Date: Wed, 18 Feb 2004 17:44:00 +0100 From: Andreas Kohn <andreas.kohn@gmx.net> To: Daniel Papasian <dpapasia@andrew.cmu.edu> Cc: current@FreeBSD.org Subject: Re: [PANIC] page fault -> bremfree: removing a buffer not on a queue Message-ID: <1077122639.794.21.camel@klamath.syndrom23.de> In-Reply-To: <Pine.BSF.4.58-036.0402181020280.4492@damnleftist.res.cmu.edu> References: <1077099032.1231.12.camel@klamath.syndrom23.de> <Pine.BSF.4.58-036.0402181020280.4492@damnleftist.res.cmu.edu>
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--=-R9JWetPgI5D9Hf4e1UOF Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hello, Thank you for your reply! On Wed, 2004-02-18 at 16:28, Daniel Papasian wrote: > On Wed, 18 Feb 2004, Andreas Kohn wrote: > > Hello, > > > > yesterday my computer crashed with this panic: > > > <snip> > > > > syncing disks, buffers remaining... panic: bremfree: removing a buffer > > not on a queue >=20 > Okay, I'm not the only one who has had this panic. I've been looking at > it, but without essentially zero prior knowledge of the filesystem and no > computer around with a filesystem I can afford to have corrupted, > personally I'm afraid to take any sort of action. /me too. Until I have a proper backup I don't think I will try to push that box too hard. >=20 > > Before the panic happened, I was compiling/linking some software, and > > watching TV (bttv/xawtv). The linking process gave some strange error >=20 > My question is, did you do this on a "dirty" filesystem using > softupdates- that is, one that crashed and came up and fsck was in the > process of reclaiming unused resources? >=20 No, at least I don't think so. I do have occasional panics with bgfsck afterwards, but in this case the box was running for some hours, so there shouldn't have been any fsck activity. Most of the panics I get seem to relate to disk activity + xawtv running, although I hadn't had any spare time to try to find the cause yet. > I believe the easiest solution is to test in bremfree whether there are > less than or equal to 1 locks (BUF_REFCNT) on the buffer and if there > aren't, simply return. But by no means do I believe this solution to be > correct; bremfree should not be called if this is the case, I suspect, bu= t > it is being called in such circumstances in more than one place (my > crashdump, posted earlier to current@, called bremfree at a different > place) >=20 > Unless, of course, the if(BUF_REFCNT(bp) <=3D1) assertion inside of > bremfreel is not correct. >=20 I didn't look deeper into the sources yet, but perhaps someone else can comment on this? > -Dan >=20 Regards, Andreas --=-R9JWetPgI5D9Hf4e1UOF Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQBAM5ZPYucd7Ow1ygwRAilIAKCYBuRGTwjKf0kAs62UlQzWYDOORQCeMceV igJCnkrJE4mOOCUJHaVY3+E= =u4mm -----END PGP SIGNATURE----- --=-R9JWetPgI5D9Hf4e1UOF--
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