Preventing signal interrupt in Kernel module code

Preventing signal interrupt in Kernel module code

[Kevin Curtis]

Hi,
	I have written a Kernel module and I'm having a small problem with
signals that I hope someone can steer me through.  The signal in question
are SIGCHILD, but that is not really relevant.  I must be able to handle any
signal that the process has enabled.

	My module has several wait queues, most of which I can cope with
being interrupted by a signal (returning EINTR to the process).  However,
there are some hardware operations that I need to wait for completion of, as
it would be impossible to restart them or pick up where we left off.  I
still want to use a wait queue so other things can run.  Is there some
system call I can make to mask signals until the operation has completed.
Would I still call signal_pending() to see if one had occurred while they
were blocked?

I'm sure the answer is really simple but I haven't stumbled across it yet.

TIA

Kevin
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Preventing signal interrupt in Kernel module code

[Kevin Curtis]

Hi,
	I have written a Kernel module and I'm having a small problem with
signals that I hope someone can steer me through.  The signal in question
are SIGCHILD, but that is not really relevant.  I must be able to handle any
signal that the process has enabled.

	My module has several wait queues, most of which I can cope with
being interrupted by a signal (returning EINTR to the process).  However,
there are some hardware operations that I need to wait for completion of, as
it would be impossible to restart them or pick up where we left off.  I
still want to use a wait queue so other things can run.  Is there some
system call I can make to mask signals until the operation has completed.
Would I still call signal_pending() to see if one had occurred while they
were blocked?

I'm sure the answer is really simple but I haven't stumbled across it yet.

TIA

Kevin

RE: Preventing signal interrupt in Kernel module code

[Ken Boyer]

And I thought it was just me...

Are there any other Linux lists that are more of a beginner level? 

Ken


-----Original Message-----
From: linux-newbie-owner@vger.kernel.org
[mailto:linux-newbie-owner@vger.kernel.org] On Behalf Of Bill Pleasants
Sent: Friday, September 13, 2002 2:34 PM
To: linux-newbie@vger.kernel.org
Subject: Re: Preventing signal interrupt in Kernel module code


Hello,
I was told this list was for beginners.  From what I have read in the
past week, I think I am out of place.  I just want help getting a
Mandrake installation to work. Yours truly, Bill

        linux-newbie@vger.kernel.org, linux-kernel@vger.kernel.org
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Re: Preventing signal interrupt in Kernel module code

[Ray Olszewski]

At 11:33 AM 9/13/02 -0700, Bill Pleasants wrote:
>Hello,
>I was told this list was for beginners.  From what I have read in the
>past week, I think I am out of place.  I just want help getting a
>Mandrake installation to work.
>Yours truly,
>Bill


You were told right; this list is for beginners. Some of us who hang out 
here are not beginners, though (how else would you get knowledgeable 
*answers*, after all?), and one of us may, from time to time, pose a 
somewhat more advanced question to his colleagues. Not all that often, 
though ... there are better places to get answers to advanced questions 
than here.

That said, we don't have any automated filter to keep really complex 
questions off the list, and from time to time, someone will post an 
extremely technical question here. The one you posted in response to is a 
good example; I don't know if the poster will get any help here (he might, 
though it is a long shot), but his question really is way above what we 
customarily discuss.

That said ... we answer questions here. You don't ask any in your posting. 
If you are having trouble, you'll need to tell us what the trouble is.

Asking for help here is not a substitute for things like reading the 
documentation and following your distro's installations instructions -- we 
generally avoid the bluntness of "RTFM" and "STFW" replies, but we do 
retain the underlying expectation that for general questions, you will turn 
to FAQs, man pages, and other general documentation. If this is what you 
need to do, someone here will usually tell you so ... though a bit more 
politely than you might see elsewhere.

As to your questions ... we do assume that someone who wants help will make 
the effort to describe what he has done, and the problems he has 
encountered, with some specificity. We don't try to write personalized, 
soup-to-nuts tutorials.

So with that as background, please do not hesitate to pose beginner-level 
questions here.



