From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Wilck Date: Mon, 06 Aug 2001 12:30:08 +0000 Subject: Re: [Linux-ia64] Kernel BUG report Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Fri, 3 Aug 2001, Van Maren, Kevin wrote: > This is in __free_pages_ok: > if (page->mapping) > => BUG(); It's hard to see a connection between this problem and the one you report below. > 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. 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 ? > 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. 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 FSC EP PS DS1, Paderborn Tel. +49 5251 8 15113