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| author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2016-01-20 15:00:51 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-20 17:09:18 -0800 |
| commit | 68920c973254c5b71a684645c5f6f82d6732c5d6 (patch) | |
| tree | aaa550695d20816828ea3f17285863591203a3cc | |
| parent | 5c9cf8af2e77388f1da81c39237fb4f20c2f85d5 (diff) | |
| download | linux-68920c973254c5b71a684645c5f6f82d6732c5d6.tar.bz2 | |
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>
| -rw-r--r-- | net/mac80211/debugfs.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c index abbdff03ce92..3e24d0ddb51b 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), @@ -126,9 +126,6 @@ static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = { FLAG(SUPPORTS_AMSDU_IN_AMPDU), FLAG(BEACON_TX_STATUS), FLAG(NEEDS_UNIQUE_STA_ADDR), - - /* keep last for the build bug below */ - (void *)0x1 #undef FLAG }; @@ -148,7 +145,7 @@ 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)) |