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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-27 00:26:12 +0300 |
|---|---|---|
| committer | Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2020-03-05 18:41:58 +0300 |
| commit | e8dc73c9f9ea554b36093dea23e4ca3b586105d7 (patch) | |
| tree | 37e43c73b79a30f1ee8ff8abb303bf591c91afc8 /drivers/xen | |
| parent | f8788d86ab28f61f7b46eb6be375f8a726783636 (diff) | |
| download | linux-e8dc73c9f9ea554b36093dea23e4ca3b586105d7.tar.xz | |
xen: 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/20200226212612.GA4663@embeddedor
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/xen-pciback/pciback.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h index ce1077e32466..7c95516a860f 100644 --- a/drivers/xen/xen-pciback/pciback.h +++ b/drivers/xen/xen-pciback/pciback.h @@ -52,7 +52,7 @@ struct xen_pcibk_dev_data { unsigned int ack_intr:1; /* .. and ACK-ing */ unsigned long handled; unsigned int irq; /* Saved in case device transitions to MSI/MSI-X */ - char irq_name[0]; /* xen-pcibk[000:04:00.0] */ + char irq_name[]; /* xen-pcibk[000:04:00.0] */ }; /* Used by XenBus and xen_pcibk_ops.c */ |