--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski					-- Han Solo
Palo Alto, California, USA			  ray@comarre.com
-------------------------------------------------------------------------------

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Re: Preventing signal interrupt in Kernel module code

[Quinn Harris]

Would placing the process waiting for the hardware in an
TASK_UNINTERRUPTIBLE state do what you want?  As far as I understand
it,  the TASK_UNINTERRUPTIBLE state is used to prevent anything from
waking up a process when it is waiting for something it can't be
interrupted by a signal from.  If you call wait_event(wq, condition);
(actually a define in sched.h) the process will be placed in a
TASK_UNINTERRUPTIBLE state until the wait queue is woken up and the
condition is met.  wait_event_interruptible(wq, condition) would allow a
process to be interrupted by a signal.  You might be doing essentially
what wait_event does without using it.  I have seen a bit of kernel code
(I think usually older code) that doesn't used wait_event when it could
to place the current process on a wait queue.


On Fri, 2002-09-13 at 07:54, Kevin Curtis wrote:
> Hi,
> 	I have written a Kernel module and I'm having a small problem with
> signals that I hope someone can steer me through.  The signal in question
> are SIGCHILD, but that is not really relevant.  I must be able to handle any
> signal that the process has enabled.
> 
> 	My module has several wait queues, most of which I can cope with
> being interrupted by a signal (returning EINTR to the process).  However,
> there are some hardware operations that I need to wait for completion of, as
> it would be impossible to restart them or pick up where we left off.  I
> still want to use a wait queue so other things can run.  Is there some
> system call I can make to mask signals until the operation has completed.
> Would I still call signal_pending() to see if one had occurred while they
> were blocked?
> 
> I'm sure the answer is really simple but I haven't stumbled across it yet.
> 
> TIA
> 
> Kevin
> -
> To unsubscribe from this list: send the line "unsubscribe linux-newbie" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.linux-learn.org/faqs
> 


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RE: Preventing signal interrupt in Kernel module code

[Ken Boyer]

Thank you for the clarification.

Ken


-----Original Message-----
From: linux-newbie-owner@vger.kernel.org
[mailto:linux-newbie-owner@vger.kernel.org] On Behalf Of Ray Olszewski
Sent: Friday, September 13, 2002 11:54 AM
To: Bill Pleasants; linux-newbie@vger.kernel.org
Subject: Re: Preventing signal interrupt in Kernel module code


At 11:33 AM 9/13/02 -0700, Bill Pleasants wrote:
>Hello,
>I was told this list was for beginners.  From what I have read in the 
>past week, I think I am out of place.  I just want help getting a 
>Mandrake installation to work. Yours truly,
>Bill


You were told right; this list is for beginners. Some of us who hang out

here are not beginners, though (how else would you get knowledgeable 
*answers*, after all?), and one of us may, from time to time, pose a 
somewhat more advanced question to his colleagues. Not all that often, 
though ... there are better places to get answers to advanced questions 
than here.

That said, we don't have any automated filter to keep really complex 
questions off the list, and from time to time, someone will post an 
extremely technical question here. The one you posted in response to is
a 
good example; I don't know if the poster will get any help here (he
might, 
though it is a long shot), but his question really is way above what we 
customarily discuss.

That said ... we answer questions here. You don't ask any in your
posting. 
If you are having trouble, you'll need to tell us what the trouble is.

Asking for help here is not a substitute for things like reading the 
documentation and following your distro's installations instructions --
we 
generally avoid the bluntness of "RTFM" and "STFW" replies, but we do 
retain the underlying expectation that for general questions, you will
turn 
to FAQs, man pages, and other general documentation. If this is what you

need to do, someone here will usually tell you so ... though a bit more 
politely than you might see elsewhere.

As to your questions ... we do assume that someone who wants help will
make 
the effort to describe what he has done, and the problems he has 
encountered, with some specificity. We don't try to write personalized, 
soup-to-nuts tutorials.

So with that as background, please do not hesitate to pose
beginner-level 
questions here.



