January 2006 - Darwin-kernel

Re: kmem_alloc
by Brian Bergstrand 22 Jan '06

22 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 #include <libkern/OSMalloc.h> HTH. On Jan 21, 2006, at 7:07 PM, Herbert wrote: Brian Bergstrand <http://www.bergstrand.org/brian/> PGP Key ID: 0xB6C7B6A2 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (Darwin) iD8DBQFD0vw7edHYW7bHtqIRAmgCAKD1QJGeFByAf/AFNgaHphljVZ5PRgCgzCUi ADYGzEB4FUeVMFd5J0L1lU8= =Wz4e -----END PGP SIGNATURE----- _______________________________________________ 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.… For 10.4, use the the KPI allocator OSMalloc() (and its counterpart OSFree(). Is kmem_alloc available on 10.4? The file it used to be in seems to be gone, and spotlight can find no trace of it except in the 10.3.9 sdk. This email sent to site_archiver(a)lists.apple.com

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Downloading Darwin Sources
by OL&L Lists 22 Jan '06

22 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thanks, James _______________________________________________ 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.… Is there any way to download the entire Darwin sources in one CD image or one archive rather than downloading each project? I need to search the entire Darwin source base for some strings and don't want to have to click each link just to get the whole thing. This email sent to site_archiver(a)lists.apple.com

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kmem_alloc
by Herbert 22 Jan '06

22 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.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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compiling for intel with gcc 4 and getting this error:
by Herbert 21 Jan '06

21 Jan '06

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Re: Is this chain of calls possible?
by William Kucharski 18 Jan '06

18 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Wednesday, January 18, 2006, at 12:19PM, Mike Smith <drivers(a)mu.org> wrote: >This isn't necessarily enough, as tail call optimisation may cause >you to miss any number of callers on the downward path. This is true; I was simply attempting to explain the more common case. William Kucharski kucharsk(a)mac.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: Is this chain of calls possible?
by Mike Smith 18 Jan '06

18 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Jan 18, 2006, at 10:57 AM, William Kucharski wrote: (gdb) x/i 0x000A9894 0xa9894 <Call_continuation+20>: mfsprg r3,1 (gdb) x/i 0x0011D2C8 0x11d2c8 <dlil_detach_filter+152>: mr. r31,r29 (gdb) x/i 0x0011D668 0x11d668 <dlil_input_packet+236>: mr. r30,r3 = Mike _______________________________________________ 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.… On Wednesday, January 18, 2006, at 09:40AM, Stephane Sudre <ssudre(a)intego.com> wrote: Remember also that the addresses in a traceback are the addresses the code will return TO when the called routine returns. To see the actual calling instruction, you need to (on PPC) look at the address in the traceback - 4, e.g.: This isn't necessarily enough, as tail call optimisation may cause you to miss any number of callers on the downward path. This email sent to site_archiver(a)lists.apple.com

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Re: Questions about debugging kernel panics
by Mike Smith 18 Jan '06

18 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Jan 17, 2006, at 1:37 PM, James Reynolds wrote: Let's see if going over this backtrace here helps at all. Thu Dec 15 20:03:23 2005 msmith% gdb /mach_kernel (gdb) x/i 0x0002A138 0x2a138 <ipc_task_enable+56>: lwz r0,88(r1) (gdb) x/i 0x00037960 0x37960 <task_set_64bit+68>: lwz r2,20(r31) (gdb) 0x37964 <task_set_64bit+72>: lwz r3,44(r2) (gdb) x/i 0x00265D14 0x265d14 <waitid+260>: addi r3,r1,64 = Mike _______________________________________________ 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.… So it has been a few months since I read that. Rereading it after having read a lot of other stuf helps a little more. But in reality, it raises more questions and answers only the one I had about what PC means. I'm sorry that this isn't easy. Sadly, it's not just understanding the backtraces that's complicated; they're not the only barrier to entry for this particular game. The good news is that practice is all it takes, along with a willingness to keep learning. But only slightly, as I'm still not sure exactly what it means, but I think I have found another bug. In examining 4 different machine panic logs within the last month, they are very similar. Anyway, 2 machines have a near exact logs. The DAR value, R1 value, and Exception states (sv) are the only things different, but the PC and backtraces are the same: Unresolved kernel trap(cpu 0): 0x600 - Alignment DAR=0x0000000001BCBEAE PC=0x00000000000A4F20 We took an alignment exception attempting to access the address 0x0000000001BCBEAE. It's only 16-bit aligned, so it was probably a 32- or 64-bit access. The instruction that tried to do this was at 0x00000000000A4F20. In addition, we took this while we were in the kernel. Latest crash info for cpu 0: Exception state (sv=0x23E24500) PC=0x000A4F20; MSR=0x00009030; DAR=0x01BCBEAE; DSISR=0x0A000000; LR=0x000750C0; R1=0x0CF13D00; XCP=0x00000018 (0x600 - Alignment) Backtrace: 0x0002A138 0x00037960 0x00265D14 0x00265F50 0x00265E30 0x002A8494 You can convert these back into function names using gdb. Here I am doing it against the wrong kernel version: etc. Again, this was against the wrong kernel version, so don't take the above as gospel. If you grab the debug kernel and the Darwin sources, you can get line number information and perhaps track it down to a small fragment of code. Once you've got a likely suspect, you're getting somewhere. Once you know what's failing, you need to look for causes. In your case here, where you see the same specific failure repeating over and over the cause is likely to be something with a deterministic consequence. You can rule out things like random memory corruption; instead you're looking for something with a small but nonzero chance of happening, often you'll be looking for a race condition or degenerate behaviour in the face of an unexpected resource shortage. For the specific example here, you almost certainly have a bad data or function pointer. Once you've found the code in question, you need to look at which pointer(s) it's attempting to dereference, and then at who might have changed them recently. One of those is likely to be your culprit. This email sent to site_archiver(a)lists.apple.com

