Red Hat Bugzilla – Bug 116766
IDE CD DMA + 4GB ia32e box == instant panic
Last modified: 2015-01-04 17:04:42 EST
This is with kernel-2.6.3-1.104.
Booting the kernel and then accessing the CD (mount, checkisomd5) with
DMA gives an immediate panic, with a backtrace of:
mark_clean + 172, pci_unmap_sg + 68, ide_destroy_dmatable + 42,
__ide_dma_end + 101, ide_cd:cdrom_read_intr:74
Booting with mem=4096M works OK.
DMA HD access works OK.
hdparm -d0 /dev/hdc causes it to then work OK.
Works in 2.4, FWIW.
did this get fixed ?
Appears to have been.
Mounting a CD fails, says it can't read the filesystem.
chkisomd5sum on the CD device panics.
Created attachment 101992 [details]
Patch fixing the issue
With swiotlb, pci_unmap_sg() was doing pci_unmap_single() instead of
swiotlb_unmap_sg(). This will fail because, swiotlb_map_sg() is
setting up virtual address in sg->dma_address and pci_unmap_single()
expects physical address.
Attached patch will fix the issue.
This issue is fixed in the base sometime back. Sorry forgot to update
Yeah, haven't seen this recently.