July 2004 - Darwin-kernel - lists.apple.com

Re: infinite loop in ffs_sync()
by Nikita Danilov 27 Jul '04

27 Jul '04

Brian Bergstrand writes: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > In theory, this is a bug, but in practice, it won't be a problem. This > is because all simple_lock ops are noops in all currently shipping > kernels. They are all defined out in <sys/lock.h>. I found a deadlock > in vget() over a year ago that I reported (#3193564) and it was closed > as "Behaves Correctly" for this same reason. Darwin VFS's current > position is "the funnel protects all". Sorry, seems I was too vague in my description of what happens here. Suppose that first vnode in the mnt_vnodelist (that is mp->mnt_vnodelist.lh_first), is detached from mount-point (vp->v_mount != mp), then ffs_sync() will obviously loop indefinitely, right? The only reason I mentioned simple_lock is to indicate that other CPU cannot remove vnode from the mnt_vnodelist, hence, breaking the loop. Things remain the same even if, as you say, all VFS data are protected by the funnel. > > On Jul 27, 2004, at 6:28 AM, Nikita Danilov wrote: > > > Hello, > > > > xnu/bsd/ufs/ffs/ffs_vfsops.c:ffs_sync() contains > > > > ---------------------------------------------------------------------- > > /* > > * Write back each (modified) inode. > > */ > > simple_lock(&mntvnode_slock); > > loop: > > for (vp = mp->mnt_vnodelist.lh_first; > > vp != NULL; > > vp = nvp) { > > int didhold = 0; > > > > /* > > * If the vnode that we are about to sync is no longer > > * associated with this mount point, start over. > > */ > > if (vp->v_mount != mp) > > goto loop; > > ---------------------------------------------------------------------- Nikita. _______________________________________________ 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: infinite loop in ffs_sync()
by Brian Bergstrand 27 Jul '04

27 Jul '04

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 In theory, this is a bug, but in practice, it won't be a problem. This is because all simple_lock ops are noops in all currently shipping kernels. They are all defined out in <sys/lock.h>. I found a deadlock in vget() over a year ago that I reported (#3193564) and it was closed as "Behaves Correctly" for this same reason. Darwin VFS's current position is "the funnel protects all". On Jul 27, 2004, at 6:28 AM, Nikita Danilov wrote: > Hello, > > xnu/bsd/ufs/ffs/ffs_vfsops.c:ffs_sync() contains > > ---------------------------------------------------------------------- > /* > * Write back each (modified) inode. > */ > simple_lock(&mntvnode_slock); > loop: > for (vp = mp->mnt_vnodelist.lh_first; > vp != NULL; > vp = nvp) { > int didhold = 0; > > /* > * If the vnode that we are about to sync is no longer > * associated with this mount point, start over. > */ > if (vp->v_mount != mp) > goto loop; > ---------------------------------------------------------------------- > > As mp->mnt_vnodelist is protected by mntvnode_slock lock, which is not > released here, offending vnode cannot be removed from the list, and > goto > loop is infinite. > > Exactly the same bug was present in the ffs_vfsops.c:1.232 (Fri Apr 30 > 23:14:30 2004) version of this file in FreeBSD, but is fixed in FreeBSD > HEAD. > Brian Bergstrand <http://www.bergstrand.org/brian/>, AIM: triryche206 PGP Key: <http://www.bergstrand.org/brian/misc/public_key.txt> There are no innocents in a world with the F.B.I. and Carnivore. - U.F. 000802 As of 10:02:03 AM, iTunes is playing "Let You Down" from "Three Days Grace" by "Three Days Grace" -----BEGIN PGP SIGNATURE----- Version: PGP 8.1 iQA+AwUBQQZgpHnR2Fu2x7aiEQJTNQCY72ZSpQ86YM44XtWiIw/5GVS0WQCg016O iLB3KDphNlk/flSwotVFKf0= =m2c0 -----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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Re: Darwin Developers
by Exinos Technologies 27 Jul '04

27 Jul '04

Hello I am sure there are many talented people are working on the Darwin Kernel inside and outside of Apple, and hopefully some will be interested. Without going in to too much detail, we are interested in developing a system similar to FreeBSD's "Jail" for Darwin/OS X... Would be interested to know if there is any interest in this? Maybe there is something going on already by another company in this area? Thank you -- Mazdak Rezvani T: 416.857.3297 F: 416.352.5279 www.exinos.com The information in this email is confidential and is intended solely for the addressee(s). Access to this email by anyone else is unauthorized. If you are not an intended recipient, you must not read, use or disseminate the information contained in the email. On Jul 27, 2004, at 10:34 AM, Shawn Erickson wrote: On Jul 27, 2004, at 4:58 AM, Exinos Technologies wrote: Hello Forgive me if this is the wrong forum to be asking this question, but I don't know where else to begin... I am looking to start a Mac OS X/Darwin Kernel project but having a hard time finding freelance or otherwise developers with expertise in the Darwin kernel. Any guidance in this area would be appreciated. Many kernel capable developers are lurking on this list and other Apple provided ones. Additionally many folks are on lists related to OpenDarwin (visit opendarwin.org and likely their "hacker" list). What type of project are you trying to do? If you are trying to get someone interested you may want to post that kind of information, etc. -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: Darwin Developers
by Shawn Erickson 27 Jul '04

