diff options
author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-20 07:20:17 -0600 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-23 19:24:51 +0100 |
commit | 6bc3f3979edce0b11deb685a4c817abb7d74b227 (patch) | |
tree | 3ce2cf2b7886400097251d33c05435653bcafe9b /drivers/usb/host/ohci.h | |
parent | 2f41c8a25feb822203f92e17f3720397805d0cfd (diff) | |
download | linux-stable-6bc3f3979edce0b11deb685a4c817abb7d74b227.tar.gz linux-stable-6bc3f3979edce0b11deb685a4c817abb7d74b227.tar.bz2 linux-stable-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/host/ohci.h')
-rw-r--r-- | drivers/usb/host/ohci.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/usb/host/ohci.h b/drivers/usb/host/ohci.h index b015b00774b2..27c26ca10bfd 100644 --- a/drivers/usb/host/ohci.h +++ b/drivers/usb/host/ohci.h @@ -337,7 +337,7 @@ typedef struct urb_priv { u16 length; // # tds in this request u16 td_cnt; // tds already serviced struct list_head pending; - struct td *td [0]; // all TDs in this request + struct td *td[]; // all TDs in this request } urb_priv_t; @@ -435,7 +435,7 @@ struct ohci_hcd { struct dentry *debug_dir; /* platform-specific data -- must come last */ - unsigned long priv[0] __aligned(sizeof(s64)); + unsigned long priv[] __aligned(sizeof(s64)); }; |