM).
VALUE execute_callback(VALUE callback)
{
return rb_funcall(callback, rb_intern("call"), 0);
}
// execute the callback when the thread receives signal
rb_thread_call_with_gvl(execute_callback, data->callback);
Recently I have been working with frama-c and I have faced a problem which is a bit confusing.
I have written a very simple program in frama-c which is this:
void main(void)
{
int a = 3;
int b = 4;
/*# assert a == b;*/
}
I expect frama-c to say the assertion is not valid which in GUI this is shown by red bullet, but instead frama-c says the assertion is not valid according to value (under hypothesis), which is shown by orange-red bullet.
My question is why would frama-c say the assertion is not valid under hypothesis?
What are the possible hypotheses?
I am asking this because my program is very simple and I can't find any hypothesis or dependency in my program which is related to the assertion and I guess frama-c should just say the assertion is not valid.
If you have graphviz configured with your Frama-C installation (i.e. it was available when Frama-C was configured, either manually or via opam), you can double-click the property in the Properties panel, and a window should open with the following dependency graph for the property:
In it, we can see all the hypotheses used by a property, and so we see that the "under hypotheses" mentioned is that of the reachability of the assertion. Eva (value plug-in) computes an over-approximation of reachable states, so it cannot prove that a given state is reachable, only that it is unreachable.
Currently, the only plug-in which can definitely prove reachability statuses is PathCrawler. However, in practice this is rarely an issue.
An alternative way to see the dependencies of a property proven under hypotheses is to use the Report plugin, on the command-line:
$ frama-c -val c.c -then -report
[report] Computing properties status...
--------------------------------------------------------------------------------
--- Properties of Function 'main'
--------------------------------------------------------------------------------
[ Alarm ] Assertion (file c.c, line 5)
By Value, with pending:
- Unreachable program point (file c.c, line 5)
--------------------------------------------------------------------------------
--- Status Report Summary
--------------------------------------------------------------------------------
1 Alarm emitted
1 Total
--------------------------------------------------------------------------------
The pending information lists all the properties required to finish the proof. For statutes emitted by the Value/Eva plugin, the only dependences emitted will always be reachability ones.
(This is actually misleading: the status of the n th property actually depends on the statuses for the properties k with k < n. This would generate a dependency graph too big, so those dependencies are not tracked.)
if((sem_init(sem, 1, 1)) == 1) perror("error initiating sem");
If I include this line of code my program simply starts and exits. I just started learning how to use semaphores. I'm using cygwin and when this line is commented out the printf's ABOVE this print to console but when include this, nothing happens.
I did the following to get cygserver going-
CYGWIN=server
ran /bin/cygserver-config
ran /usr/sbin/cygserver
for the config it said the cygserver is already running
And for the sygserver it saids-
initailaizing complete
failed to created named pipe: is the daemon already running?
fatal error on IPC transport: closing down
Any ideas?
I figured out what was wrong. I was using data(struct) = shmat() before I was assigning any memory to data. That for some reason was stopping my 'printf' from working.
I am trying to write an interface between RSPEC (ruby flavoured BDD) and a Windows application. The application itself is written in an obscure language, but it has a C API to provide access. I've gone with Ruby/DL but am having difficulties getting even the most basic call to a DLL method to work. Here is what I have so far, in a file called gt4r.rb:
require 'dl/import'
module Gt4r
extend DL::Importable
dlload 'c:\\gtdev\\r321\\bin\\gtvapi'
# GTD initialization/termination functions
extern 'int GTD_init(char *[], char *, char *)'
extern 'int GTD_initialize(char *, char *, char *)'
extern 'int GTD_done(void)'
extern 'int GTD_get_error_message(int, char **)'
end
My reading so far suggests that this is all I need to get going, so I wrote up a RSPEC example:
require 'gt4r'
##test_environment = "INCLUDE=C:\\graphtalk\\env\\aiadev\\config\\aiadev.ini"
##normal_user = "BMCHARGUE"
describe Gt4r do
it 'initializes' do
rv = Gt4r.gTD_initialize ##normal_user, ##normal_user, ##test_environment
rv.should == 0
end
end
And when run...
C:\code\GraphTalk>spec -fs -rgt4r gt4r_spec.rb
Gt4r
- initializes (FAILED - 1)
1)
'Gt4r initializes' FAILED
expected: 0,
got: 13 (using ==)
./gt4r_spec.rb:9:
Finished in 0.031 seconds
1 example, 1 failure
The return value (13) is an actual return code, meaning an error, but when I try to add the gTD_get_error_message call to my RSPEC, I can't get the parameters to work.
Am I heading in the right direction and can anyone point to the next thing I can try?
Thanks,
Brett
A follow up to this question, showing the part that fails when I try to get the error message from my target library:
require 'gt4r'
##test_environment = "INCLUDE=C:\\graphtalk\\env\\aiadev\\config\\aiadev.ini"
##normal_user = "BMCHARGUE"
describe Gt4r do
it 'initializes' do
rv = Gt4r.gTD_initialize ##normal_user, ##normal_user, ##test_environment
Gt4r.gTD_get_error_message rv, #msg
#msg.should == ""
rv.should == 0
end
end
I expect the error message to be returned in #msg, but when run I get the following:
Gt4r
(eval):5: [BUG] Segmentation fault
ruby 1.8.6 (2008-08-11) [i386-mswin32]
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
And this if I use a symbol (:msg) instead:
C:\code\GraphTalk\gt4r_dl>spec -fs -rgt4r gt4r_spec.rb
Gt4r
- initializes (ERROR - 1)
1)
NoMethodError in 'Gt4r initializes'
undefined method `to_ptr' for :msg:Symbol
(eval):5:in `call'
(eval):5:in `gTD_get_error_message'
./gt4r_spec.rb:9:
Finished in 0.046 seconds
1 example, 1 failure
Clearly I am missing something about passing parameters between ruby and C, but what?
The general consensus is you want to avoid DL as much as possible. The (english) documentation is quite sketchy and the interface is difficult to use for anything but trivial examples.
Ruby native C interface is MUCH easier to program against. Or you could use FFI, which fills a similiar niche to DL, originally comes from the rubinius project and has recently been ported to "normal" ruby. It has a nicer interface and is much less painful to use:
http://blog.headius.com/2008/10/ffi-for-ruby-now-available.html
The return value (13) is an actual
return code, meaning an error, but
when I try to add the
gTD_get_error_message call to my
RSPEC, I can't get the parameters to
work.
It might help posting the error instead of the code that worked :)
Basically, once you start having to deal with pointers as in (int, char **), things get ugly.
You need to allocate the data pointer for msg to be written to, since otherise C will have nowhere to write the error messages. Use DL.mallo.