Date: Mon, 14 Feb 2011 13:58:44 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-current@freebsd.org, Matthew Fleming <mdf356@gmail.com> Subject: Re: acpi_resource bug? Message-ID: <201102141358.45583.jkim@FreeBSD.org> In-Reply-To: <201102141337.59203.jhb@freebsd.org> References: <AANLkTi=C31iGJMonj7E3DGLWhx0cSKQR=b7ZHTv9CdmA@mail.gmail.com> <201102141330.20330.jkim@FreeBSD.org> <201102141337.59203.jhb@freebsd.org>
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On Monday 14 February 2011 01:37 pm, John Baldwin wrote: > On Monday, February 14, 2011 1:30:18 pm Jung-uk Kim wrote: > > On Monday 14 February 2011 10:29 am, Matthew Fleming wrote: > > > On Mon, Feb 14, 2011 at 6:24 AM, John Baldwin <jhb@freebsd.org> > > > > wrote: > > > > On Sunday, February 13, 2011 2:46:07 pm Matthew Fleming wrote: > > > >> I'm not very familiar with the acpi code, but we have seen > > > >> an intermittent issue on boot: > > > >> > > > >> 1) should the length of the bcopy() be changed to either > > > >> respect res->Length or the actual length of the > > > >> ACPI_RESOURCE_DATA for the type? > > > > > > > > It should just use res->Length: > > > > > > Is there a guarantee that res->Length is <= > > > sizeof(ACPI_RESOURCE) ? > > > > No. Please try the attached patch (after your r218685). > > I think your patch is correct, but are you saying that ACPICA will > return a resource with a size that doesn't match its type? > > ACPI_RESOURCE_DATA is a union of all the various resource types, > and it does contain both ACPI_RESOURCE_IRQ and > ACPI_RESOURCE_EXTENDED_IRQ, so it's hard to see how res->Length > would be greater than the size of ACPI_RESOURCE. Some resource type has variable size. For example, ACPI_RESOURCE_EXTENDED_IRQ has ACPI_RESOURCE_SOURCE field, which has a pointer to string and Length field will include length of the string (+ 1 for null terminator). Also, the Length only includes the ACPI_RESOURCE_DATA, not the header itself, etc. Jung-uk Kim
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