March 2003 - Darwin-kernel - lists.apple.com

Re: Disk Scheduling
by Shawn Erickson 25 Mar '03

25 Mar '03

On Monday, March 17, 2003, at 06:35 PM, Joey Echeverria wrote: I'm working on a project where we are using the Darwin kernel. I need to look into disk scheduling but was having a hard time traversing the source. I was hoping that you may be able to point me in the right direction. What do you mean by "disk scheduling" in this context? -Shawn _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: General routing Encapsulation
by Justin Walker 25 Mar '03

25 Mar '03

On Monday, Mar 24, 2003, at 16:59 US/Pacific, SQUID USER wrote: Hi, I am looking for General routing encapsulation (GRE) support for MAC OS. I did downloadthe kernel sources and looked for the GRE option in the kernel config files and did not find any. I don't believe that the GRE support is available in Darwin. I would appreciate if someone could direct me for a way to get GRE support on MAC OS. Crank up your editor :-} The GRE module is available on FreeBSD and a module exists on Linux. The kernel for Darwin/Mac OS X is pretty full-featured, i.e., most supported features are already turned on, so there is no need to build a kernel just to get a supported feature. You can build your own kernel, of course, but you would do that only to add features or debug problems (or learn the mysteries of kernel life...). The way to proceed is to get a copy of the FreeBSD 'gre' code that corresponds to the version of Mac OSX or Darwin you are running (for 10.2/6.x, that's FreeBSD 4.4, I think, with maybe a hint of 4.5 thrown in). Then you have some porting to do. The issue here is that, while the network stack architecture is BSD, the actual implementation differs from FreeBSD in several important respects. The 'NKE' architecture was designed to permit developers to add networking support at all levels of the system, and in particular, at the device layer, without forcing everything to be ethernet. You will have to see how other device types have been integrated into Darwin. Start with the 'gif' and 'stf' network interface code to see how the code changed from its BSD form to its Darwin form. The porting job will be straight-forward, but somewhat tedious. Regards, Justin -- Justin C. Walker, Curmudgeon-At-Large * Institute for General Semantics | Men are from Earth. | Women are from Earth. | Deal with it. *--------------------------------------*-------------------------------* _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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General routing Encapsulation
by SQUID USER 25 Mar '03

25 Mar '03

Hi, I am looking for General routing encapsulation (GRE) support for MAC OS. I did downloadthe kernel sources and looked for the GRE option in the kernel config files and did not find any. I would appreciate if someone could direct me for a way to get GRE support on MAC OS. The GRE module is available on FreeBSD and a module exists on Linux. Thanks, -Yogi Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: Dual-CPU Kernel Panic
by Brian Bergstrand 20 Mar '03

