Currently the back pointer from a queue to the vhost adapter isn't set until after subcrq interrupt registration. The value is available when a queue is first allocated and can/should be also set for primary and async queues as well as subcrqs. This fixes a crash observed during kexec/kdump on Power 9 with legacy XICS interrupt controller where a pending subcrq interrupt from the previous kernel can be replayed immediately upon IRQ registration resulting in dereference of a garbage backpointer in ibmvfc_interrupt_scsi(). Kernel attempted to read user page (58) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x00000058 Faulting instruction address: 0xc008000003216a08 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c008000003216a08] ibmvfc_interrupt_scsi+0x40/0xb0 [ibmvfc] LR [c0000000082079e8] __handle_irq_event_percpu+0x98/0x270 Call Trace: [c000000047fa3d80] [c0000000123e6180] 0xc0000000123e6180 (unreliable) [c000000047fa3df0] [c0000000082079e8] __handle_irq_event_percpu+0x98/0x270 [c000000047fa3ea0] [c000000008207d18] handle_irq_event+0x98/0x188 [c000000047fa3ef0] [c00000000820f564] handle_fasteoi_irq+0xc4/0x310 [c000000047fa3f40] [c000000008205c60] generic_handle_irq+0x50/0x80 [c000000047fa3f60] [c000000008015c40] __do_irq+0x70/0x1a0 [c000000047fa3f90] [c000000008016d7c] __do_IRQ+0x9c/0x130 [c000000014622f60] [0000000020000000] 0x20000000 [c000000014622ff0] [c000000008016e50] do_IRQ+0x40/0xa0 [c000000014623020] [c000000008017044] replay_soft_interrupts+0x194/0x2f0 [c000000014623210] [c0000000080172a8] arch_local_irq_restore+0x108/0x170 [c000000014623240] [c000000008eb1008] _raw_spin_unlock_irqrestore+0x58/0xb0 [c000000014623270] [c00000000820b12c] __setup_irq+0x49c/0x9f0 [c000000014623310] [c00000000820b7c0] request_threaded_irq+0x140/0x230 [c000000014623380] [c008000003212a50] ibmvfc_register_scsi_channel+0x1e8/0x2f0 [ibmvfc] [c000000014623450] [c008000003213d1c] ibmvfc_init_sub_crqs+0xc4/0x1f0 [ibmvfc] [c0000000146234d0] [c0080000032145a8] ibmvfc_reset_crq+0x150/0x210 [ibmvfc] [c000000014623550] [c0080000032147c8] ibmvfc_init_crq+0x160/0x280 [ibmvfc] [c0000000146235f0] [c00800000321a9cc] ibmvfc_probe+0x2a4/0x530 [ibmvfc]
Unified · Split
| @@ -5682,6 +5682,8 @@ static int ibmvfc_alloc_queue(struct ibmvfc_host *vhost, · 5681 unmodified lines | |||
| 5682 | queue->cur = 0; | 5682 | queue->cur = 0; |
| 5683 | queue->fmt = fmt; | 5683 | queue->fmt = fmt; |
| 5684 | queue->size = PAGE_SIZE / fmt_size; | 5684 | queue->size = PAGE_SIZE / fmt_size; |
| 5685 | |||
| 5686 | queue->vhost = vhost; | ||
| 5685 | return 0; | 5687 | return 0; |
| 5686 | } | 5688 | } |
| 5687 | 5689 | ||
| @@ -5787,7 +5789,6 @@ static int ibmvfc_register_scsi_channel(struct ibmvfc_host *vhost, · 99 unmodified lines | |||
| 5787 | } | 5789 | } |
| 5788 | 5790 | ||
| 5789 | scrq->hwq_id = index; | 5791 | scrq->hwq_id = index; |
| 5790 | scrq->vhost = vhost; | ||
| 5791 | 5792 | ||
| 5792 | LEAVE; | 5793 | LEAVE; |
| 5793 | return 0; | 5794 | return 0; |
| @@ -789,6 +789,7 @@ struct ibmvfc_queue { · 788 unmodified lines | |||
| 789 | spinlock_t _lock; | 789 | spinlock_t _lock; |
| 790 | spinlock_t *q_lock; | 790 | spinlock_t *q_lock; |
| 791 | 791 | ||
| 792 | struct ibmvfc_host *vhost; | ||
| 792 | struct ibmvfc_event_pool evt_pool; | 793 | struct ibmvfc_event_pool evt_pool; |
| 793 | struct list_head sent; | 794 | struct list_head sent; |
| 794 | struct list_head free; | 795 | struct list_head free; |
| @@ -797,7 +798,6 @@ struct ibmvfc_queue { · 2 unmodified lines | |||
| 797 | union ibmvfc_iu cancel_rsp; | 798 | union ibmvfc_iu cancel_rsp; |
| 798 | 799 | ||
| 799 | /* Sub-CRQ fields */ | 800 | /* Sub-CRQ fields */ |
| 800 | struct ibmvfc_host *vhost; | ||
| 801 | unsigned long cookie; | 801 | unsigned long cookie; |
| 802 | unsigned long vios_cookie; | 802 | unsigned long vios_cookie; |
| 803 | unsigned long hw_irq; | 803 | unsigned long hw_irq; |