From cc29a1b0a3f2597ce887d339222fa85b9307706d Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Tue, 8 Jan 2019 13:50:43 -0700 Subject: [PATCH] scsi: isci: initialize shost fully before calling scsi_add_host() scsi_mq_setup_tags(), which is called by scsi_add_host(), calculates the command size to allocate based on the prot_capabilities. In the isci driver, scsi_host_set_prot() is called after scsi_add_host() so the command size gets calculated to be smaller than it needs to be. Eventually, scsi_mq_init_request() locates the 'prot_sdb' after the command assuming it was sized correctly and a buffer overrun may occur. However, seeing blk_mq_alloc_rqs() rounds up to the nearest cache line size, the mistake can go unnoticed. The bug was noticed after the struct request size was reduced by commit 9d037ad707ed ("block: remove req->timeout_list") Which likely reduced the allocated space for the request by an entire cache line, enough that the overflow could be hit and it caused a panic, on boot, at: RIP: 0010:t10_pi_complete+0x77/0x1c0 Call Trace: sd_done+0xf5/0x340 scsi_finish_command+0xc3/0x120 blk_done_softirq+0x83/0xb0 __do_softirq+0xa1/0x2e6 irq_exit+0xbc/0xd0 call_function_single_interrupt+0xf/0x20 sd_done() would call scsi_prot_sg_count() which reads the number of entities in 'prot_sdb', but seeing 'prot_sdb' is located after the end of the allocated space it reads a garbage number and erroneously calls t10_pi_complete(). To prevent this, the calls to scsi_host_set_prot() are moved into isci_host_alloc() before the call to scsi_add_host(). Out of caution, also move the similar call to scsi_host_set_guard(). Fixes: 3d2d75254915 ("[SCSI] isci: T10 DIF support") Link: http://lkml.kernel.org/r/da851333-eadd-163a-8c78-e1f4ec5ec857@deltatee.com Signed-off-by: Logan Gunthorpe Cc: Intel SCU Linux support Cc: Artur Paszkiewicz Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Cc: Christoph Hellwig Cc: Jens Axboe Cc: Jeff Moyer Reviewed-by: Jeff Moyer Reviewed-by: Jens Axboe Signed-off-by: Martin K. Petersen --- drivers/scsi/isci/init.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/scsi/isci/init.c b/drivers/scsi/isci/init.c index 68b90c4f79a3..1727d0c71b12 100644 --- a/drivers/scsi/isci/init.c +++ b/drivers/scsi/isci/init.c @@ -576,6 +576,13 @@ static struct isci_host *isci_host_alloc(struct pci_dev *pdev, int id) shost->max_lun = ~0; shost->max_cmd_len = MAX_COMMAND_SIZE; + /* turn on DIF support */ + scsi_host_set_prot(shost, + SHOST_DIF_TYPE1_PROTECTION | + SHOST_DIF_TYPE2_PROTECTION | + SHOST_DIF_TYPE3_PROTECTION); + scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC); + err = scsi_add_host(shost, &pdev->dev); if (err) goto err_shost; @@ -663,13 +670,6 @@ static int isci_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) goto err_host_alloc; } pci_info->hosts[i] = h; - - /* turn on DIF support */ - scsi_host_set_prot(to_shost(h), - SHOST_DIF_TYPE1_PROTECTION | - SHOST_DIF_TYPE2_PROTECTION | - SHOST_DIF_TYPE3_PROTECTION); - scsi_host_set_guard(to_shost(h), SHOST_DIX_GUARD_CRC); } err = isci_setup_interrupts(pdev);