Messages in this thread Patch in this message | | | Date | Fri, 13 Sep 2013 15:31:59 -0700 | From | Andi Kleen <> | Subject | [PATCH] jump_labels: Add WARN_ON for too early jump label use |
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I spent a few hours tracking down a regression in my TSX code, which turned out that it is not legal anymore to change jump labels before the jump label code is initialized.
Add a WARN_ON() for this case.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 297a924..c6c5290 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -17,6 +17,8 @@ #ifdef HAVE_JUMP_LABEL +static bool jump_label_initialized; + /* mutex to protect coming/going of the the jump_label table */ static DEFINE_MUTEX(jump_label_mutex); @@ -58,6 +60,8 @@ static void jump_label_update(struct static_key *key, int enable); void static_key_slow_inc(struct static_key *key) { + WARN_ON(!jump_label_initialized); + if (atomic_inc_not_zero(&key->enabled)) return; @@ -76,6 +80,7 @@ EXPORT_SYMBOL_GPL(static_key_slow_inc); static void __static_key_slow_dec(struct static_key *key, unsigned long rate_limit, struct delayed_work *work) { + WARN_ON(!jump_label_initialized); if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { WARN(atomic_read(&key->enabled) < 0, "jump label: negative count!\n"); @@ -213,6 +218,7 @@ void __init jump_label_init(void) #endif } jump_label_unlock(); + jump_label_initialized = true; } #ifdef CONFIG_MODULES -- ak@linux.intel.com -- Speaking for myself only
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