From: Yi Zhang yi.zhang@redhat.com
[ Upstream commit 60b1af64eb35074a4f2d41cc1e503a7671e68963 ]
'parent' sysfs reads will yield '\0' bytes when the interface name has 15 chars, and there will no "\n" output.
To reproduce, create one interface with 15 chars:
[root@test ~]# ip a s enp0s29u1u7u3c2 2: enp0s29u1u7u3c2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 1000 link/ether 02:21:28:57:47:17 brd ff:ff:ff:ff:ff:ff inet6 fe80::ac41:338f:5bcd:c222/64 scope link noprefixroute valid_lft forever preferred_lft forever [root@test ~]# modprobe rdma_rxe [root@test ~]# echo enp0s29u1u7u3c2 > /sys/module/rdma_rxe/parameters/add [root@test ~]# cat /sys/class/infiniband/rxe0/parent enp0s29u1u7u3c2[root@test ~]# [root@test ~]# f="/sys/class/infiniband/rxe0/parent" [root@test ~]# echo "$(<"$f")" -bash: warning: command substitution: ignored null byte in input enp0s29u1u7u3c2
Use scnprintf and PAGE_SIZE to fill the sysfs output buffer.
Cc: stable@vger.kernel.org Fixes: 8700e3e7c485 ("Soft RoCE driver") Link: https://lore.kernel.org/r/20200820153646.31316-1-yi.zhang@redhat.com Suggested-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Yi Zhang yi.zhang@redhat.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/sw/rxe/rxe_verbs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c index 26d66431f95b7..3b24ce8e3b3cb 100644 --- a/drivers/infiniband/sw/rxe/rxe_verbs.c +++ b/drivers/infiniband/sw/rxe/rxe_verbs.c @@ -1195,7 +1195,7 @@ static ssize_t rxe_show_parent(struct device *device, struct rxe_dev *rxe = container_of(device, struct rxe_dev, ib_dev.dev);
- return snprintf(buf, 16, "%s\n", rxe_parent_name(rxe, 1)); + return scnprintf(buf, PAGE_SIZE, "%s\n", rxe_parent_name(rxe, 1)); }
static DEVICE_ATTR(parent, S_IRUGO, rxe_show_parent, NULL);