January 2010 - Darwin-kernel

Re: KEXT loading issue on 10.6.*
by Kevin Brock 19 Jan '10

19 Jan '10

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Re: KEXT loading issue on 10.6.*
by Ryan Hankins 19 Jan '10

19 Jan '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com User-agent: Thunderbird 2.0.0.23 (Macintosh/20090812) I've got a couple of KEXTs which have one binary for 10.5/10.6, using various Xcode build options to distinguish 32 from 64 etc. Each of these also has a sub-KEXT which is for 10.4, located in Contents/Plugins. The problem I'm having is that on 10.6.* sometimes, generally after an upgrade, the 10.4 version of one of the KEXTs is loading instead of the 10.5/10/6 version. The 10.5+ KEXT has: - KPI versions 9.0.0 or greater - Probe score of 2000 The 10.4 version of the KEXT specifies: - KPI versions 8.0.0 or greater - Probe score of 100 Usually everything is fine, and after a reboot everything is always fine, so I know that he right files are getting installed. I don't see any messages in system.log that would indicate a problem. Does anyone have any ideas on this? Kevin _______________________________________________ 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/rqh%40small-tree.com This email sent to rqh(a)small-tree.com -- Ryan Hankins Software Engineer Small Tree Communications www.small-tree.com rqh(a)small-tree.com +1 651 209-6509 x303 _______________________________________________ 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.… Interesting; we are seeing this issue,, or a similar one, as well. In fact, we were just talking about it today. 10.6 seems to ignore the kext in the main directory, and instead attempts to load the 10.5 one under Plugins. One thing that seems to help is removing the Plugins directory in your kext. Does that help in your case? I have been wondering if this is a bug in Apple's kext loading routines. -Ryan This email sent to site_archiver(a)lists.apple.com

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KEXT loading issue on 10.6.*
by Kevin Brock 19 Jan '10

19 Jan '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com I've got a couple of KEXTs which have one binary for 10.5/10.6, using various Xcode build options to distinguish 32 from 64 etc. Each of these also has a sub-KEXT which is for 10.4, located in Contents/Plugins. The problem I'm having is that on 10.6.* sometimes, generally after an upgrade, the 10.4 version of one of the KEXTs is loading instead of the 10.5/10/6 version. The 10.5+ KEXT has: - KPI versions 9.0.0 or greater - Probe score of 2000 The 10.4 version of the KEXT specifies: - KPI versions 8.0.0 or greater - Probe score of 100 Usually everything is fine, and after a reboot everything is always fine, so I know that he right files are getting installed. I don't see any messages in system.log that would indicate a problem. Does anyone have any ideas on this? Kevin _______________________________________________ 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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Ignore: Racy DMESG connect
by Godfrey van der Linden 18 Jan '10

