July 2005 - Darwin-kernel - lists.apple.com

Re: sock_receive_internal() and its (ab)use of uio
by Sam Vaughan 26 Jul '05

26 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com <http://lkcd.sourceforge.net/doc/index.html> Sam _______________________________________________ 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.… We don't have a good way to deliver new headers with software updates. No header means no prototype or documentation for the new function. Really? I've been half expecting Software Update to modify my Kernel.framework Headers directory during 10.4.x updates. The motivation of the KPI is to give us the freedom to fix bugs, add features, and improve performance without breaking third party kexts. The whole point of the KPI is that we can make big changes internally without making any change to the KPI. We don't want to go crazy and have a dozen ways to do everything. The more functions we supply, the more we have to maintain and the more limits we have on the changes we can make in the future. We have to balance requests for everything every developer ever asks for with our need to have a clear, coherent, lightweight, and easily maintainable interface for developers. Agreed. I'd still like to push for the return of uio interfaces per my Radar report though, especially considering the simplicity of the implementation on the KPI side: if have uio, pass it down, else create one using the msghdr. Implementing the code to generate a new set of iovecs to specify the I/O region of a uio was non-trivial once all the edge cases and performance issues were taken into account. Small iovec count operations are handled using iovecs on the caller's stack, operations that start and end on iovec boundaries in the original uio use the original uio's iovecs, and if all else fails, new iovecs are allocated. It's all encapsulated in a function to be called from sending or receiving code, and the debug-mode tracing and verification code at the end of it is nearly as big as the function itself. There are a variety of reasons not to use uname -r as you suggest above. I would hope the thing that stops most developers is their interest in shipping a robust, quality product to their customers. When you are writing kernel code, you need to be careful. If you link directly against the kernel, you are probably doing it because you're doing something skanky. Some day, when some assumption you are making breaks, your customer will suffer. All the finger pointing in the world won't bring back the lost productivity and data. If we don't work together, the end user suffers. I fully understand this, hence the smiley for facetiousness :o) On the other hand, our customers aren't Joe Users, their system administrators govern when their machines are upgraded and we could mandate a particular OS minor point release if we had to. It's not that I don't want to use the KPI, it's just that there are so many areas where things are missing. Sockets are just this week. I'm also trying to deal with setting arbitrary dev_t values in buf_t objects, accessing the try variants and determining the current state of read-write locks, getting a device switch table entry from a major number, interrupting threads sleeping on sockets, timeout/untimeout, thread_abort_safely, ... and that's just the platform support code. Who knows what vfs, vnode lifetime, lookup, mmap and UBC issues still await! Ah it's all fun and I don't want this to sound like a rant, I'm just trying to put this issue in perspective. I'm VERY pleased to have funnels out of the picture, to have so much of the lookup and name caching work handled for us, the prospect of good lock statistics à la Solaris, and maybe even practical kernel dumps. All we need now is a proper run-time kernel debugger. Hmmm... mcrash anyone? This email sent to site_archiver(a)lists.apple.com

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Re: Serious Bug
by Terry Lambert 26 Jul '05

26 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thanks for investigating the bug. -- Terry /* @@@@@@@@@@@@@@@@@@@*/ #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/event.h> int main (int argc, char **argv) { int kq; struct kevent ke; if (argc < 1) return -1; if ((kq = kqueue ()) < 0) { fprintf (stderr, "kqueue creation error\n"); return -1; } if (kevent(kq, &ke, 1, NULL, 0, NULL) < 0) { fprintf (stderr, "kevent set error\n"); return -1; } while (1) { memset(&ke, 0, sizeof(struct kevent)); if (kevent(kq, NULL, 0, &ke, 1, NULL) < 0) { fprintf (stderr, "kevent get error\n"); return -1; } if (ke.fflags & NOTE_FORK) printf("%d forked\n", ke.ident); if (ke.fflags & NOTE_CHILD) printf("child of %d is %d\n", ke.data, ke.ident); if (ke.fflags & NOTE_TRACKERR) printf("NOTE_TRACK error\n"); } return 0; } /* @@@@@@@@@@@@@@@@@@@*/ LOCATION OF BUG: Whoever re-organized the kqueue/kevent code, please fix it. Thanks, Lakshmipathy This email sent to tlambert(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.… You should file a bug report (http://bugreporter.apple.com) As Justin usually points out, this list isn't an official (or even an unofficial) channel for reporting bugs to Apple. On Jul 26, 2005, at 10:46 AM, B. S. N. Lakshmipathy wrote: Hi all, The kernel released with 10.4.* (Tiger) has a serious bug. The following user program causes kernel panic. EV_SET (&ke, atoi (argv[1]), EVFILT_PROC, EV_ADD, NOTE_FORK | NOTE_TRACK, 0, NULL); The problem is with the NULL pointer reference in fp_lookup() in bsd/kern/kern_descrip.c. The function call sequence is fork() -> fork1 () -> knote () -> filt_proc () -> kevent_register () -> fp_lookup (). filt_proc () calls kevent_register () with NULL as third argument. (kern_event.c:501), which is referenced in fp_lookup () without check for NULL. _______________________________________________ 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/tlambert% 40apple.com This email sent to site_archiver(a)lists.apple.com

