This came up in discussions when reviewing drm patches.
Cc: Eric Anholt <e...@anholt.net>
Cc: linux-doc@vger.kernel.org
Cc: Jonathan Corbet <cor...@lwn.net>
Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
--
Aside: I wonder whether we shouldn't move this to some other place and
rst-ify it? Any good suggestions?
-Daniel
---
Documentation/ioctl/botching-up-ioctls.txt | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Documentation/ioctl/botching-up-ioctls.txt
b/Documentation/ioctl/botching-up-ioctls.txt
index d02cfb48901c..883fb034bd04 100644
--- a/Documentation/ioctl/botching-up-ioctls.txt
+++ b/Documentation/ioctl/botching-up-ioctls.txt
@@ -73,7 +73,9 @@ will have a second iteration or at least an extension for any
given interface.
future extensions is going right down the gutters since someone will submit
an ioctl struct with random stack garbage in the yet unused parts. Which
then bakes in the ABI that those fields can never be used for anything else
- but garbage.
+ but garbage. This is also the reason why you must explicitly pad all
+ structures, even if you never use them in an array - the padding the
compiler
+ might insert could contain garbage.
* Have simple testcases for all of the above.
--
2.17.0
--
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