Date: Fri, 01 Nov 2002 16:37:22 +0100 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: current@freebsd.org Subject: Re: cvs commit: src/sys/fs/specfs spec_vnops.c Message-ID: <95735.1036165042@critter.freebsd.dk> In-Reply-To: Your message of "Fri, 01 Nov 2002 07:32:12 PST." <200211011532.gA1FWCA4017922@repoman.freebsd.org>
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In message <200211011532.gA1FWCA4017922@repoman.freebsd.org>, Poul-Henning Kamp
writes:
>phk 2002/11/01 07:32:12 PST
>
> Modified files:
> sys/fs/specfs spec_vnops.c
> Log:
> Put a KASSERT in specfs::strategy() to check that the incoming buffer
> has a valid b_iocmd. Valid is any one of BIO_{READ,WRITE,DELETE}.
>
> I have seen at least one case where the bio_cmd field was zero once the
> request made it into GEOM. Putting the KASSERT here allows us to spot
> the culprit in the backtrace.
If any of you encounter this panic ("Wrong b_iocmd buf...") please
try to capture a traceback and mail it to me.
This is likely connected to the problems Kirk are debugging right now
and may be responsible for some of the weirder Heisenbugs people have
reported.
Worst case, (before this commit) it could result in a read request
being carried out as a write request by a disk device driver.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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