[PATCH AUTOSEL 5.6 313/606] RDMA/mlx5: Fix NULL pointer dereference in destroy_prefetch_work

Sasha Levin
2020-06-09T00:18:43Z

From: Maor Gottlieb <maorg@mellanox.com>

[ Upstream commit 189277f3814c36133f4ff0352f4b5194a38486b6 ]

q_deferred_work isn't initialized when creating an explicit ODP memory
region. This can lead to a NULL pointer dereference when user performs
asynchronous prefetch MR. Fix it by initializing q_deferred_work for
explicit ODP.

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 4 PID: 6074 Comm: kworker/u16:6 Not tainted 5.7.0-rc1-for-upstream-perf-2020-04-17_07-03-39-64 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
Workqueue: events_unbound mlx5_ib_prefetch_mr_work [mlx5_ib]
RIP: 0010:__wake_up_common+0x49/0x120
Code: 04 89 54 24 0c 89 4c 24 08 74 0a 41 f6 01 04 0f 85 8e 00 00 00 48 8b 47 08 48 83 e8 18 4c 8d 67 08 48 8d 50 18 49 39 d4 74 66 <48> 8b 70 18 31 db 4c 8d 7e e8 eb 17 49 8b 47 18 48 8d 50 e8 49 8d
RSP: 0000:ffffc9000097bd88 EFLAGS: 00010082
RAX: ffffffffffffffe8 RBX: ffff888454cd9f90 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff888454cd9f90
RBP: ffffc9000097bdd0 R08: 0000000000000000 R09: ffffc9000097bdd0
R10: 0000000000000000 R11: 0000000000000001 R12: ffff888454cd9f98
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff88846fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000044c19e002 CR4: 0000000000760ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
__wake_up_common_lock+0x7a/0xc0
destroy_prefetch_work+0x5a/0x60 [mlx5_ib]
mlx5_ib_prefetch_mr_work+0x64/0x80 [mlx5_ib]
process_one_work+0x15b/0x360
worker_thread+0x49/0x3d0
kthread+0xf5/0x130
? rescuer_thread+0x310/0x310
? kthread_bind+0x10/0x10
ret_from_fork+0x1f/0x30

Fixes: de5ed007a03d ("IB/mlx5: Fix implicit ODP race")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200521072504.567406-1-leon@kernel.org
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/hw/mlx5/mr.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 6fa0a83c19de..9a1747a97fb6 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1319,6 +1319,7 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,

if (is_odp_mr(mr)) {
to_ib_umem_odp(mr->umem)->private = mr;
+ init_waitqueue_head(&mr->q_deferred_work);
atomic_set(&mr->num_deferred_work, 0);
err = xa_err(xa_store(&dev->odp_mkeys,
mlx5_base_mkey(mr->mmkey.key), &mr->mmkey,
--
2.25.1