This patch fixes below kernel crash on memory registration for rxe
and other transport drivers which has dma_ops extension.
IB/core invokes ib_map_sg_attrs() in generic manner with dma attributes
which is used by mlx5 and mthca adapters. However in doing so it
ignored honoring dma_ops extension of software based transports for
sg map/unmap operation. This results in calling dma_map_sg_attrs of
hardware virtual device resulting in crash for null reference.
We extend the core to support sg_map/unmap_attrs and transport drivers
to implement those dma_ops callback functions.
Verified usign perftest applications.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff81032a75>] check_addr+0x35/0x60
...
Call Trace:
[<ffffffff81032b39>] ? nommu_map_sg+0x99/0xd0
[<ffffffffa02b31c6>] ib_umem_get+0x3d6/0x470 [ib_core]
[<ffffffffa01cc329>] rxe_mem_init_user+0x49/0x270 [rdma_rxe]
[<ffffffffa01c793a>] ? rxe_add_index+0xca/0x100 [rdma_rxe]
[<ffffffffa01c995f>] rxe_reg_user_mr+0x9f/0x130 [rdma_rxe]
[<ffffffffa00419fe>] ib_uverbs_reg_mr+0x14e/0x2c0 [ib_uverbs]
[<ffffffffa003d3ab>] ib_uverbs_write+0x15b/0x3b0 [ib_uverbs]
[<ffffffff811e92a6>] ? mem_cgroup_commit_charge+0x76/0xe0
[<ffffffff811af0a9>] ? page_add_new_anon_rmap+0x89/0xc0
[<ffffffff8117e6c9>] ? lru_cache_add_active_or_unevictable+0x39/0xc0
[<ffffffff811f0da8>] __vfs_write+0x28/0x120
[<ffffffff811f1239>] ? rw_verify_area+0x49/0xb0
[<ffffffff811f1492>] vfs_write+0xb2/0x1b0
[<ffffffff811f27d6>] SyS_write+0x46/0xa0
[<ffffffff814f7d32>] entry_SYSCALL_64_fastpath+0x1a/0xa4
Signed-off-by: Parav Pandit <pandit.parav@gmail.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Soft RoCE (RXE) - The software RoCE driver
ib_rxe implements the RDMA transport and registers to the RDMA core
device as a kernel verbs provider. It also implements the packet IO
layer. On the other hand ib_rxe registers to the Linux netdev stack
as a udp encapsulating protocol, in that case RDMA, for sending and
receiving packets over any Ethernet device. This yields a RDMA
transport over the UDP/Ethernet network layer forming a RoCEv2
compatible device.
The configuration procedure of the Soft RoCE drivers requires
binding to any existing Ethernet network device. This is done with
/sys interface.
A userspace Soft RoCE library (librxe) provides user applications
the ability to run with Soft RoCE devices. The use of rxe verbs ins
user space requires the inclusion of librxe as a device specifics
plug-in to libibverbs. librxe is packaged separately.
Architecture:
+-----------------------------------------------------------+
| Application |
+-----------------------------------------------------------+
+-----------------------------------+
| libibverbs |
User +-----------------------------------+
+----------------+ +----------------+
| librxe | | HW RoCE lib |
+----------------+ +----------------+
+---------------------------------------------------------------+
+--------------+ +------------+
| Sockets | | RDMA ULP |
+--------------+ +------------+
+--------------+ +---------------------+
| TCP/IP | | ib_core |
+--------------+ +---------------------+
+------------+ +----------------+
Kernel | ib_rxe | | HW RoCE driver |
+------------+ +----------------+
+------------------------------------+
| NIC driver |
+------------------------------------+
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+-----------------------------------------------------------+
| Application |
+-----------------------------------------------------------+
+-----------------------------------+
| libibverbs |
User +-----------------------------------+
+----------------+ +----------------+
| librxe | | HW RoCE lib |
+----------------+ +----------------+
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+--------------+ +------------+
| Sockets | | RDMA ULP |
+--------------+ +------------+
+--------------+ +---------------------+
| TCP/IP | | ib_core |
+--------------+ +---------------------+
+------------+ +----------------+
Kernel | ib_rxe | | HW RoCE driver |
+------------+ +----------------+
+------------------------------------+
| NIC driver |
+------------------------------------+
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Soft RoCE resources:
[1[ https://github.com/SoftRoCE/librxe-dev librxe - source code in
Github
[2] https://github.com/SoftRoCE/rxe-dev/wiki/rxe-dev:-Home - Soft RoCE
Wiki page
[3] https://github.com/SoftRoCE/librxe-dev - Soft RoCE userspace library
Signed-off-by: Kamal Heib <kamalh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Parav Pandit
Moni Shoua