From 0648a07c9b22acc33ead0645cf8f607b0c9c7e32 Mon Sep 17 00:00:00 2001 From: Artem Savkov Date: Sat, 20 May 2017 09:58:10 +0200 Subject: scsi: scsi_dh_rdac: Use ctlr directly in rdac_failover_get() rdac_failover_get references struct rdac_controller as ctlr->ms_sdev->handler_data->ctlr for no apparent reason. Besides being inefficient this also introduces a null-pointer dereference as send_mode_select() sets ctlr->ms_sdev to NULL before calling rdac_failover_get(): [ 18.432550] device-mapper: multipath service-time: version 0.3.0 loaded [ 18.436124] BUG: unable to handle kernel NULL pointer dereference at 0000000000000790 [ 18.436129] IP: send_mode_select+0xca/0x560 [ 18.436129] PGD 0 [ 18.436130] P4D 0 [ 18.436130] [ 18.436132] Oops: 0000 [#1] SMP [ 18.436133] Modules linked in: dm_service_time sd_mod dm_multipath amdkfd amd_iommu_v2 radeon(+) i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm qla2xxx drm serio_raw scsi_transport_fc bnx2 i2c_core dm_mirror dm_region_hash dm_log dm_mod [ 18.436143] CPU: 4 PID: 443 Comm: kworker/u16:2 Not tainted 4.12.0-rc1.1.el7.test.x86_64 #1 [ 18.436144] Hardware name: IBM BladeCenter LS22 -[79013SG]-/Server Blade, BIOS -[L8E164AUS-1.07]- 05/25/2011 [ 18.436145] Workqueue: kmpath_rdacd send_mode_select [ 18.436146] task: ffff880225116a40 task.stack: ffffc90002bd8000 [ 18.436148] RIP: 0010:send_mode_select+0xca/0x560 [ 18.436148] RSP: 0018:ffffc90002bdbda8 EFLAGS: 00010246 [ 18.436149] RAX: 0000000000000000 RBX: ffffc90002bdbe08 RCX: ffff88017ef04a80 [ 18.436150] RDX: ffffc90002bdbe08 RSI: ffff88017ef04a80 RDI: ffff8802248e4388 [ 18.436151] RBP: ffffc90002bdbe48 R08: 0000000000000000 R09: ffffffff81c104c0 [ 18.436151] R10: 00000000000001ff R11: 000000000000035a R12: ffffc90002bdbdd8 [ 18.436152] R13: ffff8802248e4390 R14: ffff880225152800 R15: ffff8802248e4400 [ 18.436153] FS: 0000000000000000(0000) GS:ffff880227d00000(0000) knlGS:0000000000000000 [ 18.436154] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 18.436154] CR2: 0000000000000790 CR3: 000000042535b000 CR4: 00000000000006e0 [ 18.436155] Call Trace: [ 18.436159] ? rdac_activate+0x14e/0x150 [ 18.436161] ? refcount_dec_and_test+0x11/0x20 [ 18.436162] ? kobject_put+0x1c/0x50 [ 18.436165] ? scsi_dh_activate+0x6f/0xd0 [ 18.436168] process_one_work+0x149/0x360 [ 18.436170] worker_thread+0x4d/0x3c0 [ 18.436172] kthread+0x109/0x140 [ 18.436173] ? rescuer_thread+0x380/0x380 [ 18.436174] ? kthread_park+0x60/0x60 [ 18.436176] ret_from_fork+0x2c/0x40 [ 18.436177] Code: 49 c7 46 20 00 00 00 00 4c 89 ef c6 07 00 0f 1f 40 00 45 31 ed c7 45 b0 05 00 00 00 44 89 6d b4 4d 89 f5 4c 8b 75 a8 49 8b 45 20 <48> 8b b0 90 07 00 00 48 8b 56 10 8b 42 10 48 8d 7a 28 85 c0 0f [ 18.436192] RIP: send_mode_select+0xca/0x560 RSP: ffffc90002bdbda8 [ 18.436192] CR2: 0000000000000790 [ 18.436198] ---[ end trace 40f3e4dca1ffabdd ]--- [ 18.436199] Kernel panic - not syncing: Fatal exception [ 18.436222] Kernel Offset: disabled [-- MARK -- Thu May 18 11:45:00 2017] Fixes: 327825574132 scsi_dh_rdac: switch to scsi_execute_req_flags() Cc: stable@vger.kernel.org Signed-off-by: Artem Savkov Reviewed-by: Christoph Hellwig Signed-off-by: Martin K. Petersen --- drivers/scsi/device_handler/scsi_dh_rdac.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c index 3cbab8710e58..2ceff585f189 100644 --- a/drivers/scsi/device_handler/scsi_dh_rdac.c +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c @@ -265,18 +265,16 @@ static unsigned int rdac_failover_get(struct rdac_controller *ctlr, struct list_head *list, unsigned char *cdb) { - struct scsi_device *sdev = ctlr->ms_sdev; - struct rdac_dh_data *h = sdev->handler_data; struct rdac_mode_common *common; unsigned data_size; struct rdac_queue_data *qdata; u8 *lun_table; - if (h->ctlr->use_ms10) { + if (ctlr->use_ms10) { struct rdac_pg_expanded *rdac_pg; data_size = sizeof(struct rdac_pg_expanded); - rdac_pg = &h->ctlr->mode_select.expanded; + rdac_pg = &ctlr->mode_select.expanded; memset(rdac_pg, 0, data_size); common = &rdac_pg->common; rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40; @@ -288,7 +286,7 @@ static unsigned int rdac_failover_get(struct rdac_controller *ctlr, struct rdac_pg_legacy *rdac_pg; data_size = sizeof(struct rdac_pg_legacy); - rdac_pg = &h->ctlr->mode_select.legacy; + rdac_pg = &ctlr->mode_select.legacy; memset(rdac_pg, 0, data_size); common = &rdac_pg->common; rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER; @@ -304,7 +302,7 @@ static unsigned int rdac_failover_get(struct rdac_controller *ctlr, } /* Prepare the command. */ - if (h->ctlr->use_ms10) { + if (ctlr->use_ms10) { cdb[0] = MODE_SELECT_10; cdb[7] = data_size >> 8; cdb[8] = data_size & 0xff; -- cgit v1.2.3