August 2010 - Darwin-kernel

Re: close() hangs when closing a kqueue in 10.5 only
by Jerry Krinock 16 Aug '10

16 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On 2010 Aug 16, at 11:48, Graham Lee wrote: > On 16 Aug 2010, at 19:41, Jerry Krinock wrote: > >> Is close() open-source? I can't find it in macosforge.org or opensource.apple.com. > > Look in libsystem (where the close() library function is defined), and xnu (where the system call is implemented). Thank you, Graham. But I've been clicking and clacking for 10 minutes but still can't find the source code for close() in libsystem or xnu. If anyone could take my hand for the first couple steps in finding this I'd appreciate it. Jerry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: close() hangs when closing a kqueue in 10.5 only
by Graham Lee 16 Aug '10

16 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha1; c=relaxed; d=thaesofereode.info; h= subject:mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; s= thaesofereode.info; bh=xmXE3cJBqs9HBndD4+EX3Kf+9zs=; b=A8CAP64bz z9WQM0tGWLP432hFiRi/pIPG+n9GTBG2aHY8X3ACmeAMcWzh37lhA+XejnBygwJS nQh7ibNaCPWqKMvQ+SvclzYc7g93jT/Wy3HnNxi1vb8E7Ea0079iJpLGUPXb88v2 7mIDONmdPKI2QjLuUWDSsvUzh88h5m2G9U= Domainkey-signature: a=rsa-sha1; c=nofws; d=thaesofereode.info; h=subject :mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; q=dns; s= thaesofereode.info; b=WvUivvCcXJr8B2W/S3l3K76YcNn8fEV0ljeHCull7y U46iV++iPu9apFPMrJxGehlmSYI/O8igEmgqsAoR+bDChg645llNiH/yPIdhMh11 yhCG/qjwqW8wwdWwNldkaaEia/cut7NrDUzrahwYtQaAQXBmx4id+xQzhXsLsM3h A= On 16 Aug 2010, at 19:41, Jerry Krinock wrote: > Is close() open-source? I can't find it in macosforge.org or opensource.apple.com. Look in libsystem (where the close() library function is defined), and xnu (where the system call is implemented). Graham. -- Graham Lee http://blog.securemacprogramming.com/ http://www.mac-developer-network.com/articles/scindex.html _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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close() hangs when closing a kqueue in 10.5 only
by Jerry Krinock 16 Aug '10

16 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com A Cocoa app I've written uses a kqueue to watch its document file. It works fine in Mac OS 10.6, but when run in Mac OS 10.5.8, when I close the kqueue like this: close (kqueueFileDescriptor) ; The function close() hangs forever. The argument kqueueFileDescriptor is the integer I got previously from: NSInteger kqueueFileDescriptor = kqueue() ; Does anyone know what might be going on here? Documentation says that read() can block until data is ready, but there is no mention of this in the documentation for close(). I suppose I could just leave the kqueue open if running in 10.5, because a typical application run only creates one of them. Is close() open-source? I can't find it in macosforge.org or opensource.apple.com. Thank you, Jerry Krinock _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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RE: kev_vendor_code_find() call causes kernel panic...
by Alexander Klyuev 13 Aug '10

13 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: Acs7NW99xPc/0CkgT/iOqQXQZsc9LAAAKbbg Hi Vincent, Thanks, of course, I'm gonna do that. Cheers, - Alexander -----Original Message----- From: Vincent Lubet [mailto:vlubet@apple.com] Sent: August 13, 2010 6:18 PM To: Alexander Klyuev Cc: darwin-kernel(a)lists.apple.com Subject: Re: kev_vendor_code_find() call causes kernel panic... Alexander, To report a such bug you should open a problem report at https://bugreport.apple.com/ Thanks, Vincent On Aug 13, 2010, at 2:38 PM, Alexander Klyuev wrote: > Hi All, > > I already wrote about this issue: kev_vendor_code_find() call causes > kernel panic when network stack is not entirely up (net_str_id_lock > object is still uninitialized (NULL). > > Here is simplified call sequence: > -------------------------------------- > kev_vendor_code_find(...) > net_str_id_find_internal(...) > lck_mtx_lock(net_str_id_lock) <= where net_str_id_lock value is NULL. > ... kernel panic > ------------------------------------- > > However IMHO such a function MUST NEVER cause kernel crash whenever it > is called because it's possible to check whether a pointer argument > ("net_str_id_lock" in this case) is NULL before call to > lck_mtx_lock() > and return an error code not causing kernel panic. So that is > definitely a bug. > > Am I missing something? > > Thanks for further responses. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: kev_vendor_code_find() call causes kernel panic...
by Vincent Lubet 13 Aug '10

