Kernel BUG report

I hit this running mkfs on a 8GB, 4X Lion running 4 mkfs processes, each on an 8-disk "md", with 8 disks on each of 4 Adaptec scsi channels [each md has 2 disks on each controller], with the boot disk on a separate adaptec controller; ql12160 unused.

Running the latest 2.4.7 IA64 patches, plus SGI's kernel profiling patches and the latest 6.20 adaptec driver from Justin Gibbs (people.freebsd.org/~gibbs/linux).

I had previously run that test with a couple "sync"s running in other vt logins and it ran (*very* slowly, hence the profiling).

  Kernel BUG at page_alloc.c: 75!
  Unable to handle kernel paging request at virtual address 0000000000000000
  mkfs.ext2[1582]: Oops 11003706212352

This is in __free_pages_ok:

	if (page->mapping)

=> BUG();

Unfortunatly I didn't write down more info before the machine was rebooted; looks like I'll have to set up a serial console.

I've also been getting a LOT (100's, not 10's) of these:
Warning - running *really* short on DMA buffers
which appear to be coming from the SCSI subsystem.

Update: I ran the "test" again, and I got a bunch more "short on DMA buffers"
messages, and then I got a bunch of lines like:
Segment 0xe000000228eb7840, blocks 2, addr 0x228eb13ff
followed by:

  Kernel panic:  Ththththaats all folks.  Too dangerous to continue.

Kevin

It's hard to see a connection between this problem and the one you report below.

This comes from the mid SCSI layer. I wonder if it's possible that there's still SCSI DMA memory shortage although the driver is capable of 39-bit addressing. We know that this driver is very hungry for buffers, especially if it has a lot of disks attached---However, with the new driver, SCSI memory should only be allocated for bookeeping such as scatter-gather lists, right? It might be worthwile to watch scsi_resize_dma_pool. In particular, I wonder whether

[l. 288 scsi_dma.c]

	/* limit DMA memory to 32MB: */
	new_dma_sectors = (new_dma_sectors + 15) & 0xfff0;

may be a problem with a very DMA-hungry driver ?

Weird - this happens if the number of requests in a scatter-gather list is incorrect. Again, doesn't look like a driver-related problem in the first place, unless the driver intentionally or unintentionally overwrites the scatter-gather data structures.

Have you informed Justin of the problem?
In any case, if you get more information, please keep me informed.

Martin

Martin Wilck     <[email protected]>
FSC EP PS DS1, Paderborn      Tel. +49 5251 8 15113