Sorry, I didn't find out about this email until now because it was
intercepted by my company's email server.
On 2023/11/22 20:10, Greg KH wrote:
On Wed, Nov 22, 2023 at 09:42:12AM +0800, Kunwu Chan wrote:
kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.
Signed-off-by: Kunwu Chan <chentao@xxxxxxxxxx>
---
drivers/usb/gadget/udc/aspeed-vhub/epn.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/gadget/udc/aspeed-vhub/epn.c b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
index 148d7ec3ebf4..e0854e878411 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/epn.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
@@ -826,6 +826,8 @@ struct ast_vhub_ep *ast_vhub_alloc_epn(struct ast_vhub_dev *d, u8 addr)
ep->vhub = vhub;
ep->ep.ops = &ast_vhub_epn_ops;
ep->ep.name = kasprintf(GFP_KERNEL, "ep%d", addr);
+ if (!ep->ep.name)
+ return NULL;
This will break things if this ever triggers. How was this tested? The
It's my fault, I think it's too simplistic. Compiled test only.
Cause I don't know how to test effectively. I didn't find a way to test
this in 'Documentation/usb/gadget-testing.rst'.
"slot" for this device will still be seen as used and so the resources
never freed and then you can run out of space for real devices, right?
Looks like the other error handling in this function below this call is
also broken, can you fix that up too?Yes, after reading the relevant code, I found that this is indeed a problem.
So I write the v2 patch below, but the same question bothering me, about
how to test effectively and what hardware equipment is needed? I'm new
to this area, do you have any suggestions?
The v2 patch look like:
@@ -826,6 +826,9 @@ struct ast_vhub_ep *ast_vhub_alloc_epn(struct
ast_vhub_dev *d, u8 addr)
ep->vhub = vhub;
ep->ep.ops = &ast_vhub_epn_ops;
ep->ep.name = kasprintf(GFP_KERNEL, "ep%d", addr);
+ if (!ep->ep.name)
+ goto fail_name;
+
d->epns[addr-1] = ep;
ep->epn.g_idx = i;
ep->epn.regs = vhub->regs + 0x200 + (i * 0x10);
@@ -834,11 +837,9 @@ struct ast_vhub_ep *ast_vhub_alloc_epn(struct
ast_vhub_dev *d, u8 addr)
AST_VHUB_EPn_MAX_PACKET +
8 * AST_VHUB_DESCS_COUNT,
&ep->buf_dma, GFP_KERNEL);
- if (!ep->buf) {
- kfree(ep->ep.name);
- ep->ep.name = NULL;
- return NULL;
- }
+ if (!ep->buf)
+ goto fail_dma;
+
ep->epn.descs = ep->buf + AST_VHUB_EPn_MAX_PACKET;
ep->epn.descs_dma = ep->buf_dma + AST_VHUB_EPn_MAX_PACKET;
@@ -851,4 +852,21 @@ struct ast_vhub_ep *ast_vhub_alloc_epn(struct
ast_vhub_dev *d, u8 addr)
ep->ep.caps.dir_out = true;
return ep;
+
+/* Free name & DMA buffers */
+fail_dma:
+ dma_free_coherent(&vhub->pdev->dev,
+ AST_VHUB_EPn_MAX_PACKET +
+ 8 * AST_VHUB_DESCS_COUNT,
+ ep->buf, ep->buf_dma);
+ ep->buf = NULL;
+ kfree(ep->ep.name);
+ ep->ep.name = NULL;
+
+/* Mark free */
+fail_name:
+ ep->dev->epns[ep->d_idx - 1] = NULL;
+ ep->dev = NULL;
+
+ return NULL;
}
thanks,
greg k-h
--
Thanks,
Kunwu