13 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Alexander, To report a such bug you should open a problem report at https://bugreport.apple.com/ Thanks, Vincent On Aug 13, 2010, at 2:38 PM, Alexander Klyuev wrote: > Hi All, > > I already wrote about this issue: kev_vendor_code_find() call > causes kernel panic when network stack is not entirely up > (net_str_id_lock object is still uninitialized (NULL). > > Here is simplified call sequence: > -------------------------------------- > kev_vendor_code_find(...) > net_str_id_find_internal(...) > lck_mtx_lock(net_str_id_lock) <= where net_str_id_lock value is NULL. > ... kernel panic > ------------------------------------- > > However IMHO such a function MUST NEVER cause kernel crash > whenever it is called because it's possible to check whether > a pointer argument ("net_str_id_lock" in this case) is NULL before call to > lck_mtx_lock() > and return an error code not causing kernel panic. So that is definitely a > bug. > > Am I missing something? > > Thanks for further responses. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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kev_vendor_code_find() call causes kernel panic...
by Alexander Klyuev 13 Aug '10

13 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: Acs7L9k27Q4SFCdWTtmVvS2FXNNPLw== Hi All, I already wrote about this issue: kev_vendor_code_find() call causes kernel panic when network stack is not entirely up (net_str_id_lock object is still uninitialized (NULL). Here is simplified call sequence: -------------------------------------- kev_vendor_code_find(...) net_str_id_find_internal(...) lck_mtx_lock(net_str_id_lock) <= where net_str_id_lock value is NULL. ... kernel panic ------------------------------------- However IMHO such a function MUST NEVER cause kernel crash whenever it is called because it's possible to check whether a pointer argument ("net_str_id_lock" in this case) is NULL before call to lck_mtx_lock() and return an error code not causing kernel panic. So that is definitely a bug. Am I missing something? Thanks for further responses. Best, - Alexander. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Preventing IOKit kext unload
by Nik Gervae 13 Aug '10

13 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com I'm not sure exactly what your kext does, but here is some more info: If you are using I/O Kit now, your kext should get unloaded automatically after about a minute when it has no instances of its defined classes. As long as the hardware is present, or have an IOUserClient connection (using a class defined by your kext!), you should have at least one instance of a class hanging around. There should be no need to unload such a kext explicitly, except in debug scenarios. So maybe you don't need to worry about preventing unload after all, as long as you manage autounload. If you are doing something completely in software and just riding on IOService life cycle, and all you want is autounload, you can enable and manage that for a generic kext on Snow Leopard or later using OSKextRetainKextWithLoadTag() and OSKextReleaseKextWithLoadTag(). You could retain the kext when a daemon connects, and release it when the daemon disconnects, and your kext would unload after about a minute when its retain count goes to zero. See OSKextLib.h for more info. (The old-school way of preventing a hybrid kext from autounloading was to just allocate an instance of a C++ class defined in the kext, and keep it around.) Nik Gervae Kext Management Engineer Apple, Inc. On 13 Aug, 2010, at 09:47 , Daniel Markarian wrote: > Hey Bogdan, > > http://lists.apple.com/archives/darwin-kernel/2010/Jan/msg00028.html > > Dan > > Le 2010-08-13 à 04:55, Bogdan Harjoc a écrit : > >> Hello, >> >> I have recently had to move from a generic kext to an IOKit one, in >> order to get the lifecycle functionality that IOKit offers. Since my >> kext exposes a control device, I used to return an error in the kext >> stop function if unregistering the control device failed (i.e. a >> daemon was connected to it). >> >> But none of the IOService callbacks that kexts usually override (stop, >> detach, free, ...) allow returning an error. And calling >> provider->retain() in device->start() doesn't prevent device->stop() >> from being called. Neither does device->adjustBusy(+1). >> >> What I am currently doing is I override device->terminate() and I >> return false if the kext is busy. But since no IOKit documentation >> recommends this, I assume it's not the proper way do prevent unload. >> >> My question is, how does one prevent cleanup when the kext is still >> busy ? (particularly when there are non-IOKit resources in use) >> >> Thank you. >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) >> Help/Unsubscribe/Update your Subscription: >> http://lists.apple.com/mailman/options/darwin-kernel/markarian%40apple.com >> >> This email sent to markarian(a)apple.com > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/darwin-kernel/ngervae%40apple.com > > This email sent to ngervae(a)apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Preventing IOKit kext unload
by Daniel Markarian 13 Aug '10

