Re: [PATCH v2] vmxnet3: avoid assumption about invalid dma_pa in vmxnet3_set_mc()

[David Miller]

From: Alexey Khoroshilov 
Date: Sat, 15 Oct 2016 00:01:20 +0300

> vmxnet3_set_mc() checks new_table_pa returned by dma_map_single()
> with dma_mapping_error(), but even there it assumes zero is invalid pa
> (it assumes dma_mapping_error(...,0) returns true if new_table is NULL).
> 
> The patch adds an explicit variable to track status of new_table_pa.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> v2: use "bool" and "true"/"false" for boolean variables.
> Signed-off-by: Alexey Khoroshilov 

Applied.

[PATCH v2] vmxnet3: avoid assumption about invalid dma_pa in vmxnet3_set_mc()

[Alexey Khoroshilov]

vmxnet3_set_mc() checks new_table_pa returned by dma_map_single()
with dma_mapping_error(), but even there it assumes zero is invalid pa
(it assumes dma_mapping_error(...,0) returns true if new_table is NULL).

The patch adds an explicit variable to track status of new_table_pa.

Found by Linux Driver Verification project (linuxtesting.org).

v2: use "bool" and "true"/"false" for boolean variables.
Signed-off-by: Alexey Khoroshilov 
---
 drivers/net/vmxnet3/vmxnet3_drv.c | 17 ++---
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c 
b/drivers/net/vmxnet3/vmxnet3_drv.c
index b5554f2ebee4..ef83ae3b0a44 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -2279,6 +2279,7 @@ vmxnet3_set_mc(struct net_device *netdev)
>shared->devRead.rxFilterConf;
u8 *new_table = NULL;
dma_addr_t new_table_pa = 0;
+   bool new_table_pa_valid = false;
u32 new_mode = VMXNET3_RXM_UCAST;
 
if (netdev->flags & IFF_PROMISC) {
@@ -2307,13 +2308,15 @@ vmxnet3_set_mc(struct net_device *netdev)
new_table,
sz,
PCI_DMA_TODEVICE);
+   if (!dma_mapping_error(>pdev->dev,
+  new_table_pa)) {
+   new_mode |= VMXNET3_RXM_MCAST;
+   new_table_pa_valid = true;
+   rxConf->mfTablePA = cpu_to_le64(
+   new_table_pa);
+   }
}
-
-   if (!dma_mapping_error(>pdev->dev,
-  new_table_pa)) {
-   new_mode |= VMXNET3_RXM_MCAST;
-   rxConf->mfTablePA = cpu_to_le64(new_table_pa);
-   } else {
+   if (!new_table_pa_valid) {
netdev_info(netdev,
"failed to copy mcast list, setting 
ALL_MULTI\n");
new_mode |= VMXNET3_RXM_ALL_MULTI;
@@ -2338,7 +2341,7 @@ vmxnet3_set_mc(struct net_device *netdev)
   VMXNET3_CMD_UPDATE_MAC_FILTERS);
spin_unlock_irqrestore(>cmd_lock, flags);
 
-   if (new_table_pa)
+   if (new_table_pa_valid)
dma_unmap_single(>pdev->dev, new_table_pa,
 rxConf->mfTableLen, PCI_DMA_TODEVICE);
kfree(new_table);
-- 
2.7.4