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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-27 00:26:12 +0300
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2020-03-05 18:41:58 +0300
commite8dc73c9f9ea554b36093dea23e4ca3b586105d7 (patch)
tree37e43c73b79a30f1ee8ff8abb303bf591c91afc8 /drivers/xen
parentf8788d86ab28f61f7b46eb6be375f8a726783636 (diff)
downloadlinux-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.h2
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 */