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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-20 07:20:17 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-02-23 19:24:51 +0100
commit6bc3f3979edce0b11deb685a4c817abb7d74b227 (patch)
tree3ce2cf2b7886400097251d33c05435653bcafe9b /include/linux/usb
parent2f41c8a25feb822203f92e17f3720397805d0cfd (diff)
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 'include/linux/usb')
-rw-r--r--include/linux/usb/audio-v2.h2
-rw-r--r--include/linux/usb/audio-v3.h2
-rw-r--r--include/linux/usb/gadget.h2
-rw-r--r--include/linux/usb/hcd.h2
4 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/usb/audio-v2.h b/include/linux/usb/audio-v2.h
index ba4b3e3327ff..5e31740c7e40 100644
--- a/include/linux/usb/audio-v2.h
+++ b/include/linux/usb/audio-v2.h
@@ -153,7 +153,7 @@ struct uac2_feature_unit_descriptor {
__u8 bSourceID;
/* bmaControls is actually u32,
* but u8 is needed for the hybrid parser */
- __u8 bmaControls[0]; /* variable length */
+ __u8 bmaControls[]; /* variable length */
} __attribute__((packed));
/* 4.9.2 Class-Specific AS Interface Descriptor */
diff --git a/include/linux/usb/audio-v3.h b/include/linux/usb/audio-v3.h
index 6b708434b7f9..c69a6f2e6837 100644
--- a/include/linux/usb/audio-v3.h
+++ b/include/linux/usb/audio-v3.h
@@ -109,7 +109,7 @@ struct uac3_feature_unit_descriptor {
__u8 bSourceID;
/* bmaControls is actually u32,
* but u8 is needed for the hybrid parser */
- __u8 bmaControls[0]; /* variable length */
+ __u8 bmaControls[]; /* variable length */
/* wFeatureDescrStr omitted */
} __attribute__((packed));
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 124462d65eac..9411c08a5c7e 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -767,7 +767,7 @@ struct usb_gadget_strings {
struct usb_gadget_string_container {
struct list_head list;
- u8 *stash[0];
+ u8 *stash[];
};
/* put descriptor for string with that id into buf (buflen >= 256) */
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 712b2a603645..e12105ed3834 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -228,7 +228,7 @@ struct usb_hcd {
/* The HC driver's private data is stored at the end of
* this structure.
*/
- unsigned long hcd_priv[0]
+ unsigned long hcd_priv[]
__attribute__ ((aligned(sizeof(s64))));
};