Benjamin Herrenschmidt wrote:
Hi ! Current -git as of today (that is 2.6.15-rc5 + the batch of fixes Linus pulled after his return) was dying in weird ways for me on POWER5. I had the good idea to activate slab debugging, and I now see it detecting slab corruption as soon as the IPR driver initializes.
Please try the attached patch. There appears to be a double free going on in the scsi scan code. There is a direct call to scsi_free_queue and then the following put_device calls the release function, which also frees the queue. Brian
Since I remember seeing a discussion somewhere on a list between Brian King and Jens Axboe about use-after-free problems in SCSI and possible other niceties of that sort, I though it might be related... Anything I can do to help track this down ? ipr: IBM Power RAID SCSI Device Driver version: 2.1.0 (October 31, 2005) ipr 0000:c0:01.0: Found IOA with IRQ: 99 ipr 0000:c0:01.0: Starting IOA initialization sequence. ipr 0000:c0:01.0: Adapter firmware version: 020A004E ipr 0000:c0:01.0: IOA initialized. scsi0 : IBM 570B Storage Adapter Slab corruption: start=c000000070de39a0, len=728 Redzone: 0x5a2cf071/0x5a2cf071. Last user: [<c0000000002297c4>](.blk_cleanup_queue+0xe4/0x170) 1d0: 6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 00 00 00 00 2b0: 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b Prev obj: start=c000000070de36b0, len=728 Redzone: 0x5a2cf071/0x5a2cf071. Last user: [<0000000000000000>](0x0) 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b Next obj: start=c000000070de3c90, len=728 Redzone: 0x170fc2a5/0x170fc2a5. Last user: [<c000000000227b00>](.blk_alloc_queue_node+0x30/0x90) Ben.
-- Brian King eServer Storage I/O IBM Linux Technology Center
Current scsi scanning code appears to have a use after free bug is a LLDD's slave_alloc fails. Remove the redundant scsi_free_queue. Signed-off-by: Brian King <brking@xxxxxxxxxx> --- drivers/scsi/scsi_scan.c | 1 - 1 files changed, 1 deletion(-) diff -puN drivers/scsi/scsi_scan.c~scsi_scan_use_after_free drivers/scsi/scsi_scan.c --- linux-2.6/drivers/scsi/scsi_scan.c~scsi_scan_use_after_free 2005-12-12 13:00:28.000000000 -0600 +++ linux-2.6-bjking1/drivers/scsi/scsi_scan.c 2005-12-12 13:00:28.000000000 -0600 @@ -279,7 +279,6 @@ static struct scsi_device *scsi_alloc_sd out_device_destroy: transport_destroy_device(&sdev->sdev_gendev); - scsi_free_queue(sdev->request_queue); put_device(&sdev->sdev_gendev); out: if (display_failure_msg) _