18 Jan '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On 2010-01-18, at 3:32 PM, Godfrey van der Linden wrote: > This isn't a race, see bottom of email! > > On 2010-01-18, at 3:16 PM, Godfrey van der Linden wrote: > >> G'day, all networking types. >> >> I've recently tripped over a kernel race when attempting to connect with a DGRAM socket. This is the code fragment that is causing problems >> >> struct sockaddr_un sa2; >> struct sockaddr_storage saLocal; >> socklen_t saLocalLen; >> >> sa2.sun_family = AF_UNIX; >> strcpy(sa2.sun_path, kDefSocketName2); >> (void) unlink(kDefSocketName2); >> >> sys_test(fd_skt = socket(AF_UNIX, SOCK_DGRAM, 0), >> "Can't open DGRAM socket %d", child_pid); >> sys_test(bind(fd_skt, (struct sockaddr *) &sa2, sizeof(sa2)), >> "Can't bind DGRAM socket %d", child_pid); >> >> // Wait for first client message for connecting >> sys_test(recvfrom(fd_skt, msg, sizeof(msg), /* flags */ 0, >> (struct sockaddr *) &saLocal, &saLocalLen), >> "Error reading first message"); >> #if NOCRASH >> saP = (struct sockaddr_un *) &saLocal; >> #endif // NOCRASH >> sys_test(connect(fd_skt, (struct sockaddr *) &saLocal, saLocalLen), >> "Can't connect to client %d", child_pid); >> >> notes: >> 1> sys_test is a macro that checks the result for -1 and crashes with the error if necessary. >> 2> sys_test is implemented within a do{ ... } while(0), i.e. the macros don't interact). >> 3> the server is single threaded and runs in its own process after a fork(). >> 4> The code is compiled with -O0 (no optimisation) >> 5> I'm running on an '06 intel iMac, which is dual core. >> >> When I compile and run with -DNOCRASH=1 connect never seems to fail. >> >> However if the connect directly follows the recvfrom then I get a >> "nwmark(main): Can't connect to client 53673 - Invalid argument(22)" >> about 50% of the time. Process is single threaded (see note <3>), so the saLocal variable is not being scribbled on between the recvfrom and the connect. >> >> Has anybody seen the kernel race in this way before? Should I submit a bug? > > It is not a race! > > I tried recvfrom()/usleep(100)/connect() it does not fix the problem! > > Is there any way that the sockaddr_storage returned from the recvfrom could be in an odd state. If I refer to it, even by just assigning the address this problem doesn't reproduce. RTFM, mea-culpa. The address_len arg to recvfrom is for input and output and I didn't initialise it, oops. Interesting that the problem was not deterministic, it only failed occasionally, some sort of weird initialisation race between the two legs of the fork() perhaps or some other init time signal? Godfrey _______________________________________________ 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: Racy DMESG connect
by Godfrey van der Linden 18 Jan '10

18 Jan '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com This isn't a race, see bottom of email! On 2010-01-18, at 3:16 PM, Godfrey van der Linden wrote: > G'day, all networking types. > > I've recently tripped over a kernel race when attempting to connect with a DGRAM socket. This is the code fragment that is causing problems > > struct sockaddr_un sa2; > struct sockaddr_storage saLocal; > socklen_t saLocalLen; > > sa2.sun_family = AF_UNIX; > strcpy(sa2.sun_path, kDefSocketName2); > (void) unlink(kDefSocketName2); > > sys_test(fd_skt = socket(AF_UNIX, SOCK_DGRAM, 0), > "Can't open DGRAM socket %d", child_pid); > sys_test(bind(fd_skt, (struct sockaddr *) &sa2, sizeof(sa2)), > "Can't bind DGRAM socket %d", child_pid); > > // Wait for first client message for connecting > sys_test(recvfrom(fd_skt, msg, sizeof(msg), /* flags */ 0, > (struct sockaddr *) &saLocal, &saLocalLen), > "Error reading first message"); > #if NOCRASH > saP = (struct sockaddr_un *) &saLocal; > #endif // NOCRASH > sys_test(connect(fd_skt, (struct sockaddr *) &saLocal, saLocalLen), > "Can't connect to client %d", child_pid); > > notes: > 1> sys_test is a macro that checks the result for -1 and crashes with the error if necessary. > 2> sys_test is implemented within a do{ ... } while(0), i.e. the macros don't interact). > 3> the server is single threaded and runs in its own process after a fork(). > 4> The code is compiled with -O0 (no optimisation) > 5> I'm running on an '06 intel iMac, which is dual core. > > When I compile and run with -DNOCRASH=1 connect never seems to fail. > > However if the connect directly follows the recvfrom then I get a > "nwmark(main): Can't connect to client 53673 - Invalid argument(22)" > about 50% of the time. Process is single threaded (see note <3>), so the saLocal variable is not being scribbled on between the recvfrom and the connect. > > Has anybody seen the kernel race in this way before? Should I submit a bug? It is not a race! I tried recvfrom()/usleep(100)/connect() it does not fix the problem! Is there any way that the sockaddr_storage returned from the recvfrom could be in an odd state. If I refer to it, even by just assigning the address this problem doesn't reproduce. _______________________________________________ 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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Racy DMESG connect
by Godfrey van der Linden 18 Jan '10