13 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hey Bogdan, http://lists.apple.com/archives/darwin-kernel/2010/Jan/msg00028.html Dan Le 2010-08-13 à 04:55, Bogdan Harjoc a écrit : > Hello, > > I have recently had to move from a generic kext to an IOKit one, in > order to get the lifecycle functionality that IOKit offers. Since my > kext exposes a control device, I used to return an error in the kext > stop function if unregistering the control device failed (i.e. a > daemon was connected to it). > > But none of the IOService callbacks that kexts usually override (stop, > detach, free, ...) allow returning an error. And calling > provider->retain() in device->start() doesn't prevent device->stop() > from being called. Neither does device->adjustBusy(+1). > > What I am currently doing is I override device->terminate() and I > return false if the kext is busy. But since no IOKit documentation > recommends this, I assume it's not the proper way do prevent unload. > > My question is, how does one prevent cleanup when the kext is still > busy ? (particularly when there are non-IOKit resources in use) > > Thank you. > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/darwin-kernel/markarian%40apple.com > > This email sent to markarian(a)apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Preventing IOKit kext unload
by Bogdan Harjoc 13 Aug '10

13 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:date:message-id :subject:from:to:content-type; bh=ZbAkFz56frp3NvDQopBRcfZBvOKNiF5e9IRhiFHdtdk=; b=cYDhMBrNE7T515ho1ZpZT//d9uSCg0aQmRCvyUPvTzBZEfXNJD+8HOOJoDLFdTo9T3 Ek8whUQk4CkYB4jYNV1AXk37zIZBaF5iLJhvNmXLu8rE5Xb/ijtCFiv/QZHcWFhyTJxK orRCaEcsMItM+H9Ld7WxkNJVBDcGiszTu84VM= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=Km1BSv3N0vbCVGjV3RGgmHbRwcYmSlUuXCsgaB6JLi6V0tM93hLNzx/GUfp07ATXiP itduqgDR0AEjiz+11XmYo7DCCIrezll5rFUaI3bM3oQJVH44jDpEKmwUq9wbaJtbvjZ/ giZd2eeWpwC7YaBGwIrOrvZMV/kmG3MKXUSpY= Hello, I have recently had to move from a generic kext to an IOKit one, in order to get the lifecycle functionality that IOKit offers. Since my kext exposes a control device, I used to return an error in the kext stop function if unregistering the control device failed (i.e. a daemon was connected to it). But none of the IOService callbacks that kexts usually override (stop, detach, free, ...) allow returning an error. And calling provider->retain() in device->start() doesn't prevent device->stop() from being called. Neither does device->adjustBusy(+1). What I am currently doing is I override device->terminate() and I return false if the kext is busy. But since no IOKit documentation recommends this, I assume it's not the proper way do prevent unload. My question is, how does one prevent cleanup when the kext is still busy ? (particularly when there are non-IOKit resources in use) Thank you. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Getting Physical address of a buffer
by shailesh jain 09 Aug '10

