RDMA/umem: Add missing initialization of owning_mm

Artemy-Mellanox · jgunthorpe · commit a2093dd35f8c · 2019-01-25T09:55:48.000-07:00
When allocating a umem leaf for implicit ODP MR during page fault the field owning_mm was not set. Initialize and take a reference on this field to avoid kernel panic when trying to access this field. BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 PGD 800000022dfed067 P4D 800000022dfed067 PUD 22dfcf067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 634 Comm: kworker/u33:0 Not tainted 4.20.0-rc6+ torvalds#89 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 Workqueue: mlx5_ib_page_fault mlx5_ib_eqe_pf_action [mlx5_ib] RIP: 0010:ib_umem_odp_map_dma_pages+0xf3/0x710 [ib_core] Code: 45 c0 48 21 f3 48 89 75 b0 31 f6 4a 8d 04 33 48 89 45 a8 49 8b 44 24 60 48 8b 78 10 e8 66 16 a8 c5 49 8b 54 24 08 48 89 45 98 <8b> 42 58 85 c0 0f 84 8e 05 00 00 8d 48 01 48 8d 72 58 f0 0f b1 4a RSP: 0000:ffffb610813a7c20 EFLAGS: 00010202 RAX: ffff95ace6e8ac80 RBX: 0000000000000000 RCX: 000000000000000c RDX: 0000000000000000 RSI: 0000000000000850 RDI: ffff95aceaadae80 RBP: ffffb610813a7ce0 R08: 0000000000000000 R09: 0000000000080c77 R10: ffff95acfffdbd00 R11: 0000000000000000 R12: ffff95aceaa20a00 R13: 0000000000001000 R14: 0000000000001000 R15: 000000000000000c FS: 0000000000000000(0000) GS:ffff95acf7800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000058 CR3: 000000022c834001 CR4: 00000000001606f0 Call Trace: pagefault_single_data_segment+0x1df/0xc60 [mlx5_ib] mlx5_ib_eqe_pf_action+0x7bc/0xa70 [mlx5_ib] ? __switch_to+0xe1/0x470 process_one_work+0x174/0x390 worker_thread+0x4f/0x3e0 kthread+0x102/0x140 ? drain_workqueue+0x130/0x130 ? kthread_stop+0x110/0x110 ret_from_fork+0x1f/0x30 Fixes: f27a0d5 ("RDMA/umem: Use umem->owning_mm inside ODP") Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com> Signed-off-by: Moni Shoua <monis@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
@@ -352,6 +352,8 @@ struct ib_umem_odp *ib_alloc_odp_umem(struct ib_ucontext_per_mm *per_mm,
 	umem->writable   = 1;
 	umem->is_odp = 1;
 	odp_data->per_mm = per_mm;
+	umem->owning_mm  = per_mm->mm;
+	mmgrab(umem->owning_mm);
 
 	mutex_init(&odp_data->umem_mutex);
 	init_completion(&odp_data->notifier_completion);
@@ -384,6 +386,7 @@ struct ib_umem_odp *ib_alloc_odp_umem(struct ib_ucontext_per_mm *per_mm,
 out_page_list:
 	vfree(odp_data->page_list);
 out_odp_data:
+	mmdrop(umem->owning_mm);
 	kfree(odp_data);
 	return ERR_PTR(ret);
 }