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Serious Bug
by B. S. N. Lakshmipathy 26 Jul '05

26 Jul '05

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:mime-version:content-transfer-encoding:message-id:content-type:to:subject:date:x-mailer:from; b=rvDaLOWAP9xIlFYGlaBKtRrNqKUDNGm5JfGWM4MVVWN+n182kfwktllenq9oAfG4FrUUydxw/F/57rIoVYhQ8pG0NFd5S0ceiqSXtRY3c8KPQdEQI4KDu2p4NRmWDMN7mtw2/CbiVfbElJOb597p3/iwyAr1/vcnhE9P+Yd4Cb4= /* @@@@@@@@@@@@@@@@@@@*/ #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <sys/event.h> int main (int argc, char **argv) { int kq; struct kevent ke; if (argc < 1) return -1; if ((kq = kqueue ()) < 0) { fprintf (stderr, "kqueue creation error\n"); return -1; } if (kevent(kq, &ke, 1, NULL, 0, NULL) < 0) { fprintf (stderr, "kevent set error\n"); return -1; } while (1) { memset(&ke, 0, sizeof(struct kevent)); if (kevent(kq, NULL, 0, &ke, 1, NULL) < 0) { fprintf (stderr, "kevent get error\n"); return -1; } if (ke.fflags & NOTE_FORK) printf("%d forked\n", ke.ident); if (ke.fflags & NOTE_CHILD) printf("child of %d is %d\n", ke.data, ke.ident); if (ke.fflags & NOTE_TRACKERR) printf("NOTE_TRACK error\n"); } return 0; } /* @@@@@@@@@@@@@@@@@@@*/ LOCATION OF BUG: Whoever re-organized the kqueue/kevent code, please fix it. Thanks, Lakshmipathy _______________________________________________ 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.… Hi all, The kernel released with 10.4.* (Tiger) has a serious bug. The following user program causes kernel panic. EV_SET (&ke, atoi (argv[1]), EVFILT_PROC, EV_ADD, NOTE_FORK | NOTE_TRACK, 0, NULL); The problem is with the NULL pointer reference in fp_lookup() in bsd/kern/kern_descrip.c. The function call sequence is fork() -> fork1 () -> knote () -> filt_proc () -> kevent_register () -> fp_lookup (). filt_proc () calls kevent_register () with NULL as third argument. (kern_event.c:501), which is referenced in fp_lookup () without check for NULL. This email sent to site_archiver(a)lists.apple.com

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Re: current_task(), struct proc...
by Herb Petschauer 26 Jul '05