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Re: Is this chain of calls possible?
by William Kucharski 18 Jan '06

18 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Wednesday, January 18, 2006, at 09:40AM, Stephane Sudre <ssudre(a)intego.com> wrote: >(gdb) x/i 0x000A9894 >0xa9894 <Call_continuation+20>: mfsprg r3,1 > >(gdb) x/i 0x0011D2C8 >0x11d2c8 <dlil_detach_filter+152>: mr. r31,r29 > >(gdb) x/i 0x0011D668 >0x11d668 <dlil_input_packet+236>: mr. r30,r3 Remember also that the addresses in a traceback are the addresses the code will return TO when the called routine returns. To see the actual calling instruction, you need to (on PPC) look at the address in the traceback - 4, e.g.: x/i 0x0011D668-4 This gets much uglier on x86, as Intel instructions are of variable length so there's no easy way to calculate just how many bytes back the previous instruction started... :-( William Kucharski kucharsk(a)mac.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: Is this chain of calls possible?
by Stephane Sudre 18 Jan '06

18 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On 18 janv. 06, at 18:26, Herb Petschauer wrote: I may be misinterpreting your email. I did the following That last result looks a lot like the beginning of an implementation for dlil_input_packet (so does the code for dlil_input_packet() in dlil.c). The code for dlil_input_packet is in dlil.c. Hope it is more clear. _______________________________________________ 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.… DevG5:/Volumes/Projects/Darwin_OpenSource/Darwin_10.4.3/xnu-792.6.22 me$ grep -rsI dlil_input_packet * bsd/net/dlil.c:int dlil_input_packet(struct ifnet *ifp, struct mbuf *m, char *frame_header); bsd/net/dlil.c: (void) dlil_input_packet(m->m_pkthdr.rcvif, m, header); bsd/net/dlil.c: (void) dlil_input_packet(ifp, m, header); bsd/net/dlil.c:dlil_input_packet(struct ifnet *ifp, struct mbuf *m, What is not in dlil.c is the call for dlil_input_packet from dlil_detach_filter (or the internal version). This email sent to site_archiver(a)lists.apple.com

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Re: Is this chain of calls possible?
by Herb Petschauer 18 Jan '06

18 Jan '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ZcZo6VwBY0ItItGzl7HkfFe91W/dnAWM551Qy7VceA68UBu9Y4OruvnHldI5x39aOM+riI/5t/C+CNtlvBwYeGa5lj9RN6Ij5Ah6FRx0+736qiZa0s4/Gwwh/Z/PG5O0iqF22v32MY06iO4EhULvh0JQ4mBrxW2BDrjMHJmbcGc= I may be misinterpreting your email. I did the following DevG5:/Volumes/Projects/Darwin_OpenSource/Darwin_10.4.3/xnu-792.6.22 me$ grep -rsI dlil_input_packet * bsd/net/dlil.c:int dlil_input_packet(struct ifnet *ifp, struct mbuf *m, char *frame_header); bsd/net/dlil.c: (void) dlil_input_packet(m->m_pkthdr.rcvif, m, header); bsd/net/dlil.c: (void) dlil_input_packet(ifp, m, header); bsd/net/dlil.c:dlil_input_packet(struct ifnet *ifp, struct mbuf *m, That last result looks a lot like the beginning of an implementation for dlil_input_packet (so does the code for dlil_input_packet() in dlil.c). ?? -H. On 1/18/06, Stephane Sudre <ssudre(a)intego.com> wrote: > (gdb) x/i 0x000A9894 > 0xa9894 <Call_continuation+20>: mfsprg r3,1 > > (gdb) x/i 0x0011D2C8 > 0x11d2c8 <dlil_detach_filter+152>: mr. r31,r29 > > (gdb) x/i 0x0011D668 > 0x11d668 <dlil_input_packet+236>: mr. r30,r3 > > > It looks strange to me that dlil_detach_filter is calling > dlil_input_packet because after a quick investigation I didn't find the > call in the xnu dlil.c source code. > > _______________________________________________ > 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/bogvardi%40gmail.com > > This email sent to bogvardi(a)gmail.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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