18 Jan '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com G'day, all networking types. I've recently tripped over a kernel race when attempting to connect with a DGRAM socket. This is the code fragment that is causing problems struct sockaddr_un sa2; struct sockaddr_storage saLocal; socklen_t saLocalLen; sa2.sun_family = AF_UNIX; strcpy(sa2.sun_path, kDefSocketName2); (void) unlink(kDefSocketName2); sys_test(fd_skt = socket(AF_UNIX, SOCK_DGRAM, 0), "Can't open DGRAM socket %d", child_pid); sys_test(bind(fd_skt, (struct sockaddr *) &sa2, sizeof(sa2)), "Can't bind DGRAM socket %d", child_pid); // Wait for first client message for connecting sys_test(recvfrom(fd_skt, msg, sizeof(msg), /* flags */ 0, (struct sockaddr *) &saLocal, &saLocalLen), "Error reading first message"); #if NOCRASH saP = (struct sockaddr_un *) &saLocal; #endif // NOCRASH sys_test(connect(fd_skt, (struct sockaddr *) &saLocal, saLocalLen), "Can't connect to client %d", child_pid); notes: 1> sys_test is a macro that checks the result for -1 and crashes with the error if necessary. 2> sys_test is implemented within a do{ ... } while(0), i.e. the macros don't interact). 3> the server is single threaded and runs in its own process after a fork(). 4> The code is compiled with -O0 (no optimisation) 5> I'm running on an '06 intel iMac, which is dual core. When I compile and run with -DNOCRASH=1 connect never seems to fail. However if the connect directly follows the recvfrom then I get a "nwmark(main): Can't connect to client 53673 - Invalid argument(22)" about 50% of the time. Process is single threaded (see note <3>), so the saLocal variable is not being scribbled on between the recvfrom and the connect. Has anybody seen the kernel race in this way before? Should I submit a bug? Cheers Godfrey _______________________________________________ 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: VM object cache misses
by Michael Smith 15 Jan '10

15 Jan '10

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Re: VM object cache misses
by Quinn 15 Jan '10

15 Jan '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Check out the comments associated with VM_OBJECT_CACHE in the following file: <http://www.opensource.apple.com/source/xnu/xnu-1456.1.26/osfmk/vm/vm_object…> S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Relations, Developer Technical Support, Core OS/Hardware At 15:16 +1100 15/1/10, Godfrey van der Linden wrote: What is the "Object cache" reported by vm_stat I believe [1] this is a cache of vm_object_t objects whose reference counts have hit zero but which persist in the hope that they get reused. For example, if you map a file, the kernel creates a vm_object_t to represent the file to the VM subsystem. If you unmap it, the vm_object_t's reference count would drop to zero, but the object would persist in the cache. If you then immediately remapped it, it wouldn't need to recreate that object (saving both the object creation time and preserving the resident pages associated with the object). and why is its hit-rate so low? I don't understand the dynamic behaviour of the VM subsystem well enough to answer that question. I will note that the cache is pretty small (vm_object_cached_max defaults to 512). [1] I don't have time to trace the logic from vm_stat to this vm_object_t cache, but I'm pretty confident about that this is what it's talking about. _______________________________________________ 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: VM object cache misses
by Steve Checkoway 15 Jan '10

15 Jan '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Jan 14, 2010, at 10:55 PM, Godfrey van der Linden wrote: I get: Object cache: 933864 hits of 5398556 lookups (17% hit rate) I have no idea what it is though. -- Steve Checkoway _______________________________________________ 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 What I meant was cache lookup only occurs on average twice a second, and the hit rate is only every hour and a half on average. Seems like a false optimisation smime.p7s

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Re: VM object cache misses
by Godfrey van der Linden 15 Jan '10

15 Jan '10

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