summaryrefslogtreecommitdiff
path: root/net/mac80211/ieee80211_i.h
diff options
context:
space:
mode:
authorGustavo A. R. Silva <gustavoars@kernel.org>2020-05-07 21:59:07 +0300
committerJohannes Berg <johannes.berg@intel.com>2020-05-27 11:02:04 +0300
commit3c23215ba8c70c0e9b16beffb7f700a401391e38 (patch)
tree3b611a50cec3611a4d5b92af114dabbb8fe39d81 /net/mac80211/ieee80211_i.h
parent396fba0a59f3c94d6fd6443fbeabd8bd9e3956eb (diff)
downloadlinux-3c23215ba8c70c0e9b16beffb7f700a401391e38.tar.xz
mac80211: 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> Link: https://lore.kernel.org/r/20200507185907.GA15102@embeddedor Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/ieee80211_i.h')
-rw-r--r--net/mac80211/ieee80211_i.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 8cbae66b5cdb..2d1b6cb75497 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -267,7 +267,7 @@ struct probe_resp {
struct rcu_head rcu_head;
int len;
u16 csa_counter_offsets[IEEE80211_MAX_CSA_COUNTERS_NUM];
- u8 data[0];
+ u8 data[];
};
struct ps_data {