[PATCH rdma-next v3 5/5] RDMA/mlx5: Fix null-ptr-deref in Raw Packet QP creation

Edward Srouji
2026-04-27T11:03:41Z

From: Michael Guralnik <michaelgur@nvidia.com>

Raw Packet QPs are unique in that they support separate send and receive
queues, using 2 different user-provided buffers.
They can also be created with one of the queues having size 0, allowing
a send-only or receive-only QP.

The Raw Packet RQ umem is created in the common user QP creation path,
which allows zero-length queues. Add a later validation of the RQ umem
in Raw Packet QP creation path when an RQ was requested.

This prevents possible null-ptr dereference crashes, as seen in the
below trace:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 6 UID: 0 PID: 3539 Comm: raw_packet_umem Not tainted 6.19.0-rc1+ #166 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
RIP: 0010:__mlx5_umem_find_best_quantized_pgoff+0x37/0x280 [mlx5_ib]
Code: ff df 41 57 49 89 ff 41 56 41 55 41 89 d5 41 54 4d 89 cc 4c 8d 4f 30 55 4c 89 ca 48 89 f5 53 48 c1 ea 03 48 89 cb 48 83 ec 18 <80> 3c 02 00 44 89 04 24 0f 85 01 02 00 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ff1100013966f4e0 EFLAGS: 00010282
RAX: dffffc0000000000 RBX: 00000000ffffffc0 RCX: 00000000ffffffc0
RDX: 0000000000000006 RSI: 00000ffffffff000 RDI: 0000000000000000
RBP: 00000ffffffff000 R08: 0000000000000040 R09: 0000000000000030
R10: 0000000000000000 R11: 0000000000000000 R12: ff1100013966f648
R13: 0000000000000005 R14: ff1100013966f980 R15: 0000000000000000
FS: 00007fae6c82f740(0000) GS:ff11000898ba1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 000000010f96c005 CR4: 0000000000373eb0
Call Trace:
<TASK>
create_qp+0x747d/0xc740 [mlx5_ib]
? is_module_address+0x18/0x110
? _create_user_qp.constprop.0+0x18e0/0x18e0 [mlx5_ib]
? __module_address+0x49/0x210
? is_module_address+0x68/0x110
? static_obj+0x67/0x90
? lockdep_init_map_type+0x58/0x200
mlx5_ib_create_qp+0xc85/0x2620 [mlx5_ib]
? find_held_lock+0x2b/0x80
? create_qp+0xc740/0xc740 [mlx5_ib]
? lock_release+0xcb/0x260
? lockdep_init_map_type+0x58/0x200
? __init_swait_queue_head+0xcb/0x150
create_qp.part.0+0x558/0x7c0 [ib_core]
ib_create_qp_user+0xa0/0x4f0 [ib_core]
? rdma_lookup_get_uobject+0x1e4/0x400 [ib_uverbs]
create_qp+0xe4f/0x1d10 [ib_uverbs]
? ib_uverbs_rereg_mr+0xd40/0xd40 [ib_uverbs]
? ib_uverbs_cq_event_handler+0x120/0x120 [ib_uverbs]
? __might_fault+0x81/0x100
? lock_release+0xcb/0x260
? _copy_from_user+0x3e/0x90
ib_uverbs_create_qp+0x10a/0x150 [ib_uverbs]
? ib_uverbs_ex_create_qp+0xe0/0xe0 [ib_uverbs]
? __might_fault+0x81/0x100
? lock_release+0xcb/0x260
ib_uverbs_write+0x7e5/0xc90 [ib_uverbs]
? uverbs_devnode+0xc0/0xc0 [ib_uverbs]
? lock_acquire+0xfa/0x2b0
? find_held_lock+0x2b/0x80
? finish_task_switch.isra.0+0x189/0x6c0
vfs_write+0x1c0/0xf70
? lockdep_hardirqs_on_prepare+0xde/0x170
? kernel_write+0x5a0/0x5a0
? __switch_to+0x527/0xe60
? __schedule+0x10a3/0x3950
? io_schedule_timeout+0x110/0x110
ksys_write+0x170/0x1c0
? __x64_sys_read+0xb0/0xb0
? trace_hardirqs_off.part.0+0x4e/0xe0
do_syscall_64+0x70/0x1360
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7fae6ca3118d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 5b cc 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffe678ca308 EFLAGS: 00000213 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffe678ca448 RCX: 00007fae6ca3118d
RDX: 0000000000000070 RSI: 0000200000000280 RDI: 0000000000000003
RBP: 00007ffe678ca320 R08: 00000000ffffffff R09: 00007fae6c8ec5b8
R10: 0000000000000064 R11: 0000000000000213 R12: 0000000000000001
R13: 0000000000000000 R14: 00007fae6cb71000 R15: 0000000000404df0
</TASK>
Modules linked in: mlx5_ib mlx5_fwctl mlx5_core bonding ip6_gre ip6_tunnel tunnel6 ip_gre gre rdma_ucm ib_uverbs rdma_cm iw_cm ib_ipoib ib_cm ib_umad ib_core rpcsec_gss_krb5 auth_rpcgss oid_registry overlay nfnetlink zram zsmalloc fuse scsi_transport_iscsi [last unloaded: mlx5_core]
---[ end trace 0000000000000000 ]---
RIP: 0010:__mlx5_umem_find_best_quantized_pgoff+0x37/0x280 [mlx5_ib]

Fixes: 0fb2ed66a14c ("IB/mlx5: Add create and destroy functionality for Raw Packet QP")
Signed-off-by: Michael Guralnik <michaelgur@nvidia.com>
Reviewed-by: Maher Sanalla <msanalla@nvidia.com>
Signed-off-by: Edward Srouji <edwards@nvidia.com>
---
drivers/infiniband/hw/mlx5/qp.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 8f50e7342a76949f7caf24f9ea32243ea60e2b83..1611a704c1b33231063f5ff0f155ce7d5148e508 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -1603,6 +1603,11 @@ static int create_raw_packet_qp(struct mlx5_ib_dev *dev, struct mlx5_ib_qp *qp,
}

if (qp->rq.wqe_cnt) {
+ if (!rq->base.ubuffer.umem) {
+ err = -EINVAL;
+ goto err_destroy_sq;
+ }
+
rq->base.container_mibqp = qp;

if (qp->flags & IB_QP_CREATE_CVLAN_STRIPPING)

--
2.49.0