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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2016-01-20 15:00:51 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-01-17 09:35:25 +0100
commit0753661d5b17251a0a02a7b6b1ae596f3e9cd784 (patch)
tree8cb62cbefde4fb1fdfc6f768cb25af1a1fcb518d /net
parentf2c131d05d86ea7fefd0f866ccd6b3565ef28f78 (diff)
net/mac80211/debugfs.c: prevent build failure with CONFIG_UBSAN=y
commit 68920c973254c5b71a684645c5f6f82d6732c5d6 upstream. 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> [Daniel: backport to 4.4.] Signed-off-by: Daniel Wagner <daniel.wagner@siemens.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/mac80211/debugfs.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index 4d2aaebd4f97..e546a987a9d3 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -91,7 +91,7 @@ static const struct file_operations reset_ops = {
};
#endif
-static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = {
+static const char *hw_flag_names[] = {
#define FLAG(F) [IEEE80211_HW_##F] = #F
FLAG(HAS_RATE_CONTROL),
FLAG(RX_INCLUDES_FCS),
@@ -125,9 +125,6 @@ static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = {
FLAG(TDLS_WIDER_BW),
FLAG(SUPPORTS_AMSDU_IN_AMPDU),
FLAG(BEACON_TX_STATUS),
-
- /* keep last for the build bug below */
- (void *)0x1
#undef FLAG
};
@@ -147,7 +144,7 @@ static ssize_t hwflags_read(struct file *file, char __user *user_buf,
/* fail compilation if somebody adds or removes
* a flag without updating the name array above
*/
- BUILD_BUG_ON(hw_flag_names[NUM_IEEE80211_HW_FLAGS] != (void *)0x1);
+ BUILD_BUG_ON(ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS);
for (i = 0; i < NUM_IEEE80211_HW_FLAGS; i++) {
if (test_bit(i, local->hw.flags))