20 Mar '03

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Thursday, March 20, 2003, at 10:50 AM, Stockhoff, Cory wrote: > Hello Everybody, > > I apologize for the length of this post, but I hoped to provide enough > info to give somebody an "aha!" moment. > Aha! :) > Our product consists of user and kernel components implementing a VPN > client. The kernel component is a KEXT that processes inbound and > outbound > IP packets intercepted by a DLIL. The DLIL is pushed onto every > network > device that becomes active. > > The crash we are seeing is a kernel panic that occurs only on > multiple-CPU > hosts, and is infrequent. Our KEXT tries to allocate some kernel > memory by > calling "kmem_alloc()". The panic message is always "panic(cpu [0 or > 1]): > thread_invoke: preemption_level 1". The most reliable way to > duplicate the > problem is to engage the software (i.e. connect to a VPN switch via an > encrypted VPN tunnel), mount a remote shared volume (AppleTalk over > IP), and > do heavy reads and writes to the volume. > > Our customers have seen the problem on both Jaguar (10.2.x) and Puma > (10.1.x) OS's. Our testing and debugging has been on Jaguar hosts, > 10.2.3 > (Darwin 6.3). Our application is built on Puma. > > Various checks have been tried, none successful: > 1) Don't call kmem_alloc() if preemption level is 1. It turns out > that > the preemption level is often 1 during normal operation, and is > usually not a problem. However, not returning allocated memory > every time preemption level is 1 does cause problems for our > software. > If you are holding a spinlock or, you are allocating from a network callback thread, then you may see this crash when allocating memory. kmem_alloc can block and blocking is a big no-no when holding a spinlock or when interrupts are disabled. If alloc does block, then you will get this panic, if it doesn't block then you won't panic. Unfortunately, there is no easy way to tell if an allocation will cause alloc to block. To get around this problem, I allocated a reserve pool at kext load time and at allocation time if interrupts are disabled and kalloc_noblock() returns nil, I grab a block from this reserve. This worked for me in this particular case, because we always disable interrupts when grabbing a spinlock. Here is some pseudo code if (interrupts enabled) { mem = kalloc(size); } else { mem = kalloc_noblock(size); if (!mem) mem = my_reserve_alloc(); } return (mem); > > The stack trace can vary a bit, but this one is typical (and from > Jaguar): > > 0x000856cc print_backtrace+176 > 0x00085afc Debugger+108 > 0x000287a8 panic+488 > 0x00033eec thread_invoke+72 > 0x000344d0 thread_block_reason+212 > 0x0008d51c mlInUse+16 > 0x00060b60 vm_fault_wire_fast+284 > 0x00064f88 vm_map_wire_nested+2988 > 0x000651a0 vm_map_wire+120 > 0x00061a78 kernel_memory_allocate+600 > You can see the problem in the backtrace, the thread tries to block because the allocation could not be immediately filled (thread_block_reason). BTW, this problem can happen on single CPU machines too, but is much more likely to happen on dualies. HTH. Brian Bergstrand <http://www.classicalguitar.net/brian/> PGP Key ID: 0xB6C7B6A2 It is easy to convert a bug to a feature; document it. - The Microsoft Employee Handbook, p.215, section B, article VII - -----BEGIN PGP SIGNATURE----- Version: PGP 8.0 iQA/AwUBPnnuwXnR2Fu2x7aiEQIpAACfZkR8pRqVjeQniPIv2Ynjh/IV5+4AoLPO S/GvkjmAqouvnX+GDOTQebJ/ =iXu+ - -----END PGP SIGNATURE----- Brian Bergstrand <http://www.classicalguitar.net/brian/> PGP Key ID: 0xB6C7B6A2 Genius may have its limitations, but stupidity is not thus handicapped. - - Elbert Hubbard -----BEGIN PGP SIGNATURE----- Version: PGP 8.0 iQA/AwUBPnnu+3nR2Fu2x7aiEQIbDACfVgmMfGfXWvZdALXDuYaz4AK88XUAoNia O84epg7QHYQUZgxzwSA3avXG =nwFc -----END PGP SIGNATURE----- _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Dual-CPU Kernel Panic
by Stockhoff, Cory 20 Mar '03

20 Mar '03

Hello Everybody, I apologize for the length of this post, but I hoped to provide enough info to give somebody an "aha!" moment. Our product consists of user and kernel components implementing a VPN client. The kernel component is a KEXT that processes inbound and outbound IP packets intercepted by a DLIL. The DLIL is pushed onto every network device that becomes active. The crash we are seeing is a kernel panic that occurs only on multiple-CPU hosts, and is infrequent. Our KEXT tries to allocate some kernel memory by calling "kmem_alloc()". The panic message is always "panic(cpu [0 or 1]): thread_invoke: preemption_level 1". The most reliable way to duplicate the problem is to engage the software (i.e. connect to a VPN switch via an encrypted VPN tunnel), mount a remote shared volume (AppleTalk over IP), and do heavy reads and writes to the volume. Our customers have seen the problem on both Jaguar (10.2.x) and Puma (10.1.x) OS's. Our testing and debugging has been on Jaguar hosts, 10.2.3 (Darwin 6.3). Our application is built on Puma. Various checks have been tried, none successful: 1) Don't call kmem_alloc() if preemption level is 1. It turns out that the preemption level is often 1 during normal operation, and is usually not a problem. However, not returning allocated memory every time preemption level is 1 does cause problems for our software. 2) Tried a thread_funnel_switch(). No funnel was being held by the thread at the time, so this caused its own panic. 3) Examined the size of the requested kernel block. The block requested when the panic occurs does not look unusual. The requested sizes seen were anywhere from 10 to over 1000 bytes during normal operation. The request that caused one panic was about 700 bytes. The stack trace can vary a bit, but this one is typical (and from Jaguar): 0x000856cc print_backtrace+176 0x00085afc Debugger+108 0x000287a8 panic+488 0x00033eec thread_invoke+72 0x000344d0 thread_block_reason+212 0x0008d51c mlInUse+16 0x00060b60 vm_fault_wire_fast+284 0x00064f88 vm_map_wire_nested+2988 0x000651a0 vm_map_wire+120 0x00061a78 kernel_memory_allocate+600 Looking through the Darwin source, the calls appear as: - vm_fault_wire_fast - mutex(&vm_page_queue_lock) - mlInUse - mutex_lock_wait - thread_sleep_interlock - assert_wait - interlock_unlock - thread_block - thread_block_reason (continuation, AST_NONE) - thread_invoke - panic("thread_invoke: preemption_level %d\n", cpu_data[cpu_number()].preemption_level); I don't quite understand how the preemption level gets set in this case, but it looks like it is done in the "interlock_unlock" function, and that "thread_sleep_interlock" shouldn't be calling both "interlock_unlock" and "thread_block". Whether or not I'm correct, is there a workaround for this panic that can be implemented in my code? Or, if it's an OS problem, will this be fixed in a future release (or is it already fixed in 10.2.4)? Cheers, Cory _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: Kernel Panic with DevSDK.pkg
by Bernard Desgraupes 19 Mar '03