--
-------------------------------------------"Never tell me the
odds!"--------
Ray Olszewski					-- Han Solo
Palo Alto, California, USA			  ray@comarre.com
------------------------------------------------------------------------
-------

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Re: Preventing signal interrupt in Kernel module code

[Bill Pleasants]

Hello,
I was told this list was for beginners.  From what I have read in the
past week, I think I am out of place.  I just want help getting a
Mandrake installation to work.
Yours truly,
Bill

        linux-newbie@vger.kernel.org, linux-kernel@vger.kernel.org
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Re: starts error

[Ray Olszewski]

OK. I don't use Mandrake, so I can't help with Mandrake-specific bits like 
what an "automatic" installation of it does or what a Mandrake-specific doc 
says. Possibly someone else here is a Mandrake users with sufficient 
experience to help you at that level.

Since your problems are not Linux problems as such, but X problems, you 
need to look to the X sites for help. The core one is www.xfree86.org . I 
believe there are also X-related Linux HowTos; if they are not on your 
system somewhere (different distros handle them differently, and as I say, 
I am not familiar with the specifics of Mandrake), try www.linuxdoc.org .

As to your specific error -- execve is the C function (actually, one of 
several) called when one program executes another. Here, xinit is trying to 
start X (the actual server) and failing. The exact error values are hard 
for a beginner to track down -- they are buried in a set of header files, 
all called errno.h, in various locations within /usr/include/ -- but error 2 is

         #define ENOENT           2      /* No such file or directory */

Without more context, it is hard to know what this error means in your 
case. It may simply mean that the application /etc/X11/X (this is the 
actual X server) is missing from your system. That's trivially easy to 
check; just do "ls /etc/X11/X" to see if it is there. But I do not actually 
*know* that the error values that xinit is reporting are the standard errno 
numbers. So at this point, I'd look for an error in whatever file 
xf86config creates (perhaps /etc/X11/XF86Config-4 -- the exact path varies 
by distro, and the filename itself differs between X11 3.x.x and 4.x.x). 
I'd particularly inspect those "two suggested options" you added "manually" 
for errors.

As to your more general question (about info on commands), the first answer 
is to refer you to the FAQ listed at the end of list messages. Depending on 
what Mandrake has decided to install, you may have the man (online manual) 
system (start with "man man"), the info system ("info"), and/or a set of 
HowTos (look around; try in /usr/share/doc). Of these, the man system is 
closest to DOS's "help" system in style -- it is both a bit more cumbersome 
to read but also more helpful substantively (from my experience, at least 
... it's been a long time since I used DOS, though). Also, many commands 
will tell you something about themselves if you type the command name 
followed by either "-h" or "--help".

I'm sorry this is not a more direct answer, but I hope it give you some 
help nonetheless.

At 02:33 PM 9/13/02 -0700, Bill Pleasants wrote:
>Thanks for your kind welcome, Ray.  As for my specific question,
>I have not used Linux before. I erased Windows and did an automatic
>installation of Mandrake 7.2 on a Packard Bell A950-TWR with a P.B.
>monitor 1512SL . The X part failed and the computer boots to the
>command prompt. I tried the kde, gnome and startx commands without
>success. I followed the steps in mandrakeuser.org/docs/xwin/xtroub.html
>through running xf86config and manually adding two suggested options.
>
>After entering "startx" I get
>         "execve failed for /etc/X11/X (error 2)
>         giving up
>         xinit: Connection refused (error 111) unable to connect to X server
>         xinit: No such process (error 3): Server error."
>
>
>         Processor type: Intel pentium           Processor speed: 129.6
>         RAM: 16
>         HD type: ide                            HD capacity: 1.22
>         CD-ROM type: ide (judging by cable)
>         Graphic processor: Cirrus CL-GD5430/40  Video RAM: 1.024
>         Sound card: (with modem)
>
>Additional info that may be redundant:
>                             The video processor is on the main board. There
>                             is a chip labeled CIRRUS
>                             LOGIC CL-GD5430-QC-D. This is connected to
>                             a chip labeled VLSI 9531  D43851.
>
>                             The lspcidrake command gave:
>                             VLSI: 82C594-AFC2 (unknown ignore)
>                             VLSI 82C59617 [WILDCAT] (unknown ignore)
>                             CIRRUS LOGIC | GD 5430/40 [ALPINE]
>                             (DISPLAY_VGA CARD | CIRRUS LOGIC GD543X)
>                             CMD TECHNOLOGY INC. | PCI0640
>                             (STORAGE_IDE unknown)
>
>                             SuperProbe gave:
>                             SUPER-VGA
>                             CHIPS: CIRRUS CL-GD5430/40 (PCI PROBED)
>                             1,024 KB
>                             RAMDAC: CIRRUS LOGIC BUILT IN
>                             15/16/24-BIT DAC
>                             6 BIT LOOKUP TABLES
>
>I have spent at least 30 hours searching for interpretations of the
>error messages.  If this is available, I would appreciate knowing
>where.  I have seen other errors in various logs.  Also if there is a
>list of utilities on the machine and what they do like "help" on MS DOS,
>I would appreciate learning about it.





