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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-03-19 16:32:26 -0500
committerWei Liu <wei.liu@kernel.org>2020-03-21 16:26:12 +0000
commit032d4a4802209fe25ce44deb2c002dccf663925f (patch)
tree1538ad4ea320bc32f78115b1b729fedf27967b31 /drivers/hv
parentfb33c6510d5595144d585aa194d377cf74d31911 (diff)
hv: hyperv_vmbus.h: 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> Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/hyperv_vmbus.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index f5fa3b3c9baf..70b30e223a57 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -292,7 +292,7 @@ struct vmbus_msginfo {
struct list_head msglist_entry;
/* The message itself */
- unsigned char msg[0];
+ unsigned char msg[];
};