summaryrefslogtreecommitdiff
path: root/kernel/events/internal.h
diff options
context:
space:
mode:
authorGustavo A. R. Silva <gustavoars@kernel.org>2020-05-11 15:09:11 -0500
committerPeter Zijlstra <peterz@infradead.org>2020-05-19 20:34:16 +0200
commit8ac7571a8cd3c11da24c3c3555f6e40e33049609 (patch)
tree1d6b86b8a6f4aed651964bd0a88b3140d80a9f30 /kernel/events/internal.h
parent0813c40556fce1eeefb996e020cc5339e0b84137 (diff)
perf/x86: Replace zero-length array with flexible-array
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] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. 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 <gustavoars@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200511200911.GA13149@embeddedor
Diffstat (limited to 'kernel/events/internal.h')
0 files changed, 0 insertions, 0 deletions