27 Jul '04

On Jul 27, 2004, at 4:58 AM, Exinos Technologies wrote: Hello Forgive me if this is the wrong forum to be asking this question, but I don't know where else to begin... I am looking to start a Mac OS X/Darwin Kernel project but having a hard time finding freelance or otherwise developers with expertise in the Darwin kernel. Any guidance in this area would be appreciated. Many kernel capable developers are lurking on this list and other Apple provided ones. Additionally many folks are on lists related to OpenDarwin (visit opendarwin.org and likely their "hacker" list). What type of project are you trying to do? If you are trying to get someone interested you may want to post that kind of information, etc. -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: infinite loop in ffs_sync()
by Quinn 27 Jul '04

27 Jul '04

At 17:35 +0400 27/7/04, Nikita Danilov wrote: That's what I tried to do initially, but it doesn't support Mozilla. Hmmm. I just tried it with Mozilla 1.7 (Mac OS X version) and it worked fine. Weird. If you continue to have problems, please file a bug report about the bug reporter (-: You can do this by emailing the nice folks in our bug reporting group on <devbugs(a)apple.com>. I also filed it with bugzilla.opendarwin.org, bug 2088. Cool. S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Technical Support * Networking, Communications, Hardware _______________________________________________ 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: infinite loop in ffs_sync()
by Nikita Danilov 27 Jul '04

27 Jul '04

Quinn writes: > At 15:28 +0400 27/7/04, Nikita Danilov wrote: > >Subject: infinite loop in ffs_sync() > > No one at Apple has the job of monitoring this list and writing up > bug reports. We're all here on our spare time. So I'd appreciate it > if you could file this bug via the standard bug reporting system. > > <http://developer.apple.com/bugreporter/> That's what I tried to do initially, but it doesn't support Mozilla. I also filed it with bugzilla.opendarwin.org, bug 2088. Nikita. _______________________________________________ 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: debugging kernel paniced system
by Quinn 27 Jul '04

27 Jul '04

At 7:39 -0400 27/7/04, Andrew Gallatin wrote: Yes, that's how I found out about the crashdumps ;) Official documentation for this is coming soon. It's currently being reviewed. I expect to have it on the Apple developer web site next week. S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Technical Support * Networking, Communications, Hardware _______________________________________________ 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: infinite loop in ffs_sync()
by Quinn 27 Jul '04

27 Jul '04

At 15:28 +0400 27/7/04, Nikita Danilov wrote: Subject: infinite loop in ffs_sync() No one at Apple has the job of monitoring this list and writing up bug reports. We're all here on our spare time. So I'd appreciate it if you could file this bug via the standard bug reporting system. <http://developer.apple.com/bugreporter/> As an added benefit, if you file the bug yourself, you'll be able to track its progress. Thanks in advance -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Technical Support * Networking, Communications, Hardware _______________________________________________ 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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Darwin Developers
by Exinos Technologies 27 Jul '04

27 Jul '04

Hello Forgive me if this is the wrong forum to be asking this question, but I don't know where else to begin... I am looking to start a Mac OS X/Darwin Kernel project but having a hard time finding freelance or otherwise developers with expertise in the Darwin kernel. Any guidance in this area would be appreciated. Thanks -- Mazdak Rezvani T: 416.857.3297 F: 416.352.5279 www.exinos.com The information in this email is confidential and is intended solely for the addressee(s). Access to this email by anyone else is unauthorized. If you are not an intended recipient, you must not read, use or disseminate the information contained in the email. _______________________________________________ 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: Mac throws "Can't fork" after forking daemon a number of time s. W hats wrong ?
by Lassi A. Tuura 27 Jul '04

27 Jul '04

Hi, I don't really know anything about your actual problem, but thought I'd mention this: if ((pid = fork()) == 0) { execlp("pictwpstops", printer, argv[1], argv[2], argv[3], argv[4], argv[5], argv[6], NULL); return (errno); This probably doesn't do what you think it does. If the exec() fails for any reason, *both* the parent and the child processes will return, which is unlikely to be what you wanted. If fork() succeeds and exec() fails, normally you terminate all code paths with en exit() so that the child cannot survive. Theoretically this could cause the problems you see, but in practice that's unlikely as it would imply that the exec() call is failing rather often. You might want to log the error from exec() though so you will notice if this is happening. Lassi -- To be or not to be? --Shakespeare To do is to be. --Sartre Do be do be do! --Sinatra _______________________________________________ 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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