On Friday, 29 June 2007 17:28, Keshavamurthy, Anil S wrote: > On Thu, Jun 28, 2007 at 06:14:27PM -0700, Li, Shaohua wrote: > > > > > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.22- > > >rc6/2.6.22-rc6-mm1/ > > >> > > >>> +intel-iommu-dmar-detection-and-parsing-logic.patch > [..] > > > > > >I took a picture of it, looks like the backtrace is: > > > > > >NULL pointer dereference at 024 > > >EIP:dmar_table_init+0x11 > > >intel_iommu_init+0x30 > > >pci_iommu_init+0xe > > >kernel_init+0x16e > > > > > >Presumably something is NULL in dmar_table_init that wasn't expected to > > >be.. I would guess it likely crashes on any system without an Intel > > >IOMMU in it. > Yup, that is correct. > > > How about something like below? > > > > > > int __init dmar_table_init(void) > > { > > + if (!dmar_tbl) > > + return -ENODEV; > > parse_dmar_table(); > why not check for NULL in the function where it touched? > Also when there are no DMAR devices we need the below > printk on the console. > > > if (list_empty(&dmar_drhd_units)) { > > printk(KERN_ERR PREFIX "No DMAR devices found\n"); > > return -ENODEV; > > } > > return 0; > > } > > Here is the revised patch of the above. > Andrew, please add this fix to > +intel-iommu-dmar-detection-and-parsing-logic.patch > ------------------------------------------------ > > Check for dmar_tbl pointer as this can be NULL on > systems with no Intel VT-d support. > > Signed-off-by: Anil S Keshavamurthy <[EMAIL PROTECTED]>
For the record, this patch fixes the boot crash on my AMD64-based test box. Thanks, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
