diff options
| author | Andrey Ryabinin <aryabinin@virtuozzo.com> | 2016-01-20 15:00:51 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-17 09:35:25 +0100 |
| commit | 0753661d5b17251a0a02a7b6b1ae596f3e9cd784 (patch) | |
| tree | 8cb62cbefde4fb1fdfc6f768cb25af1a1fcb518d /net | |
| parent | f2c131d05d86ea7fefd0f866ccd6b3565ef28f78 (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.c | 7 |
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)) |