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kdb: remove unused kdb_event handling
kdb_event state variable is only set but never checked in the kernel code. http://www.spinics.net/lists/kdb/msg01733.html suggests that this variable affected WARN_CONSOLE_UNLOCKED() in the original implementation. But this check never went upstream. The semantic is unclear and racy. The value is updated after the kdb_printf_lock is acquired and after it is released. It should be symmetric at minimum. The value should be manipulated either inside or outside the locked area. Fortunately, it seems that the original function is gone and we could simply remove the state variable. Link: http://lkml.kernel.org/r/1480412276-16690-2-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -77,7 +77,6 @@ extern int kdb_poll_idx;
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* number whenever the kernel debugger is entered.
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*/
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extern int kdb_initial_cpu;
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extern atomic_t kdb_event;
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/* Types and messages used for dynamically added kdb shell commands */
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@ -576,7 +576,6 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
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KDB_STATE_SET(PRINTF_LOCK);
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spin_lock_irqsave(&kdb_printf_lock, flags);
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got_printf_lock = 1;
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atomic_inc(&kdb_event);
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} else {
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__acquire(kdb_printf_lock);
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}
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@ -851,7 +850,6 @@ kdb_print_out:
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got_printf_lock = 0;
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spin_unlock_irqrestore(&kdb_printf_lock, flags);
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KDB_STATE_CLEAR(PRINTF_LOCK);
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atomic_dec(&kdb_event);
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} else {
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__release(kdb_printf_lock);
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}
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@ -60,7 +60,6 @@ int kdb_grep_trailing;
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* Kernel debugger state flags
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*/
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int kdb_flags;
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atomic_t kdb_event;
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/*
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* kdb_lock protects updates to kdb_initial_cpu. Used to
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