Date: Mon, 8 Jul 2002 16:40:03 -0700 (PDT) From: Bruce Evans <bde@zeta.org.au> To: freebsd-bugs@FreeBSD.org Subject: Re: i386/40354: crash, whith floating ops in kernel mode Message-ID: <200207082340.g68Ne3Yx024884@freefall.freebsd.org>
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The following reply was made to PR i386/40354; it has been noted by GNATS. From: Bruce Evans <bde@zeta.org.au> To: unicorn@forest.od.ua Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: i386/40354: crash, whith floating ops in kernel mode Date: Tue, 9 Jul 2002 09:38:38 +1000 (EST) On Mon, 8 Jul 2002 unicorn@forest.od.ua wrote: > >Description: > npx dna handler tries to modify curpcb even if it does not exist (yet). > it couses page fault in kernel mode. curpcb is supposed to always exist if the npx dna handler is called. > >How-To-Repeat: > do some floating point operations before the first process created. Don't do that. Normal floating point operations are only supported for user processes (*). The kernel does some FP initializations, but it is supposed to be careful to call stop_emulating() before it does them so that an npx dna exception doesn't occur. (*) FP is close to working or working in kernel processes, but this is not supported. FP is used in i586_bcopy() and i586_bzero(), but these are broken and not used in -current. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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