| Message ID | 20220401075747.2407536-1-lv.ruyi@zte.com.cn (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | usb: ftdi-elan: Fix undefined behaviour | expand |
On Fri, Apr 01, 2022 at 07:57:47AM +0000, cgel.zte@gmail.com wrote: > From: Lv Ruyi <lv.ruyi@zte.com.cn> > > The use of zero-sized array causes undefined behaviour when it is not > the last member in a structure. As it happens to be in this case. What do you mean by "undefined behavior" here? How is this working now? > Also, the current code makes use of a language extension to the C90 > standard, but the preferred mechanism to declare variable-length > types such as this one is a flexible array member, introduced in > C99: > > struct foo { > int stuff; > struct boo array[]; > }; gcc and clang both support [0] for a very long time so this isn't an issue. > By making use of the mechanism above, we will get a compiler warning > in case the flexible array does not occur last. Which is beneficial > to cultivate a high-quality code. > > Reported-by: Zeal Robot <zealci@zte.com.cn> > Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn> > --- > drivers/usb/misc/ftdi-elan.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c > index 6c38c62d29b2..e818d2ed6831 100644 > --- a/drivers/usb/misc/ftdi-elan.c > +++ b/drivers/usb/misc/ftdi-elan.c > @@ -171,7 +171,6 @@ struct usb_ftdi { > struct delayed_work command_work; > struct delayed_work respond_work; > struct u132_platform_data platform_data; > - struct resource resources[0]; > struct platform_device platform_dev; > unsigned char *bulk_in_buffer; > size_t bulk_in_size; > @@ -185,6 +184,7 @@ struct usb_ftdi { > int expected; > int received; > int ed_found; > + struct resource resources[]; How did you test and verify that this change is correct? thanks, greg k-h
diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c index 6c38c62d29b2..e818d2ed6831 100644 --- a/drivers/usb/misc/ftdi-elan.c +++ b/drivers/usb/misc/ftdi-elan.c @@ -171,7 +171,6 @@ struct usb_ftdi { struct delayed_work command_work; struct delayed_work respond_work; struct u132_platform_data platform_data; - struct resource resources[0]; struct platform_device platform_dev; unsigned char *bulk_in_buffer; size_t bulk_in_size; @@ -185,6 +184,7 @@ struct usb_ftdi { int expected; int received; int ed_found; + struct resource resources[]; }; #define kref_to_usb_ftdi(d) container_of(d, struct usb_ftdi, kref) #define platform_device_to_usb_ftdi(d) container_of(d, struct usb_ftdi, \