kernel-hacking-2024-linux-s.../include/xen
Gustavo A. R. Silva e8dc73c9f9 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 7649773293 ("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>
2020-03-05 09:41:58 -06:00
..
arm swiotlb-xen: simplify cache maintainance 2019-09-11 12:43:27 +02:00
interface xen: Replace zero-length array with flexible-array member 2020-03-05 09:41:58 -06:00
acpi.h
balloon.h xen: remove tmem driver 2019-07-17 08:09:58 +02:00
events.h xen/events: fix binding user event channels to cpus 2019-07-17 08:09:57 +02:00
features.h
grant_table.h xen/grant-table: Allow allocating buffers suitable for DMA 2018-07-26 23:05:14 -04:00
hvc-console.h
hvm.h
mem-reservation.h xen/balloon: add runtime control for scrubbing ballooned out pages 2018-09-14 08:51:10 -04:00
page.h
platform_pci.h
swiotlb-xen.h dma-mapping: drop the dev argument to arch_sync_dma_for_* 2019-11-20 20:31:38 +01:00
xen-front-pgdir-shbuf.h xen: Introduce shared buffer helpers for page directory... 2018-12-18 12:15:55 -05:00
xen-ops.h sched/rt, xen: Use CONFIG_PREEMPTION 2019-12-08 14:37:36 +01:00
xen.h block: pass page to xen_biovec_phys_mergeable 2019-04-01 12:11:13 -06:00
xenbus.h xenbus/backend: Protect xenbus callback with lock 2020-01-29 07:35:49 -06:00
xenbus_dev.h