From: Sasha Levin sashal@kernel.org Sent: Wednesday, October 31, 2018 16:05 To: stable@vger.kernel.org; linux-kernel@vger.kernel.org Cc: Dexuan Cui decui@microsoft.com; KY Srinivasan kys@microsoft.com; Haiyang Zhang haiyangz@microsoft.com; Stephen Hemminger sthemmin@microsoft.com; Stable@vger.kernel.org; Greg Kroah-Hartman gregkh@linuxfoundation.org; Sasha Levin sashal@kernel.org Subject: [PATCH AUTOSEL 4.19 109/146] Drivers: hv: kvp: Fix two "this statement may fall through" warnings
From: Dexuan Cui decui@microsoft.com
[ Upstream commit fc62c3b1977d62e6374fd6e28d371bb42dfa5c9d ]
We don't need to call process_ib_ipinfo() if message->kvp_hdr.operation is KVP_OP_GET_IP_INFO in kvp_send_key(), because here we just need to pass on the op code from the host to the userspace; when the userspace returns the info requested by the host, we pass the info on to the host in kvp_respond_to_host() -> process_ob_ipinfo(). BTW, the current buggy code actually doesn't cause any harm, because only message->kvp_hdr.operation is used by the userspace, in the case of KVP_OP_GET_IP_INFO.
The patch also adds a missing "break;" in kvp_send_key(). BTW, the current buggy code actually doesn't cause any harm, because in the case of KVP_OP_SET, the unexpected fall-through corrupts message->body.kvp_set.data.key_size, but that is not really used: see the definition of struct hv_kvp_exchg_msg_value.
Signed-off-by: Dexuan Cui decui@microsoft.com Cc: K. Y. Srinivasan kys@microsoft.com Cc: Haiyang Zhang haiyangz@microsoft.com Cc: Stephen Hemminger sthemmin@microsoft.com Cc: Stable@vger.kernel.org Signed-off-by: K. Y. Srinivasan kys@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org
drivers/hv/hv_kvp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c index 5eed1e7da15c..57715a0c8120 100644 --- a/drivers/hv/hv_kvp.c +++ b/drivers/hv/hv_kvp.c @@ -353,7 +353,6 @@ static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
- default: utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id, MAX_ADAPTER_ID_SIZE, UTF16_LITTLE_ENDIAN,
@@ -406,7 +405,7 @@ kvp_send_key(struct work_struct *dummy) process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO); break; case KVP_OP_GET_IP_INFO:
process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
/* We only need to pass on message->kvp_hdr.operation. */@@ -446,6 +445,9 @@ kvp_send_key(struct work_struct *dummy) break;
}
break;- case KVP_OP_GET: message->body.kvp_set.data.key_size = utf16s_to_utf8s(
-- 2.17.1
This patch caused a regression and the fix (https://lkml.org/lkml/2018/10/18/288) has not been in Greg's tree yet...
For now, please don't backport this patch to the stable kernels (4.19, 4.18, 4.14, 4.9, 4.4, 3.18,etc). Sorry for the trouble!
-- Dexuan