[PATCH AUTOSEL 4.19 14/15] RDMA/hfi1: Prevent panic when SDMA is disabled

Sasha Levin
2022-06-01T14:13:32Z

From: Douglas Miller <doug.miller@cornelisnetworks.com>

[ Upstream commit 629e052d0c98e46dde9f0824f0aa437f678d9b8f ]

If the hfi1 module is loaded with HFI1_CAP_SDMA off, a call to
hfi1_write_iter() will dereference a NULL pointer and panic. A typical
stack frame is:

sdma_select_user_engine [hfi1]
hfi1_user_sdma_process_request [hfi1]
hfi1_write_iter [hfi1]
do_iter_readv_writev
do_iter_write
vfs_writev
do_writev
do_syscall_64

The fix is to test for SDMA in hfi1_write_iter() and fail the I/O with
EINVAL.

Link: https://lore.kernel.org/r/20220520183706.48973.79803.stgit@awfm-01.cornelisnetworks.com
Signed-off-by: Douglas Miller <doug.miller@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/hw/hfi1/file_ops.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index adeb259458de..64ee11542a56 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -308,6 +308,8 @@ static ssize_t hfi1_write_iter(struct kiocb *kiocb, struct iov_iter *from)
unsigned long dim = from->nr_segs;
int idx;

+ if (!HFI1_CAP_IS_KSET(SDMA))
+ return -EINVAL;
idx = srcu_read_lock(&fd->pq_srcu);
pq = srcu_dereference(fd->pq, &fd->pq_srcu);
if (!cq || !pq) {
--
2.35.1