Re: [PATCH rdma-next] RDMA/mlx5: Add missing srcu_read_lock in ODP implicit flow

[Jason Gunthorpe <jgg@nvidia.com>]

On Sun, Jul 19, 2020 at 09:57:47AM +0300, Leon Romanovsky wrote:
> From: Maor Gottlieb <maorg@mellanox.com>
> 
> According to the locking scheme, mlx5_ib_update_xlt should be called
> with srcu_read_lock().
> This fixes the below LOCKDEP trace.
> 
> [  861.917222] WARNING: CPU: 1 PID: 1130 at
> drivers/infiniband/hw/mlx5/odp.c:132 mlx5_odp_populate_xlt+0x175/0x180
> [mlx5_ib]
> [  861.921080] Modules linked in: xt_conntrack xt_MASQUERADE
> nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat
> nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter overlay ib_srp
> scsi_transport_srp rpcrdma rdma_ucm ib_iser libiscsi
> scsi_transport_iscsi rdma_cm iw_cm ib_umad ib_ipoib ib_cm mlx5_ib
> ib_uverbs ib_core mlx5_core mlxfw ptp pps_core
> [  861.930133] CPU: 1 PID: 1130 Comm: kworker/u16:11 Tainted: G        W
> 5.8.0-rc5_for_upstream_debug_2020_07_13_11_04 #1
> [  861.932034] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
> rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
> [  861.933801] Workqueue: events_unbound mlx5_ib_prefetch_mr_work
> [mlx5_ib]
> [  861.934933] RIP: 0010:mlx5_odp_populate_xlt+0x175/0x180 [mlx5_ib]
> [  861.935954] Code: 08 e2 85 c0 0f 84 65 ff ff ff 49 8b 87 60 01 00 00
> be ff ff ff ff 48 8d b8 b0 39 00 00 e8 93 e0 50 e1 85 c0 0f 85 45 ff ff
> ff <0f> 0b e9 3e ff ff ff 0f 0b eb c7 0f 1f 44 00 00 48 8b 87 98 0f 00
> [  861.938855] RSP: 0018:ffff88840f44fc68 EFLAGS: 00010246
> [  861.939707] RAX: 0000000000000000 RBX: ffff88840cc9d000 RCX:
> ffff88840efcd940
> [  861.940788] RDX: 0000000000000000 RSI: ffff88844871b9b0 RDI:
> ffff88840efce100
> [  861.941880] RBP: ffff88840cc9d040 R08: 0000000000000040 R09:
> 0000000000000001
> [  861.943020] R10: ffff88846ced3068 R11: 0000000000000000 R12:
> 00000000000156ec
> [  861.944133] R13: 0000000000000004 R14: 0000000000000004 R15:
> ffff888439941000
> [  861.945228] FS:  0000000000000000(0000) GS:ffff88846fa80000(0000)
> knlGS:0000000000000000
> [  861.946557] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  861.947512] CR2: 00007f8536d12430 CR3: 0000000437a5e006 CR4:
> 0000000000360ea0
> [  861.948609] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000
> [  861.949684] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> 0000000000000400
> [  861.950804] Call Trace:
> [  861.951300]  mlx5_ib_update_xlt+0x37c/0x7c0 [mlx5_ib]
> [  861.952145]  pagefault_mr+0x315/0x440 [mlx5_ib]
> [  861.952895]  mlx5_ib_prefetch_mr_work+0x56/0xa0 [mlx5_ib]
> [  861.953763]  process_one_work+0x215/0x5c0
> [  861.954477]  worker_thread+0x3c/0x380
> [  861.955127]  ? process_one_work+0x5c0/0x5c0
> [  861.955851]  kthread+0x133/0x150
> [  861.956426]  ? kthread_park+0x90/0x90
> [  861.957061]  ret_from_fork+0x1f/0x30
> [  861.957686] irq event stamp: 199569
> [  861.958318] hardirqs last  enabled at (199577): [<ffffffff8119bf39>]
> console_unlock+0x439/0x590
> [  861.959720] hardirqs last disabled at (199584): [<ffffffff8119bb81>]
> console_unlock+0x81/0x590
> [  861.961080] softirqs last  enabled at (199600): [<ffffffff81e00293>]
> __do_softirq+0x293/0x47e
> [  861.971725] softirqs last disabled at (199613): [<ffffffff81c00f0f>]
> asm_call_on_stack+0xf/0x20
> [  861.973142] ---[ end trace e6f026aa6012c21e ]---
> 
> Fixes: 5256edcb98a1 ("RDMA/mlx5: Rework implicit ODP destroy")
> Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> ---
> It is not really need to go to -rc, not urgent.
> ---
>  drivers/infiniband/core/uverbs_std_types_mr.c | 2 +-
>  drivers/infiniband/core/verbs.c               | 3 +++
>  drivers/infiniband/hw/mlx5/odp.c              | 9 +++++++++
>  3 files changed, 13 insertions(+), 1 deletion(-)
> 
> --
> 2.26.2

Applied to for-next, thanks

Jason