diff mbox series

[vfio,1/6] vfio/mlx5: Fix UBSAN note

Message ID 20221229100734.224388-2-yishaih@nvidia.com (mailing list archive)
State New, archived
Headers show
Series Move to use cgroups for userspace persistent allocations | expand

Commit Message

Yishai Hadas Dec. 29, 2022, 10:07 a.m. UTC 
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@nvidia.com>
---
 drivers/vfio/pci/mlx5/cmd.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox series

Patch

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);