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author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 07:20:17 -0600 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-23 19:24:51 +0100 |
commit | 6bc3f3979edce0b11deb685a4c817abb7d74b227 (patch) | |
tree | 3ce2cf2b7886400097251d33c05435653bcafe9b /drivers/usb/dwc2/hcd.h | |
parent | 2f41c8a25feb822203f92e17f3720397805d0cfd (diff) | |
download | linux-6bc3f3979edce0b11deb685a4c817abb7d74b227.tar.gz linux-6bc3f3979edce0b11deb685a4c817abb7d74b227.tar.bz2 linux-6bc3f3979edce0b11deb685a4c817abb7d74b227.zip |
USB: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200220132017.GA29262@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/dwc2/hcd.h')
-rw-r--r-- | drivers/usb/dwc2/hcd.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/dwc2/hcd.h b/drivers/usb/dwc2/hcd.h index 8ca6d12a6f57..1224fa9df604 100644 --- a/drivers/usb/dwc2/hcd.h +++ b/drivers/usb/dwc2/hcd.h @@ -199,7 +199,7 @@ struct dwc2_hcd_urb { u32 flags; u16 interval; struct dwc2_hcd_pipe_info pipe_info; - struct dwc2_hcd_iso_packet_desc iso_descs[0]; + struct dwc2_hcd_iso_packet_desc iso_descs[]; }; /* Phases for control transfers */ |