Prevent calling roundup_pow_of_two() with value of 0 as it causes the
below UBSAN note.
Move this code and its few extra related lines to be called only when
it's really applicable.
UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13
shift exponent 64 is too large for 64-bit type 'long unsigned int'
CPU: 15 PID: 1639 Comm: live_migration Not tainted 6.1.0-rc4 #1116
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009),
BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x45/0x59
ubsan_epilogue+0x5/0x36
__ubsan_handle_shift_out_of_bounds.cold+0x61/0xef
? lock_is_held_type+0x98/0x110
? rcu_read_lock_sched_held+0x3f/0x70
mlx5vf_create_rc_qp.cold+0xe4/0xf2 [mlx5_vfio_pci]
mlx5vf_start_page_tracker+0x769/0xcd0 [mlx5_vfio_pci]
vfio_device_fops_unl_ioctl+0x63f/0x700 [vfio]
__x64_sys_ioctl+0x433/0x9a0
do_syscall_64+0x3d/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
</TASK>
Fixes: 79c3cf279926 ("vfio/mlx5: Init QP based resources for dirty tracking")
Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxx>
---
drivers/vfio/pci/mlx5/cmd.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
index 64e68d13cb98..c5dcddbc4126 100644
--- a/drivers/vfio/pci/mlx5/cmd.c
+++ b/drivers/vfio/pci/mlx5/cmd.c
@@ -1036,14 +1036,14 @@ mlx5vf_create_rc_qp(struct mlx5_core_dev *mdev,
if (!qp)
return ERR_PTR(-ENOMEM);
- qp->rq.wqe_cnt = roundup_pow_of_two(max_recv_wr);
- log_rq_stride = ilog2(MLX5_SEND_WQE_DS);
- log_rq_sz = ilog2(qp->rq.wqe_cnt);
err = mlx5_db_alloc_node(mdev, &qp->db, mdev->priv.numa_node);
if (err)
goto err_free;
if (max_recv_wr) {
+ qp->rq.wqe_cnt = roundup_pow_of_two(max_recv_wr);
+ log_rq_stride = ilog2(MLX5_SEND_WQE_DS);
+ log_rq_sz = ilog2(qp->rq.wqe_cnt);
err = mlx5_frag_buf_alloc_node(mdev,
wq_get_byte_sz(log_rq_sz, log_rq_stride),
&qp->buf, mdev->priv.numa_node);
--
2.18.1
