(Extending Cc: list,)
On Sun, Jan 09, 2022 at 05:55:16PM +0800, Yanming Liu wrote:
Commit adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer") introduced a notion of maximum packet size in vmbus channel and used that size to initialize a buffer holding all incoming packet along with their vmbus packet header. Currently, some vmbus drivers set max_pkt_size to the size of their receive buffer passed to vmbus_recvpacket, however vmbus_open expects this size to also include vmbus packet header. This leads to corruption of the ring buffer state when receiving a maximum sized packet.
Specifically, in hv_balloon I have observed of a dm_unballoon_request message of 4096 bytes being truncated to 4080 bytes. When the driver tries to read next packet it starts from a wrong read_index, receives garbage and prints a lot of "Unhandled message: type: <garbage>" in dmesg.
The same mismatch also happens in hv_fcopy, hv_kvp, hv_snapshot, hv_util, hyperv_drm and hyperv_fb, though bad cases are not observed yet.
Allocate the buffer with HV_HYP_PAGE_SIZE more bytes to make room for the descriptor, assuming the vmbus packet header will never be larger than HV_HYP_PAGE_SIZE. This is essentially free compared to just adding 'sizeof(struct vmpacket_descriptor)' because these buffers are all more than HV_HYP_PAGE_SIZE bytes so kmalloc rounds them up anyway.
Fixes: adae1e931acd ("Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer") Suggested-by: Andrea Parri (Microsoft) parri.andrea@gmail.com Signed-off-by: Yanming Liu yanminglr@gmail.com
Thanks for sorting this out; the patch looks good to me:
Reviewed-by: Andrea Parri (Microsoft) parri.andrea@gmail.com
In future submissions (if any), please include LKML as well as subsystem lists&maintainers; scripts/get_maintainer.pl can be useful to this end.
Andrea
v2: Changed to modify max_pkt_size in individual drivers instead of in vmbus code as suggested by Andrea Parri.
drivers/gpu/drm/hyperv/hyperv_drm_proto.c | 2 ++ drivers/hv/hv_balloon.c | 7 +++++++ drivers/hv/hv_fcopy.c | 2 +- drivers/hv/hv_kvp.c | 2 +- drivers/hv/hv_snapshot.c | 2 +- drivers/hv/hv_util.c | 17 +++++++++++++++++ drivers/video/fbdev/hyperv_fb.c | 2 ++ 7 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c index c0155c6271bf..bf1548054276 100644 --- a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c +++ b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c @@ -478,6 +478,8 @@ int hyperv_connect_vsp(struct hv_device *hdev) struct drm_device *dev = &hv->dev; int ret;
- hdev->channel->max_pkt_size = HV_HYP_PAGE_SIZE + VMBUS_MAX_PACKET_SIZE;
- ret = vmbus_open(hdev->channel, VMBUS_RING_BUFSIZE, VMBUS_RING_BUFSIZE, NULL, 0, hyperv_receive, hdev); if (ret) {
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index ca873a3b98db..ee2527c3d3b8 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -1660,6 +1660,13 @@ static int balloon_connect_vsp(struct hv_device *dev) unsigned long t; int ret;
- /*
* max_pkt_size should be large enough for one vmbus packet header plus
* our receive buffer size. We assume vmbus packet header is smaller
* than HV_HYP_PAGE_SIZE.
*/
- dev->channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
- ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, balloon_onchannelcallback, dev); if (ret)
diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c index 660036da7449..07a508ce65db 100644 --- a/drivers/hv/hv_fcopy.c +++ b/drivers/hv/hv_fcopy.c @@ -349,7 +349,7 @@ int hv_fcopy_init(struct hv_util_service *srv) { recv_buffer = srv->recv_buffer; fcopy_transaction.recv_channel = srv->channel;
- fcopy_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
fcopy_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 3;
/*
- When this driver loads, the user level daemon that
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c index c698592b83e4..b85d725ae5b1 100644 --- a/drivers/hv/hv_kvp.c +++ b/drivers/hv/hv_kvp.c @@ -757,7 +757,7 @@ hv_kvp_init(struct hv_util_service *srv) { recv_buffer = srv->recv_buffer; kvp_transaction.recv_channel = srv->channel;
- kvp_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 4;
kvp_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 5;
/*
- When this driver loads, the user level daemon that
diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c index 6018b9d1b1fb..dba6baacbf17 100644 --- a/drivers/hv/hv_snapshot.c +++ b/drivers/hv/hv_snapshot.c @@ -375,7 +375,7 @@ hv_vss_init(struct hv_util_service *srv) } recv_buffer = srv->recv_buffer; vss_transaction.recv_channel = srv->channel;
- vss_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
vss_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 3;
/*
- When this driver loads, the user level daemon that
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c index 835e6039c186..a7b88c067c07 100644 --- a/drivers/hv/hv_util.c +++ b/drivers/hv/hv_util.c @@ -112,6 +112,8 @@ static int hv_shutdown_init(struct hv_util_service *srv)
hibernation_supported = hv_is_hibernation_supported();
- channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
- return 0;
}
@@ -133,9 +135,11 @@ static struct hv_util_service util_timesynch = { .util_deinit = hv_timesync_deinit, };
+static int heartbeat_init(struct hv_util_service *src); static void heartbeat_onchannelcallback(void *context); static struct hv_util_service util_heartbeat = { .util_cb = heartbeat_onchannelcallback,
- .util_init = heartbeat_init,
};
static struct hv_util_service util_kvp = { @@ -553,6 +557,15 @@ static void heartbeat_onchannelcallback(void *context) } }
+static int heartbeat_init(struct hv_util_service *srv) +{
- struct vmbus_channel *channel = srv->channel;
- channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
- return 0;
+}
#define HV_UTIL_RING_SEND_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE) #define HV_UTIL_RING_RECV_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE)
@@ -734,6 +747,8 @@ static struct ptp_clock *hv_ptp_clock;
static int hv_timesync_init(struct hv_util_service *srv) {
struct vmbus_channel *channel = srv->channel;
spin_lock_init(&host_ts.lock);
INIT_WORK(&adj_time_work, hv_set_host_time);
@@ -750,6 +765,8 @@ static int hv_timesync_init(struct hv_util_service *srv) hv_ptp_clock = NULL; }
- channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
- return 0;
}
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c index 23999df52739..ae4240777f7d 100644 --- a/drivers/video/fbdev/hyperv_fb.c +++ b/drivers/video/fbdev/hyperv_fb.c @@ -636,6 +636,8 @@ static int synthvid_connect_vsp(struct hv_device *hdev) struct hvfb_par *par = info->par; int ret;
- hdev->channel->max_pkt_size = HV_HYP_PAGE_SIZE + MAX_VMBUS_PKT_SIZE;
- ret = vmbus_open(hdev->channel, RING_BUFSIZE, RING_BUFSIZE, NULL, 0, synthvid_receive, hdev); if (ret) {
-- 2.34.1