19 Mar '03

Brian, thanks for the suggestion but it did not solve my problem. The only difference is that I have a slightly different panic.log. Instead of panic(cpu 0): hfs_remove: attempting to delete a non-empty file! it now says something about locking again itself. Nevermind, I chose the brutal solution because I had enough with this long lasting problem. I decided to erase my startup disk and reinstall both OS9 and OSX. Now I have a fresh and clean installation (won't last long !!). This is also why I lost the last panic.log and quote from memory the message above. Thanks for your help Bernard > Bernard, > > This looks to be an older Jaguar Kernel, what revision of Jaguar are you using? I suggest upgrading to 10.2.4. There is probably a VFS or HFS file system stack bug in this older kernel. Upgrade first and see if that solves your problem, chances are it will. In general, if you want to understand more about kernel panics and how to read them, check out this tech document on apple's website: > > http://developer.apple.com/technotes/tn2002/tn2063.html > > -Brian Tabone > > On Tuesday, March 18, 2003, at 10:17AM, Bernard Desgraupes <bdesgraupes(a)easyconnect.fr> wrote: > > >Hi, > > > > > >I already asked this question on the ProjectBuilder list but did not get > >any answer. If this is not the right place to ask, please forgive me and > >tell me where to ask. > > > >I get a KERNEL PANIC when trying to install the latest DevTools under > >Jaguar: the culprit is the DevSDK.pkg package (the others install fine). > >I'm installing with the Devtools CD-ROM which came with Jaguar. I have > >succesfully installed Jaguar over my previous OSX on which there was > >already the developer software. > > > >The panic.log contains information which I'm unable to interpret (though > >I have read entirely the TN 2063). Here is what it says: > > > > ********* > > > > Tue Mar 18 16:18:33 2003 > > > > > > panic(cpu 0): hfs_remove: attempting to delete a non-empty file! > > Latest stack backtrace for cpu 0: > > Backtrace: > > 0x0008593C 0x00085D6C 0x00028B8C 0x001BCCCC 0x000B7244 0x00203A1C > >0x00092830 0x65646C6F > > Proceeding back via exception chain: > > Exception state (sv=0x0DF0E500) > > PC=0x900105AC; MSR=0x0200F030; DAR=0x00104000; DSISR=0x42000000; > >LR=0x000048B8; R1=0xBFFFDF50; XCP=0x00000030 (0xC00 - System call) > > > > Kernel version: > > Darwin Kernel Version 6.0: > > Sat Jul 27 13:18:52 PDT 2002; root:xnu/xnu-344.obj~1/RELEASE_PPC > > > > ********* > > > > > > > > > >Can someone give me a clue about how I can track this further and > >understand what is the offending file ("attempting to delete a non-empty > >file"). > > > >TIA > > > >Bernard > >_______________________________________________ > >darwin-kernel mailing list | darwin-kernel(a)lists.apple.com > >Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel > >Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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what kind of driver do I need to write?
by Jasendo Technologies Ltd. 19 Mar '03

19 Mar '03

Hello, I need to write a driver for a device that controls several screens, It is the first time I have to write a driver for darwin/macos x so I am not sure where the best place to start is. I would really appreciate it if someone can give me some advice. This device is used in an exhibition place to show several videos and demonstrations in several screens at the same time. The screens are independent and can show different information at any given time, they also can be co-ordinated as a big screen or in the simplest case, they can just show the same information. Our immediate need is to be able to use the device to show different information in the screens, we need to be able to switch with software the screen where the Quartz system is painting. I believe the options are frame buffer drivers or HID drivers, what would be the best approach for this? thank you very much in advance for your help Tenoch de La Cruz Jasendo Technologies Ltd. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: Kernel Panic with DevSDK.pkg
by Brian Tabone 18 Mar '03

