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authorGustavo A. R. Silva <gustavoars@kernel.org>2020-07-20 19:31:19 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-07-27 14:55:42 +0200
commit10cfde5dc695856c4fe93f0679d2fdd8e0d2a147 (patch)
tree49fef4c18607bd775cc027f0c202b8bf9e6b917d /drivers/acpi/acpica/utids.c
parentLinux 5.8-rc7 (diff)
downloadlinux-10cfde5dc695856c4fe93f0679d2fdd8e0d2a147.tar.xz
linux-10cfde5dc695856c4fe93f0679d2fdd8e0d2a147.zip
ACPICA: Replace one-element array with flexible-array
ACPICA commit 7ba2f3d91a32f104765961fda0ed78b884ae193d The current codebase makes use of one-element arrays in the following form: struct something { int length; u8 data[1]; }; struct something *instance; instance = kmalloc(sizeof(*instance) + size, GFP_KERNEL); instance->length = size; memcpy(instance->data, source, size); 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 linux codebase from now on. This issue was found with the help of Coccinelle and audited _manually_. [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") Link: https://github.com/acpica/acpica/commit/7ba2f3d9 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Erik Kaneda <erik.kaneda@intel.com> Signed-off-by: Bob Moore <robert.moore@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/acpica/utids.c')
-rw-r--r--drivers/acpi/acpica/utids.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/acpi/acpica/utids.c b/drivers/acpi/acpica/utids.c
index 3bb06935a2ad..3e68864ef242 100644
--- a/drivers/acpi/acpica/utids.c
+++ b/drivers/acpi/acpica/utids.c
@@ -263,8 +263,7 @@ acpi_ut_execute_CID(struct acpi_namespace_node *device_node,
* 3) Size of the actual CID strings
*/
cid_list_size = sizeof(struct acpi_pnp_device_id_list) +
- ((count - 1) * sizeof(struct acpi_pnp_device_id)) +
- string_area_size;
+ (count * sizeof(struct acpi_pnp_device_id)) + string_area_size;
cid_list = ACPI_ALLOCATE_ZEROED(cid_list_size);
if (!cid_list) {