--
-------------------------------------------"Never tell me the odds!"--------
Ray Olszewski					-- Han Solo
Palo Alto, California, USA			  ray@comarre.com
-------------------------------------------------------------------------------

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Re: Preventing signal interrupt in Kernel module code

[Bryan Whitehead]

Bill Pleasants wrote:
> Hello,
> I was told this list was for beginners.  From what I have read in the
> past week, I think I am out of place.  I just want help getting a
> Mandrake installation to work.
> Yours truly,
> Bill
> 
>         linux-newbie@vger.kernel.org, linux-kernel@vger.kernel.org
> -
> To unsubscribe from this list: send the line "unsubscribe linux-newbie" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.linux-learn.org/faqs

Mandrake has a "newbie" list you might want to check out.

http://www.mandrakelinux.com/en/flists.php3

-- 
Bryan Whitehead
SysAdmin - JPL - Interferometry Systems and Technology
Phone: 818 354 2903
driver@jpl.nasa.gov

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starts error

[Bill Pleasants]

Thanks for your kind welcome, Ray.  As for my specific question,
I have not used Linux before. I erased Windows and did an automatic
installation of Mandrake 7.2 on a Packard Bell A950-TWR with a P.B.
monitor 1512SL . The X part failed and the computer boots to the 
command prompt. I tried the kde, gnome and startx commands without 
success. I followed the steps in mandrakeuser.org/docs/xwin/xtroub.html
through running xf86config and manually adding two suggested options.

After entering "startx" I get 
	"execve failed for /etc/X11/X (error 2)
	giving up
	xinit: Connection refused (error 111) unable to connect to X server
        xinit: No such process (error 3): Server error."


      	Processor type: Intel pentium 		Processor speed: 129.6
      	RAM: 16 					
	HD type: ide 				HD capacity: 1.22 
        CD-ROM type: ide (judging by cable)
        Graphic processor: Cirrus CL-GD5430/40 	Video RAM: 1.024
	Sound card: (with modem)	
                                                       
Additional info that may be redundant:
			    The video processor is on the main board. There
                            is a chip labeled CIRRUS 
                            LOGIC CL-GD5430-QC-D. This is connected to
                            a chip labeled VLSI 9531  D43851.

                            The lspcidrake command gave:
                            VLSI: 82C594-AFC2 (unknown ignore)
                            VLSI 82C59617 [WILDCAT] (unknown ignore)
                            CIRRUS LOGIC | GD 5430/40 [ALPINE]
                            (DISPLAY_VGA CARD | CIRRUS LOGIC GD543X)
                            CMD TECHNOLOGY INC. | PCI0640
                            (STORAGE_IDE unknown)

                            SuperProbe gave:
                            SUPER-VGA
                            CHIPS: CIRRUS CL-GD5430/40 (PCI PROBED)
                            1,024 KB
                            RAMDAC: CIRRUS LOGIC BUILT IN
                            15/16/24-BIT DAC
                            6 BIT LOOKUP TABLES

I have spent at least 30 hours searching for interpretations of the
error messages.  If this is available, I would appreciate knowing
where.  I have seen other errors in various logs.  Also if there is a
list of utilities on the machine and what they do like "help" on MS DOS,
I would appreciate learning about it.