26 Jul '05

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:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=nApPSIK3md+FKIWGa/JXPkPOIY6O3qkzENRwngek4+ilmB3ZuLO2QMVY3sieMyIgu8ZE1UqXTjnEMLuCM825L55Uk8A6h4jfugmfCZFmT25J5R6GOGE6jFd9KS7fWru7PSaU6KP16YZG810g1ocohrRZyM5+dPxihZkfqPX1668= On 7/21/05, Mike Smith <drivers(a)mu.org> wrote: > > > On Jul 20, 2005, at 5:24 PM, Herb Petschauer wrote: > > Under Panther, I can see that in this scenario, current_task() == > p->task. I can't see why that wouldn't always be true (in this > scenario, I need to do more code reading for a better blanket > statement and it's not really important at the moment). Is it safe to > just port my ioctl callback routine to use current_task() for both > Tiger and Panther? > In a general sense, no. You should use the proc out of the vfs_context_t > and fetch its task; this is the mechanism by which proxy work is enabled. > > However, if you're in the ioctl handler there is AFAIK no way to be called > except on the requester's task, so you're probably safe. > > If you have a vfs_context_t to hand, you can sanity-check the context's proc > against current_proc() just to be sure; if the two don't match then > something > odd is going on. > > = Mike > Yes, I did some more code reading before going on a few days vacation. In the general case I'd never assume current_task() == p->task :-) Thanks for the added info (the Panther verision current asserts current_task() == p->task and so far so good apparently) and another sanity assert... Cheers! H. _______________________________________________ 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: Mac OS 10.4 (Tiger) compilation errors ( GCC v3.3 ) with X Code 2.0 tool
by Josh Graessley 26 Jul '05

26 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com -josh On Jul 25, 2005, at 10:48 PM, Karunakar Reddy G wrote: Hi Josh, For that I need to update mbuf_t for hardware checks. 1) mbuf->m_pkthdr.csum_flags = 0x0020; 2) mbuf->m_pkthdr.csum_data = 0xFFFFFFFF; Thanks Karunakar _______________________________________________ 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 I'm not sure I follow. I understand that you set that flag and value on the outbound path. Who is the client of that flag and value? The csum_flags value of 0x0020 is undefined. I use this to update checksum flag and data for Transmits an output packet , I override function outputPacket(mbuf _t, void * param) which defined in "network/IONetworkController.h", In old code, it can be used very easily using mbuf->m_pkthdr, You can see below for the same, now I dont have any option to update these members I will appreciate if any body can help me, /* record/packet header in first mbuf of chain; valid if M_PKTHDR set */ struct pkthdr { int len; /* total packet length */ struct ifnet *rcvif; /* rcv interface */ /* variables for ip and tcp reassembly */ void *header; /* pointer to packet header */ /* variables for hardware checksum */ int csum_flags; /* flags regarding checksum */ int csum_data; /* data field used by csum routines */ struct mbuf *aux; /* extra data buffer; ipsec/others */ void *reserved1; /* for future use */ void *reserved2; /* for future use */ }; _______________________________________________ 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/jgraessley% 40apple.com This email sent to jgraessley(a)apple.com smime.p7s

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Re: sock_receive_internal() and its (ab)use of uio
by Josh Graessley 26 Jul '05

26 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Jul 25, 2005, at 6:08 PM, Sam Vaughan wrote: <snip> -josh _______________________________________________ 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 Out of curiosity, I thought that one of the motivators for the KPI was to give you the ability to make more changes in point releases of the OS. The KPI should permit you to change the contents of struct socket, let alone to just add another KPI entry point in kpi_socket.[ch]. Or, to put it another way, if you guys aren't going to make big changes to the KPI in minor releases, what's stopping us from linking to mach_kernel and overwriting our Info.plist's com.apple.kernel entry with the output of `uname -r` before loading our kext? ;o) We don't have a good way to deliver new headers with software updates. No header means no prototype or documentation for the new function. The motivation of the KPI is to give us the freedom to fix bugs, add features, and improve performance without breaking third party kexts. The whole point of the KPI is that we can make big changes internally without making any change to the KPI. We don't want to go crazy and have a dozen ways to do everything. The more functions we supply, the more we have to maintain and the more limits we have on the changes we can make in the future. We have to balance requests for everything every developer ever asks for with our need to have a clear, coherent, lightweight, and easily maintainable interface for developers. Radar is the right place to make requests for missing functionality or report a bug with the current implementation. There are a variety of reasons not to use uname -r as you suggest above. I would hope the thing that stops most developers is their interest in shipping a robust, quality product to their customers. When you are writing kernel code, you need to be careful. If you link directly against the kernel, you are probably doing it because you're doing something skanky. Some day, when some assumption you are making breaks, your customer will suffer. All the finger pointing in the world won't bring back the lost productivity and data. If we don't work together, the end user suffers. smime.p7s

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Re: Mac OS 10.4 (Tiger) compilation errors ( GCC v3.3 ) with X Code 2.0 tool
by Karunakar Reddy G 26 Jul '05

