]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
net/mac80211/debugfs.c: prevent build failure with CONFIG_UBSAN=y
authorAndrey Ryabinin <aryabinin@virtuozzo.com>
Wed, 20 Jan 2016 23:00:51 +0000 (15:00 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 21 Jan 2016 01:09:18 +0000 (17:09 -0800)
commit68920c973254c5b71a684645c5f6f82d6732c5d6
treeaaa550695d20816828ea3f17285863591203a3cc
parent5c9cf8af2e77388f1da81c39237fb4f20c2f85d5
net/mac80211/debugfs.c: prevent build failure with CONFIG_UBSAN=y

With upcoming CONFIG_UBSAN the following BUILD_BUG_ON in
net/mac80211/debugfs.c starts to trigger:

  BUILD_BUG_ON(hw_flag_names[NUM_IEEE80211_HW_FLAGS] != (void *)0x1);

It seems, that compiler instrumentation causes some code
deoptimizations.  Because of that GCC is not being able to resolve
condition in BUILD_BUG_ON() at compile time.

We could make size of hw_flag_names array unspecified and replace the
condition in BUILD_BUG_ON() with following:

  ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS

That will have the same effect as before (adding new flag without
updating array will trigger build failure) except it doesn't fail with
CONFIG_UBSAN.  As a bonus this patch slightly decreases size of
hw_flag_names array.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
net/mac80211/debugfs.c