Yours truly,
Bill
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Re: starts error

[pa3gcu]

On Friday 13 September 2002 21:33, Bill Pleasants wrote:
> Thanks for your kind welcome, Ray.  As for my specific question,
> I have not used Linux before. I erased Windows and did an automatic
> installation of Mandrake 7.2 on a Packard Bell A950-TWR with a P.B.
> monitor 1512SL . The X part failed and the computer boots to the
> command prompt. I tried the kde, gnome and startx commands without
> success. I followed the steps in mandrakeuser.org/docs/xwin/xtroub.html
> through running xf86config and manually adding two suggested options.

I wonder if you saw anymessage as to why it failed when the X part failed as 
you call it.?

>
> After entering "startx" I get
> 	"execve failed for /etc/X11/X (error 2)

As Ray pointed out error 2 = no such file or directory, the above path is not 
correct, mandrake has "X" (which is a symlink to Xwrapper) located in 
/usr/X11R6/bin/
So your installed scripts whichever one it is has a wrong path in it.

Now considering you say it all went wrong at install time here is what i 
would do;
Make sure X(programs) are installed, check out /usr/X11R6/bin it should have 
something like the following;

lrwxrwxrwx    1 root     root            8 Nov 17  2001 X -> Xwrapper*
-r-xr-xr-x    1 root     root      1838528 Nov 17  2001 XF86_VMware*
-rwxr-xr-x    1 root     root      1659708 Sep 22  2001 XFree86*
lrwxrwxrwx    1 root     root           15 Nov 17  2001 Xconfigurator -> 
../sbin/XFdrake
lrwxrwxrwx    1 root     root           19 Nov 17  2001 Xdrakres -> 
../..//sbin/XFdrake*
-rwxr-xr-x    1 root     root        27494 Sep 22  2001 Xmark*
-rwxr-xr-x    1 root     root      3091676 Sep 22  2001 Xprt*
-rws--x--x    1 root     root         6052 Sep 22  2001 Xwrapper*


Unfortunatly some lines are wrapped above so look carefully.
Now run Xconfigurator (if installed) and see what happens.


> 	giving up
> 	xinit: Connection refused (error 111) unable to connect to X server
>         xinit: No such process (error 3): Server error."
>
>
>       	Processor type: Intel pentium 		Processor speed: 129.6
>       	RAM: 16
> 	HD type: ide 				HD capacity: 1.22
>         CD-ROM type: ide (judging by cable)
>         Graphic processor: Cirrus CL-GD5430/40 	Video RAM: 1.024
> 	Sound card: (with modem)
>
> Additional info that may be redundant:
> 			    The video processor is on the main board. There
>                             is a chip labeled CIRRUS
>                             LOGIC CL-GD5430-QC-D. This is connected to
>                             a chip labeled VLSI 9531  D43851.
>
>                             The lspcidrake command gave:
>                             VLSI: 82C594-AFC2 (unknown ignore)
>                             VLSI 82C59617 [WILDCAT] (unknown ignore)
>                             CIRRUS LOGIC | GD 5430/40 [ALPINE]
>                             (DISPLAY_VGA CARD | CIRRUS LOGIC GD543X)
>                             CMD TECHNOLOGY INC. | PCI0640
>                             (STORAGE_IDE unknown)
>
>                             SuperProbe gave:
>                             SUPER-VGA
>                             CHIPS: CIRRUS CL-GD5430/40 (PCI PROBED)
>                             1,024 KB
>                             RAMDAC: CIRRUS LOGIC BUILT IN
>                             15/16/24-BIT DAC
>                             6 BIT LOOKUP TABLES
>
> I have spent at least 30 hours searching for interpretations of the
> error messages.  If this is available, I would appreciate knowing
> where.  I have seen other errors in various logs.  Also if there is a
> list of utilities on the machine and what they do like "help" on MS DOS,
> I would appreciate learning about it.

error numbers are defined in /usr/include/asm/errno.h
Ray explained the rest.

O yes your VGA card uses the cirrus driver but at the minute your problems 
start at an earlier stage, you are not getting as far as having X read its 
config file.

>
> Yours truly,
> Bill

-- 
Regards Richard
pa3gcu@zeelandnet.nl
http://people.zeelandnet.nl/pa3gcu/

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