0648a07c9b
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 <asavkov@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.