09 Aug '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=hKH77rQODiQAVUph5fNnvEuaIoVStl8VsOncC8fK5zE=; b=iDKrbdW/XPUXyBQk30nMwLY62x1KWjUoQUSaE+JGldBDodQYIx3z3gFvAf26nXKBMY gvZ900ox3PYDuw9di81gsd9J1kVGu4hpDveHFwJholoVpOnYLTN+7Jl2OPD+EEug7k6q dUi+D5mu31iQ/1yAoAXHDMqaG6nSmhtCOmrAU= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=A2rX6AHW9gugoikhGlIeKtYMBd1DqoWtSs3EJXpWfu2Ox62Vwx7zYe3u71zmXvwq+k CATyA0+ZKakpv7TZ5jLDV4vDkrzBRge3EuJXTanzM7Ef1z55dE5H7bBAx6tC0Y16pVU1 D+H24yMy09XIbIALR3ONpGJJxUI3g/jgUMsVg= On Mon, Aug 9, 2010 at 11:58 AM, chas williams - CONTRACTOR <chas(a)cmf.nrl.navy.mil> wrote: > On Mon, 9 Aug 2010 11:38:54 -0700 > shailesh jain <coolworldofshail(a)gmail.com> wrote: > >> @Mike - There are many instances where you will need physical >> addresses. Let me point out couple of them. >> >> - Memory ballooning is a technique where in guest driver allocates >> pages in the guest and passes down PPNs to the hypervisor. Hypervisor >> takes this pages and gives it to another Virtual machine for its use. >> Hypervisor does Physical address to Machine address (actual address in >> Physical ram. w/o virtualization you would call this Physical address) >> mapping. > > well you really dont need the physical addresses for these pages. you > just need a mechanism to map the same physical range to multiple > virtual ranges. you should probably be looking at the mach vm_* calls. > I am not sure I quite follow what you are talking about. This technique is more like pulling out one of the memory card from hardware and inserting into another physical box w/o any of the physical box knowing what happened. Because 1st box thinks that some driver is in need of memory and it is using it and 2nd box thinks "oh, I always had this memory." I clearly did not get what you are trying to say! >> - Hypervisor wants to do fast IO - i.e read/write from/to guest memory >> directly. Again you need physical address (different from Machine >> address.) > > cpu's generally do not operate on physical (or machine) addresses. > they generally go through your page mapper. so even if you have the > physical address, you will need to map it at some point so the > hypervisor can actually do something with the memory. although, i > suppose one could be passing around buffers from a driver but the > driver would handle the virtual/physical issue. > >> @Terry - Things are all good only when you have OS being the bottom >> most layer (you have EFI et all, but still) . With virtualization - >> you have Hypervisor underneath. Things are complicated then. >> >> >> >> Shailesh Jain >> >> >> >> >> >> >> >> On Sat, Aug 7, 2010 at 2:42 PM, James C >> <james.from.wellington(a)gmail.com> wrote: >> > Hi Terry and Shailesh, >> > >> > Re (4) below, hypothetically, could that include de-powering only >> > some parts of physical memory, when they're not needed? >> > >> > Shailesh, you know that the physical memory isn't contiguous. What >> > would you think of being given the physical address of the first >> > 0-byte segment? Why would that not meet your needs? >> > >> > Regards, >> > James. >> > >> >> Message: 4 >> >> Date: Fri, 6 Aug 2010 20:43:42 -0700 >> >> From: Terry Lambert <tlambert(a)apple.com> >> >> Subject: Re: Getting Physical address of a buffer >> >> To: shailesh jain <coolworldofshail(a)gmail.com> >> >> Cc: darwin-kernel(a)lists.apple.com >> >> Message-ID: <EC5425AB-CC65-4CF5-AFFA-1A015ED530B6(a)apple.com> >> >> Content-Type: text/plain; charset=us-ascii >> >> >> >> This question gets asked every once in a while: "why do I have to >> >> use OS routines to talk to hardware?". >> >> >> >> The basic answer is that there's virtual memory, there's wired >> >> memory, and then there's physical memory, and all three aren't the >> >> same thing. >> >> >> >> There are several reasons that an OS that runs its kernel in a >> >> virtual address space doesn't want to give you physical address >> >> information directly; let's briefly hit the top four on my >> >> personal top ten list: >> >> >> > <snip> >> >> (4) The OS likes to be kept informed of information for its own >> >> reasons so it can play tricks behind your back >> >> >> >> The tricks themselves don't matter, what matters is that you >> >> enable performance and power management winds by following the >> >> rules; if you don't follow the rules, and try to avoid the OS >> >> interfaces, you also avoid the OS signaling mechanisms that are >> >> used to implement these optimization. Unfortunately for you, this >> >> is like declaring a variable that is modified out of scope, and >> >> not marking it volatile: failure to notify the OS of the nature of >> >> your access means the OS gets to do any optimization it wants. >> >> For a volatile variable, that may mean not exiting the work loop >> >> when the signal handler fires. For a device driver, it generally >> >> means a panic in the driver. >> >> >> >> -- Terry >> > _______________________________________________ >> > Do not post admin requests to the list. They will be ignored. >> > Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) >> > Help/Unsubscribe/Update your Subscription: >> > http://lists.apple.com/mailman/options/darwin-kernel/coolworldofshail%40gma… >> > >> > This email sent to coolworldofshail(a)gmail.com >> > >> >> >> > > -- Shailesh Jain _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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