From d1bd8ead126668a2d6c42d97cc3664e95b3fa1dc Mon Sep 17 00:00:00 2001
From: Petr Mladek <pmladek@suse.com>
Date: Wed, 14 Dec 2016 15:05:52 -0800
Subject: [PATCH] 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>
---
include/linux/kdb.h | 1 -
kernel/debug/kdb/kdb_io.c | 2 --
kernel/debug/kdb/kdb_main.c | 1 -
3 files changed, 4 deletions(-)
diff --git a/include/linux/kdb.h b/include/linux/kdb.h
index 410decacff8fc..eb706188dc232 100644
--- a/include/linux/kdb.h
+++ b/include/linux/kdb.h
@@ -77,7 +77,6 @@ extern int kdb_poll_idx;
* number whenever the kernel debugger is entered.
*/
extern int kdb_initial_cpu;
-extern atomic_t kdb_event;
/* Types and messages used for dynamically added kdb shell commands */
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 98c9011eac780..46f477bebe0c1 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -576,7 +576,6 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
KDB_STATE_SET(PRINTF_LOCK);
spin_lock_irqsave(&kdb_printf_lock, flags);
got_printf_lock = 1;
- atomic_inc(&kdb_event);
} else {
__acquire(kdb_printf_lock);
}
@@ -851,7 +850,6 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
got_printf_lock = 0;
spin_unlock_irqrestore(&kdb_printf_lock, flags);
KDB_STATE_CLEAR(PRINTF_LOCK);
- atomic_dec(&kdb_event);
} else {
__release(kdb_printf_lock);
}
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 2a20c0dfdafc7..ca183919d3027 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -60,7 +60,6 @@ int kdb_grep_trailing;
* Kernel debugger state flags
*/
int kdb_flags;
-atomic_t kdb_event;
/*
* kdb_lock protects updates to kdb_initial_cpu. Used to
--
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