26 Jul '05

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:reply-to:to:subject:in-reply-to:mime-version:content-type:references; b=o2sfrX3aGnRAfhEMKzdk8z/Ibbmfa7oxKdToY5hTCsHPA+bkt8QCUS2rA4dCHnviGec2Sq6HbPLCnbLJrBfFUEUVIuAE4IhfvpfCAjvvwbDPGIQRcjPbjcV6NnhmUrsos8YKiJyfrZeWdEGGiu47FKKBtjtNqeJLF26/fa5Bmlk= _______________________________________________ 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: sock_receive_internal() and its (ab)use of uio
by Sam Vaughan 26 Jul '05

26 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Sam On 26/07/2005, at 10:33 AM, Josh Graessley wrote: Hi Sam, Thanks, -josh _______________________________________________ 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.… You're right, Josh, I don't need to allocate another uio, but I do need to allocate more memory for iovecs, despite already having some perfectly good ones of my own. I suppose the crux of it is that the msghdr interface is half-way to the usefulness of uio. If it only allowed you to specify one address and length then I probably would have just coded to it and forgotten about it straight away. I understand your position though. Evidently the majority of people using your KPI are writing to it from scratch rather than building a common code base that runs in the kernels of several OSes. It'd be hard to imagine anyone not using uio structures if they were also targetting other UNIX platforms. Out of curiosity, I thought that one of the motivators for the KPI was to give you the ability to make more changes in point releases of the OS. The KPI should permit you to change the contents of struct socket, let alone to just add another KPI entry point in kpi_socket. [ch]. Or, to put it another way, if you guys aren't going to make big changes to the KPI in minor releases, what's stopping us from linking to mach_kernel and overwriting our Info.plist's com.apple.kernel entry with the output of `uname -r` before loading our kext? ;o) You don't need to allocate another uio. You just need to allocate some iovecs. The uio is handy for you because you happened to have a uio available for other reasons. When we looked at what most kexts were doing, we found that 90+% of them had to allocate and fill out a uio just to send some data. We wanted to make it easier by dealing with the uio so the kext developer didn't have to worry about that. Your request is the first we have received for a uio variant. There are probably more developers frustrated that they have to fill out an iovec array to describe their data instead of passing a pointer and length. We will not be able to add a uio variant in a software update (10.4.x). This means you would need to wait for the next major release at the earliest for such a function. Since you will have to work around this problem to support 10.4.x, I'm not sure it makes a lot of sense to add this function. If we hear more requests for a uio variant of the send and receive functions, I will look in to getting those in. This email sent to site_archiver(a)lists.apple.com

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Re: vmmap on a 64-bit application
by Justin C. Walker 26 Jul '05

26 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Jul 25, 2005, at 17:50 , Mathew, Ashok wrote: This is the correct list to discuss it... Running vmmap on a 64-bit application gives a segmentation fault on my system which is running 10.4.2. Has anyone tried running vmmap to a 64-bit application ? Does anyone have any info on this ? No info; just a confirmation that I see the same thing. Regards, Justin -- Justin C. Walker, Curmudgeon-At-Large Institute for General Semantics -------- It's not whether you win or lose... It's whether *I* win or lose. -------- _______________________________________________ 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.… Not sure if this is the correct list to post this but anyway ... [snip] You should file a bug report (http://bugreporter.apple.com) This list isn't a path to Apple (you may already know this; I mention it just in case). This email sent to site_archiver(a)lists.apple.com

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vmmap on a 64-bit application
by Mathew, Ashok 26 Jul '05

26 Jul '05

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: AcWQ7sQgs6XSBAFuQOeO4bJsctWVcAAfAJaQ Thread-topic: vmmap on a 64-bit application Not sure if this is the correct list to post this but anyway ... Running vmmap on a 64-bit application gives a segmentation fault on my system which is running 10.4.2. Darwin host-9.local 8.2.0 Darwin Kernel Version 8.2.0: Fri Jun 24 17:46:54 PDT 2 005; root:xnu-792.2.4.obj~3/RELEASE_PPC Power Macintosh powerpc Has anyone tried running vmmap to a 64-bit application ? Does anyone have any info on this ? Thanks, -Ashok, _______________________________________________ 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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