18 Mar '03

Bernard, This looks to be an older Jaguar Kernel, what revision of Jaguar are you using? I suggest upgrading to 10.2.4. There is probably a VFS or HFS file system stack bug in this older kernel. Upgrade first and see if that solves your problem, chances are it will. In general, if you want to understand more about kernel panics and how to read them, check out this tech document on apple's website: http://developer.apple.com/technotes/tn2002/tn2063.html -Brian Tabone On Tuesday, March 18, 2003, at 10:17AM, Bernard Desgraupes <bdesgraupes(a)easyconnect.fr> wrote: >Hi, > > >I already asked this question on the ProjectBuilder list but did not get >any answer. If this is not the right place to ask, please forgive me and >tell me where to ask. > >I get a KERNEL PANIC when trying to install the latest DevTools under >Jaguar: the culprit is the DevSDK.pkg package (the others install fine). >I'm installing with the Devtools CD-ROM which came with Jaguar. I have >succesfully installed Jaguar over my previous OSX on which there was >already the developer software. > >The panic.log contains information which I'm unable to interpret (though >I have read entirely the TN 2063). Here is what it says: > > ********* > > Tue Mar 18 16:18:33 2003 > > > panic(cpu 0): hfs_remove: attempting to delete a non-empty file! > Latest stack backtrace for cpu 0: > Backtrace: > 0x0008593C 0x00085D6C 0x00028B8C 0x001BCCCC 0x000B7244 0x00203A1C >0x00092830 0x65646C6F > Proceeding back via exception chain: > Exception state (sv=0x0DF0E500) > PC=0x900105AC; MSR=0x0200F030; DAR=0x00104000; DSISR=0x42000000; >LR=0x000048B8; R1=0xBFFFDF50; XCP=0x00000030 (0xC00 - System call) > > Kernel version: > Darwin Kernel Version 6.0: > Sat Jul 27 13:18:52 PDT 2002; root:xnu/xnu-344.obj~1/RELEASE_PPC > > ********* > > > > >Can someone give me a clue about how I can track this further and >understand what is the offending file ("attempting to delete a non-empty >file"). > >TIA > >Bernard >_______________________________________________ >darwin-kernel mailing list | darwin-kernel(a)lists.apple.com >Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel >Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Kernel Panic with DevSDK.pkg
by Bernard Desgraupes 18 Mar '03

18 Mar '03

Hi, I already asked this question on the ProjectBuilder list but did not get any answer. If this is not the right place to ask, please forgive me and tell me where to ask. I get a KERNEL PANIC when trying to install the latest DevTools under Jaguar: the culprit is the DevSDK.pkg package (the others install fine). I'm installing with the Devtools CD-ROM which came with Jaguar. I have succesfully installed Jaguar over my previous OSX on which there was already the developer software. The panic.log contains information which I'm unable to interpret (though I have read entirely the TN 2063). Here is what it says: ********* Tue Mar 18 16:18:33 2003 panic(cpu 0): hfs_remove: attempting to delete a non-empty file! Latest stack backtrace for cpu 0: Backtrace: 0x0008593C 0x00085D6C 0x00028B8C 0x001BCCCC 0x000B7244 0x00203A1C 0x00092830 0x65646C6F Proceeding back via exception chain: Exception state (sv=0x0DF0E500) PC=0x900105AC; MSR=0x0200F030; DAR=0x00104000; DSISR=0x42000000; LR=0x000048B8; R1=0xBFFFDF50; XCP=0x00000030 (0xC00 - System call) Kernel version: Darwin Kernel Version 6.0: Sat Jul 27 13:18:52 PDT 2002; root:xnu/xnu-344.obj~1/RELEASE_PPC ********* Can someone give me a clue about how I can track this further and understand what is the offending file ("attempting to delete a non-empty file"). TIA Bernard _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: Max number partitions per disk??
by David Krauss 18 Mar '03

18 Mar '03

--- Dan Markarian <markarian(a)apple.com> wrote: > Hi Wade, > > A specific partition scheme might have limits, but > there is no system > limit and has never been. The BSD disklabel is just > another partition > style in this big picture. The system has no > dependence on a specific > partition style, architecturally. Not only that, but there's only 1 partition style Open Firmware (that I've seen) can boot, which is Apple's. And that uses 1 block per partition in the map, with a 4 byte count of partitions, instead of 1 block for the whole map. So unless the user is really trying to screw you up, there's really no limit. - Potatoswatter Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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